(In humans)
Sex-determination in humans Refer to Answer No. 24. Sex-determination in birds Refer to Answer No. 6.
Question 104. During a medical investigation, an infant was found to possess an extra chromosome 21. Describe the symptoms the child is likely to develop later in the life. (Delhi 2017) Or Explain how trisomy of 21st chromosome occurs in humans. List any four characteristic features in an individual suffering from it. (Foreign 2012) Or Name the genetic disorder caused by trisomy of 21st chromosome in a human. Write the diagnostic features of the disorder. (Delhi 2011C) Answer: An additional copy of chromosome number 21 (trisomy of chromosome number 21) in humans results in Down’s syndrome. Following characteristic symptoms are likely to develop in the child suffering from Down’s syndrome
Question 105. Both haemophilia and thalassemia are blood related disorders in humans. Write their causes and the difference between the two. Name the category of genetic disorder they both come under. (All India 2017) Answer: Haemophilia and thalassemia both are Mendelian or gene related human disorders. Cause of Haemophilia It is caused due to the absence of antihaemophilic globulin and plasma thromboplastin factor. Cause of Thalassemia It is caused due to mutation or deletion of the genes controlling the formation of globin chains (a and P) of haemoglobin. Differences between haemophilia and thalassemia are as follows
Haemophilia | Thalassemia |
Influence on single trait. | Influence on multiple traits. |
Inheritance is criss-cross. | Inheritance is straight from both the parents to all the offsprings. |
Category of genetic disorder Haemophilia – Sex-linked disease Thalassemia – Autosomal recessive disease
Question 107. Which chromosomes carry the mutant genes causing thalassemia in humans? What are the problems caused by these mutant genes? (Delhi 2015) Or Write the type and location of the gene causing thalassemia in humans. State the cause and symptoms of the disease. How is sickle-cell anaemia different from this disease? (Foreign 2014) Answer: Thalassemia is an autosomal-linked recessive disease, which occurs due to either mutation or deletion of genes, resulting in reduced rate of synthesis of one of the globin chains of haemoglobin. It is associated with the mutation in chromosome 11 or 16 which code for p-chain and a – chain of haemoglobin, respectively. Haemoglobin is the oxygen carrying component of the red blood cells. It consists of two different proteins, an a and a p. If the body does not produce enough of either of these two proteins, the red blood cells do not form properly and cannot carry sufficient oxygen. This results in anaemia that begins in early childhood and lasts throughout the life. For sickle-cell anaemia, Refer to Answer No. 25.
Question 108. Name the phenomenon that leads to situations like ‘XO’ abnormality in humans. How do humans with ‘XO’ abnormality suffer? Explain. (Foreign 2012) Or Name a disorder, give the karyotype and write the symptoms a human suffers from as a result of monosomy of the sex chromosome. (Foreign 2011) Or (i) Name the genetic disorder in a human female having 44 + XO karyotype. Mention the diagnostic features of this disorder. (ii) Explain the cause of such chromosomal disorder. (Delhi 2011c) Answer: XO abnormality or monosomy of X-chromosome represents chromosomal disorder called Turner’s syndrome.
Non-disjunction is responsible for this chromosomal disorder. It is the phenomenon of failure of segregation of the members of homologous pairs of the chromosomes. Such disorder occurs due to the absence of one X-chromosome, i.e. 45 with XO (karyotype). The affected individual has underdeveloped feminine characters. Females are sterile and ovaries are rudimentary.
Question 109. (i) Sickle-cell anaemia in humans is a result of point mutation. Explain. (ii) Write the genotypes of both the parents, who have produced a sickle-celled anaemic offspring. (Delhi 2011) Answer: (i) Point mutation occurs due to change in a single base pair of DNA. Sickle-cell anaemia occurs due to defect caused by the single base substitution at the sixth codon of the P-chain of haemoglobin from GAG to GUG.
This causes substitution of glutamic acid by valine. The defective haemoglobin molecule undergoes polymerisation under low oxygen tension causing sickle-shaped red blood cells.
(ii) The parents must be heterozygotes, i.e. Hb A Hb s and Hb A Hb s to produce a sickle-celled anaemic offspring. Refer to Answer No. 25 and 35.
Question 110. Name a disorder, give the karyotype and write the symptoms where a human male suffers as a result of an additional X-chromosome. (Foreign 2011) Or Name the genetic disorder caused by an extra X-chromosome in a human male. State the diagnostic features of the individual suffering from it. (Delhi 2011C) Answer: It is a chromosomal disorder called Klinefelter’s syndrome, which occurs in males. The affected human males have XXY sex chromosome (47 chromosomes). Karyotype: 44 + XY Symptoms
Question 111. (i) Why are grasshopper and Drosophila said to show male heterogamety? Explain. (ii) Explain female heterogamety with the help of an example. (All India 2010) Or Explain the mechanism of sex-determination in insects like Drosophila and grasshopper. (All India 2010) Answer: (i) In male heterogamety, males produce two different types of gametes. In humans and Drosophila, the males have one X and Y chromosome, whereas in grasshopper, the male have only one X-chromosome (XO type). Thus, the males of these organisms show male heterogamety as they produce two types of gametes Either with or without X-chromosome Some gametes with X-chromosome and some with Y-chromosome.
(ii) In some organisms, females produce two different types of gametes. This is termed as female heterogamety. In birds and some reptiles, female has two different sex chromosomes (one Z and one W-chromosome) whereas male has a pair of same chromosome (a pair of Z-chromosome). (11/2)
Question 112. (i) Why are thalassemia and haemophilia categorised as Mendelian disorders? Write the symptoms of these diseases. Explain their pattern of inheritance in humans. (ii) Write the genotypes of the normal parents producing a haemophilic son. (All India 2015) Answer: (i) Thalassemia and haemophilia are categorised as Mendelian disorders because these disorders are due to alteration in a single gene. Also, they are transmitted to offspring through Mendelian principles of inheritance. Symptoms and pattern of inheritance are given below
(a) Thalassemia It is an autosome-linked recessive blood disorder characterised by defect in α, ß or δ-chain resulting in abnormal Hb molecule. Symptom Anaemia: Inheritance Two mutant alleles (one from each parent) must be inherited for an individual to be affected, i.e. homozygous. Heterozygous are carriers and may pass the mutant allele to their children.
(b) Haemophilia It is a sex-linked recessive disorder whose gene is located on X-chromosome. Symptom Prolonged clotting time and internal bleeding, even in a minor injury.
Inheritance The gene is present on X-chromosome, so it is inherited by males as they have a single X-chromosome. Affected males are said to be hemizygous. Females have 2 X-chromosomes, thus their possibility of being affected is rare as the mother of such female has to be at least carrier and father should be haemophilic.
Question 113. (i) Why are colour blindness and thalassemia categorised as Mendelian disorders? Write the symptoms of these diseases seen in people suffering from them. (ii) About 8% of human male population suffers from colour blindness whereas only about 0.4% of human female population suffers from this disease. Write an explanation to show how it is possible. (All India 2015) Answer: (i) The inheritance pattern of colour blindness is same as that of haemophilia. Refer to Answer No. 41.
(ii) Colour blindness is an X-linked recessive trait which shows transmission from carrier female progeny. In males, the defect can appear in heterozygous condition beacause males possess only one X-chromosome whereas in females, it appears in homozygous condition only, which is very rare. Thus, it is more common in males than females.
Question 114. (i) Explain the mechanism of sex-determination in humans. (ii) Differentiate between male heterogamety and female heterogamety with the help of an example of each. (All India 2013) Answer: (i) Refer to Answer No. 24.
(ii) A sex (male or female) is heterogametic, if it has two different sex chromosomes. Male heterogamety The female has two X-chromosomes (XX), while male has only one X-chromosome and at the time of gametogenesis the latter produces two types of gametes, 50% with X-chromosome, while other 50% without X-chromosomes. Heterogametic r tales are of two types
Heterogametic females are of two types
Question 115. (i) Why is haemophilia generally observed in human males? Explain the conditions under which a human female can be haemophilic. (ii) A pregnant human female was advised to undergo MTP. It was diagnosed by her doctor that the foetus she is carrying has developed from a zygote formed by an XX-egg fertilised by Y carrying sperm. Why was she advised to undergo MTP? (All India 2011) Answer: (i) The genes for haemophilia are present on X-chromosome. A male has only one X-chromosome and bears only one allele for the trait. He is hemizygous for the trait as Y-chromosome does not have a corresponding allele. A female contains two X-chromosomes. She has to be homozygous recessive to be haemophilic. It means her father must be a sufferer and mother must be either a carrier or sufferer to carry forward the disease.
(ii) The zygote will have XXY-chromosomes. It will develop into a male with Klinefelter’s syndrome. Such males are sterile and show feminine characters. That is why, female was advised to undergo MTP.
Question 116. (i) How does a chromosomal disorder differ from a Mendelian disorder? (ii) Name any two chromosomal aberration-associated disorders. (iii) List the characteristics of the disorders mentioned above that help in their diagnosis. (Delhi 2010) Answer: (i) Differences between chromosomal disorders and Mendelian disorders are
Chromosomal disorders | Mendelian disorders |
These are caused due to the absence or excess of one or more chromosomes or abnormal arrangement of one/more chromosomes. | These are due to alteration in a single gene. |
They are not transmitted as the affected individual is sterile. | They are transmitted to generations through Mendelian principles of inheritance. |
Example: Down’s syndrome, Turner’s syndrome. | Example: colour blindness, phenylketonuria. |
(ii) Chromosomal disorders Down’s syndrome and Klinefelter’s syndrome.
(iii) Down’s syndrome The affected individual is short statured with small round head, furrowed tongue and partially open mouth. Physical, psychomotor and mental development is also retarded.
Klinefelter’s syndrome It occurs in males, which show overall muscular development, but feminine development also occurs. Such individuals are sterile.
Question 117. Explain the causes, inheritance pattern and symptoms of any two Mendelian genetic disorders. (Delhi 2010) Answer: Two Mendelian genetic disorders are as follows
The affected individual lacks an enzyme phenylalanine hydroxylase that converts the amino acid phenylalanine into tyrosine. As a result, phenylalanine gets accumulated in brain and body and gets converted into phenyl pyruvate and other derivatives.
Symptoms Accumulation of these compounds in the brain causes mental retardation. They are also excreted in the urine due to poor absorption by kidney.
(ii) Individual Y-blood groups can be O or A. (iii) I A and I B when stay together, show the phenomenon of codominance and express themselves in the presence of each other. In heterozygous hybrid, when both alternative alleles coexist, both the alleles show their effect and result in the progeny with AB blood group. This is called codominance.
Question 120. Naresh, a haemophilia patient, forbades his daughter to marry Mohan who is also a haemophilia patient. Is Naresh right? Answer: Naresh is right because his daughter can be carrier of haemophilia disease (an X-linked disorder). If she marries a haemophilic person, there are 75% chances that their offspring will also suffer from haemophilia.
Question 121. Avantika’e doctor advised her to undergo MTP because through diagnostic tests she came to know that her foetus has XO chromosomes. Do you think Avantika should undergo MTP? Give reason. Answer: (i) Yes, Avantika should undergo MTP. (ii) The foetus contains XO chromosomes, i.e. one X-chromosome is lacking. It means that the baby will be suffering from Turner’s syndrome. Therefore, MTP is recommended.
Question 122. Prateek was rushed to a nearby hospital after an accident, which had caused too much blood loss. The hospital failed to supply O negative blood for transfusion. Asif, who was attending a patient there, heard about the situation and agreed to donate blood as he had the same blood group. Prateek’s mother initially refused but was later convinced by her daughter’s view. (i) Why cannot O positive blood be transfused into Prateek’s body? (ii) Human blood grouping is an example of? (iii) What values do you find in Prateek’s sister and Asif? Answer: (i) O + blood group contains antigen for Rh factor. Rh – blood lacks the antigen, so if the two blood mix, it will lead to clotting and thus, death of the patient. (ii) Multiple allelism. (iii) Prateek’s sister shows understanding of science and Asif believes in helping a person in need without thinking about which religion or caste he belongs to.
The following are practice questions for Chapter-5 of Class-XII Biology:-“Principle of Inheritance and Variation”. These questions are sourced from previous years board examinations question papers, sample papers issued by CBSE, NCERT exemplar and certain other sources.
VSA Type-I [1 Mark]
VSA Type-II [2 Mark]
SA Type [3 Mark]
LA Type [5 Mark]
Very Short Answer Type
Short answer type
very helpful for my test
sir can we get answers for above questions mainly for pedigree charts which i feel easy to understand
Very much helpful
Talk to our experts
1800-120-456-456
Class 12 biology chapter 5 important questions PDF provides the students with well-explained answers to the most important and frequently asked questions of the chapter, such that each of the students can get a more easy way of learning and understanding the chapter. This in turn would help them ace their exams. Class 12 biology principles of inheritance and variation important questions are important for the board as well as entrance exams purpose, such as NEET .
Also, check CBSE Class 12 Biology Important Questions for other chapters:
CBSE Class 12 Biology Important Questions | ||
Sl.No | Chapter No | Chapter Name |
1 | Chapter 1 |
|
2 | Chapter 2 |
|
3 | Chapter 3 |
|
4 | Chapter 4 |
|
5 | Chapter 5 | Principles of Inheritance and Variation |
6 | Chapter 6 |
|
7 | Chapter 7 |
|
8 | Chapter 8 |
|
9 | Chapter 9 |
|
10 | Chapter 10 |
|
11 | Chapter 11 |
|
12 | Chapter 12 |
|
13 | Chapter 13 |
|
14 | Chapter 14 |
|
15 | Chapter 15 |
|
16 | Chapter 16 |
|
Very Short Questions and Answers (1 Marks Questions)
1. Give any two reasons for the selection of pea plants by Mendel for his experiments.
Ans: The two reasons for the selection of pea plants by Mendel for his experiments are:
(i) Many varieties are present with contrasting forms of characters.
(ii) They can be easily cross-pollinated as well as self-pollinated.
2. Name any one plant that shows the phenomenon of incomplete dominance during the inheritance of its flower colour.
Ans: Dog flower or Snapdragon (Antirrhinum sp.) is the plant that shows the phenomenon of incomplete dominance during the inheritance of its flower colour.
3. Name the base change and the amino acid change, responsible for sickle cell anaemia.
Ans: The change in base GAG as GUG and substitution of Glutamic acid by valine is responsible for sickle cell anaemia.
4. Name the disorder with the following chromosome complement.
(i) 22 pairs of autosomes + X X Y
Ans: The name of disorders are:
(i) Klinefelter's Syndrome with chromosome complement as 22 pairs of autosomes + X X Y.
(ii) 22 pairs of autosomes + 21st chromosome + XY.
Ans: Downs syndrome with chromosome complement as 22 pairs of autosomes + 21st chromosome + XY.
5. A haemophilic man marries a normal homozygous woman. What is the probability that their daughter will be haemophilic?
Ans: When a haemophilic man marries a normal homozygous woman, is the probability of their daughter being haemophilic is $ 0 $%.
6. A test is performed to know whether the given plant is homozygous dominant or heterozygous. Name the test and phenotypic ratio of this test for a monohybrid cross.
Ans: A test cross is performed to know whether the given plant is homozygous dominant or heterozygous and 1:1 is the phenotypic ratio of the test cross for a monohybrid cross.
7. Name the phenomena that occur when homologous chromosomes do not separate during meiosis.
Ans: The name of the phenomenon is non – disjunction that occurs when homologous chromosomes do not separate during meiosis.
8. Name one trait each in humans & in drosophila whose genes are located on the sex chromosome.
Ans: The name of traits whose genes are located on the sex chromosome in humans is colourblindness and in drosophila is eye colour.
9. What is meant by aneuploidy?
Ans: Aneuploidy is the phenomenon of the existing or loss of one or more chromosomes due to failure in the separation of members of a homologous pair of chromosomes during meiosis.
10. What genetic principle could be derived from a monohybrid cross?
Ans: The Law of dominance is the genetic principle derived from a monohybrid cross.
11. Which one change is the cause of sickle–cell anaemia?
Ans: Sickle–cell anaemia is caused due to a point mutation at the 6th position in the B-chain of haemoglobin in which glutamic acid is replaced by valine.
12. What is a test cross?
Ans: A test cross is a cross in which offspring with a dominant phenotype is crossed with a homozygous recessive individual to determine the offspring’s genotype for the specific trait.
13. What is mutagen? Give an example?
Ans: The physical or chemical agents that cause mutations are called mutagen. For eg x-rays, CNBr etc.
14. What was the total number of varieties of garden pea which Mendel had taken to start his experiment?
Ans: The total number of fourteen varieties of a garden pea has been taken by Mendel to start his experiment.
15. Name any one plant & its feature that shows the phenomena of incomplete dominance?
Ans: Antirrhinum majus shows the phenomenon of incomplete dominance in flower colour.
1. Identify the sex of the organism as male or female in which the sex chromosome is found as
(i) ZW in birds
Ans: ZW in birds: Female
(ii) XY in Drosophila
Ans: XY in Drosophila: Male
(iii) ZZ in birds
Ans: ZZ in birds: Female
(iv) XO in grasshoppers
Ans: XO in grasshopper: Male
2. Mention two differences between Turner’s syndrome and Klinefelter's syndrome.
Ans: The two differences between Turner’s syndrome and Klinefelter's syndrome is as follows:
Turner’s syndrome | Klinefelter's syndrome |
The suffering individual is female. | The suffering individual is male. |
It has 45 chromosomes i.e., one X chromosome is less. | It has 47 chromosomes i.e., one extra X chromosome. |
3. The human male never passes on the gene for haemophilia to his son. Why is it so?
Ans: The human male never passes on the gene for haemophilia to his son because the gene for haemophilia is present on the X chromosome. A male has only one X chromosome which he receives from his mother and the Y chromosome from his father. The human male passes the X chromosome to his daughters or female progeny and not to the sons or male progeny.
4. Mention four reasons why Drosophila was chosen by Morgan for his experiments in genetics.
Ans: The four reasons for which Morgan has chosen Drosophila for his experiments in genetics are as follows:
(i) Drosophila has a very short life cycle i.e. of 2-weeks.
(ii) It can be grown easily in the laboratory.
(iii) In single mating it produces a large number of flies.
(iv) Many hereditary variations have been shown by males and females.
(v) It has only 4 pairs of chromosomes that are distinct in size and shape.
5. Differentiate between point mutation and frameshift mutations.
Ans: The difference between point mutation and frameshift mutation is as follows:
Point mutation | Frameshift mutation |
It arises due to change in a single base pair of DNA e.g., sickle cell anaemia. | It arises due to deletion or insertion or duplication or addition of one or two bases in DNA. |
6. Give any two similarities between the behaviour of genes (Mendel’s factor) during inheritance and chromosomes during cell division.
Ans: The two similarities between the behaviour of genes (Mendel’s factor) during inheritance and the behaviour of chromosomes during cell division are as follows:
(i) In diploid cells, the chromosomes are found in pairs like Mendelian factors.
(ii) The chromosomes of different homologous pairs are assorted independently into gametes during meiosis. This is at random showing parallelism with mendelian factors.
7. Which law of Mendel is universally accepted? State the law?
Ans: Mendel’s law of segregation is universally accepted. The law states that – “The two alleles of a gene remain separate and do not contaminate each other in F1 or the hybrid. At the time of gamete formation, two alleles get separated and pair into different gametes”.
8. How will you find out whether a given plant is homozygous or heterozygous?
Ans: To test whether a plant is homozygous or heterozygous, a test cross is performed in which an individual is crossed with homozygous recessive for the trait. If a plant is heterozygous, the progeny of testcross consists of tall and dwarf plants in the ratio of 1:1.
If the plant is homozygous, the progeny of testcross will have all tall plants.
9. Why do sons of a haemophilic father never suffer from this trait?
Ans: Since haemophilic is a sex-linked character and the gene responsible for haemophilia is present on the X chromosome, it shows criss-cross inheritance i.e., the X chromosome is transferred from father to his daughter and not to his son. Therefore the son of a haemophilic father is never haemophilic.
10. How is the child affected if it has grown from the zygote formed by an XX-egg fertilized by Y-carrying sperm? What do you call this abnormality?
Ans: If a child has grown from the zygote formed by XX-egg fertilized by Y-sperm, the child will suffer from Klinefelter syndrome and he will have XXY genotype. The Klinefelter syndrome is characterized by the child’s development of prominent feminine characters such as tall stature with feminised physique, breast development, pubic hair pattern, poor beard growth, & sterility.
11. The map distance between a certain organisms genes A and B is 4 units, between B and C is 5 units and between C and D is 8 units. Which one of the gene pairs will show more recombination frequency? Give reason.
Ans: Here, C and D will show maximum gene recombination because genes that are linked more closely are having the least frequency of recombination and vice versa.
12. Give the chromosomal constitution and related sex in each of the following:-
(i) Turner syndrome
Ans: Turner syndrome – In Turner syndrome XO is the chromosomal constitution and is female containing 45 chromosomes and lacking in one X-Chromosome.
(ii) Klinefelter syndrome
Ans: Klinefelter syndrome – In Klinefelter syndrome XXY is the chromosomal constitution and is male containing 47 chromosomes and has one extra X-chromosome.
13. What is pedigree analysis? How is it useful?
Ans: The analysis of case history about the inheritance of a specific trait in several generations of a family is named pedigree analysis. It provides a robust tool that's utilized to trace the inheritance of specific traits or abnormalities or diseases.
14. What are multiple alleles? Give an example?
Ans: The presence of more than two alleles of a trait is called multiple alleles. E.g. in human beings, four types of blood groups are recognized and their different alleles ${ I }^{ A }$, ${ I }^{ B }$, and ${ I }^{ O }$ of a gene determines the phenotype of four blood groups.
1. A woman with an O blood group marries a man with an AB blood group
(i) work out all the possible phenotypes and genotypes of the progeny.
Ans: When a woman with an O blood group marries a man with an AB blood group then-
All the possible phenotypes of the progeny include blood groups A and B and genotypes of the progeny will be${ I }^{ A }{ i }$and${ I }^{ B }{ i }$ because blood group AB has alleles ${ I }^{ A }{ I }^{ B }$ and blood group O has ${ i }{ i }$ which on the cross gives both types of blood groups A and B while the genotype of progeny will be ${ I }^{ A }{ i }$ and ${ I }^{ B }{ i }$.
Father’s genes: ${ I }^{ A }{ I }^{ B }$
Mother’s genes: ${ i }{ i }$
Therefore, the cross will be
Mother’s genes→ Father’s genes↓ | ${ i }$ | ${ i }$ |
${ I }^{ A }$ | ${ I }^{ A }{ i }$ | ${ I }^{ A }{ i }$ |
${ I }^{ B }$ | ${ I }^{ B }{ i }$ | ${ I }^{ B }{ i }$ |
(ii) Discuss the kind of dominance in the parents and the progeny in this case.
Ans: In the above-mentioned case, the kind of dominance in the parents and the progeny is that they ( ${ I }^{ A }$ and ${ I }^{ B }$) are equally dominant or co-dominant. In the case of multiple allelism, a gene I exists in three allelic forms, ${ I }^{ A }$, ${ I }^{ B }$ and ${ i }$.
2. Explain the cause of Klinefelter’s syndrome. Give any four symptoms shown by the sufferer of this syndrome.
Ans: The presence of an extra chromosome in males i.e., XXY is the cause of Klinefelter’s syndrome. The symptoms found in the sufferer of Klinefelter’s syndrome are the development of breast, female type pubic hair pattern, poor beard growth, underdeveloped testes, and tall stature with the feminized physique.
3. In Mendel's breeding experiment on garden peas, the offspring of the ${ F }_{ 2 }$ generation are obtained in the ratio of ${ 25 }$% pure yellow pod, ${ 50 }$% hybrid green pods and ${ 25 }$% green pods. State
(i) which pod colour is dominant
Ans: In Mendel's breeding experiment on garden peas, Green pod colour is dominant in the offspring of the ${ F }_{ 2 }$ generation.
(ii) The Phenotypes of the individuals of the ${ F }_{ 1 }$ generation.
Ans: Green pod colour is the phenotype of the individuals of the ${ F }_{ 1 }$ generation.
(iii) Workout the cross.
Ans: The cross will be shown as:
Phenotypic ratio 3: 1
Genotypic ratio 1: 2: 1
4. In Antirrhinum majus a plant with red flowers was crossed with a plant with white flowers. Work out all the possible genotypes and phenotypes of ${ F }_{ 1 }$ and ${ F }_{ 2 }$ generations, comment on the pattern of inheritance in this case?
Ans: When Antirrhinum majus, a plant with red flowers, was crossed with a plant with white flowers, the ${ F }_{ 1 }$ hybrid was pink i.e. a middle colour between red and white will appear which indicates that both red and white are incompletely dominant. When ${ F }_{ 1 }$ individuals were self-pollinated, the ${ F }_{ 2 }$ generation consists of red, pink and white flowers that appear in the ratio of 1:2:1 respectively. The pattern of inheritance of flower colour in snapdragon or Antirrhinum majus is an example of incomplete dominance.
5. A red-eyed male fruit fly is crossed with a white-eyed female fruit fly. Work out the possible genotype and phenotype of ${ F }_{ 1 }$ and ${ F }_{ 2 }$ generation. Comment on the pattern of inheritance in this cross?
Ans: When a red-eyed male fruit fly is crossed with a white-eyed female fruit fly, the offspring will have both white-eyed male & red-eyed female in the ratio of 1:1 in the ${ F }_{ 1 }$ generation. In the ${ F }_{ 2 }$ generation, ${ 50 }$% females will be red-eyed and ${ 50 }$% will be white-eyed, similarly, in males ${ 50 }$% will be red-eyed and ${ 50 }$% will be white-eyed. This result indicates that in fruitflies males transmit their sex-linked characters to their grandson through their daughter; such type of inheritance is called criss-cross inheritance.
6. A man with AB blood group marries a woman with O group blood.
(i) Work out all the possible phenotypes and genotypes of the progeny.
Ans. When a man with AB blood group marries a woman with O group blood then, Half the progeny will have blood group A with genotype ${ I }^{ A } { I }^{ O }$ & half the progeny will have blood group B with genotype ${ I }^{ B } { I }^{ O }$.
(ii) Discuss the kind of domination in parents and progeny in this case.
Ans: In this case both the genes ${ I }^{ A }$ and ${ I }^{ B }$ are dominant over the ${ I }^{ O }$ gene therefore the progeny shows either blood group A or B. Since in parents both the dominant genes are present together this phenomenon is called codominance.
7. In a cross made between a hybrid tall and red plant (TtRr) with dwarf & white flower (ttrr). What will be the genotype of plants in the ${ F }_{ 1 }$ generation?
Ans: When a cross is made between a hybrid tall and red plant (TtRr) with dwarf and white flower (ttrr) plants then TtRr, ttRr, ttRr, and ttRr will be the genotypes of the plants develop in the ${ F }_{ 1 }$ generation.
8. How sex is determined in human beings?
Ans: In human beings, all the females bear a pair of X-chromosomes while males have one X-chromosome and one Y-chromosome which is comparatively smaller in size. Thus, in a cross between males and females, there is an equal probability of males and females in progeny and sex is determined based on the presence of a Y-chromosome in the progeny. If a Y-chromosome is present it is male otherwise it is a female child.
9. A smooth seeded and red-flowered pea plant (SsRr) is crossed with a smooth seeded and white-flowered pea plant (Ssrr). Determine the phenotypic and genotypic ratio in ${ F }_{ 1 }$ progeny?
Ans: When a cross is done between smooth seeded and red-flowered pea plant (SsRr) along with a smooth seeded and white-flowered pea plant (Ssrr) then 1:3:3:1 will be the phenotypic ratio in ${ F }_{ 1 }$ progeny i.e., rough seed and red flower =1, smooth seed and red flower =3, smooth seed and white flower =3, and rough seed and white flower =1. The genotypic ratio is ${ F }_{ 1 }$ progeny will be 1:2:1:2:1:1 i.e., SSRr =1, SsRr =2, SSrr =1, Ssrr =2, ssRr =1, and ssrr =1.
1. A dihybrid heterozygous round, yellow seeded garden pea (Pisum sativum) was crossed with a double recessive plant.
(i) What type of cross is this?
Ans: When a dihybrid heterozygous round- yellow seeded garden pea (Pisum sativum) was crossed with a double recessive plant then, this type of cross is known as a dihybrid test cross.
(ii) Work out the genotype and phenotype of the progeny.
Ans: Below given is the Work out the genotype and phenotype of the progeny-
(iii) What principle of Mendel is illustrated through the result of this cross?
Ans: Through the result of the dihybrid test cross Mendel’s principle of independent assortment is illustrated.
2. In dogs, barking trait is dominant over silent trait & erect ears are dominant over drooping ears. What is the expected phenotypic ratio of offspring when dogs heterozygous for both the traits are crossed?
Ans: When dogs are heterozygous for both (barking/silent trait and erect ears/drooping ears) the traits are crossed then the expected phenotypic ratio of offspring will be 9 : 3 : 3: 1 where traits for barking & erect ears = 9, barking & drooping ears =3, silent & erect ears = 3, and silent & drooping ears =1.
3. Differentiate between dominance, codominance and incomplete dominance with one example each.
Ans: The differences between dominance, codominance and incomplete dominance with one example are as follows:
Dominance | Codominance | Incomplete dominance |
When a cross is made between two characters in which one character is completely dominant over the other character in the progeny, this phenomenon is called dominance. | If the two equally dominant genes are present together, both of them will be equally expressed, this phenomenon is called codominance. | When a cross is made between two characters of which none of them is completely dominant then an intermediate character develops in the progeny, this phenomenon is called Incomplete dominance. |
For eg. When the true-breeding tall pea plant is crossed with the true-breeding dwarf pea plant, all the plants in the ${ F }_{ 1 }$ generation are tall; this shows that the tall character is dominant over dwarf in the progeny. | For eg. alleles of the blood group, ${ I }^{ A }$ and ${ I }^{ B }$ are dominant over ${ I }^{ O }$ but when both the alleles are present together, both of them will equally express and form a phenotype AB. | For eg. when a cross is made between a red flower & a white flower in a snapdragon flower an intermediate pink colour appears in the progeny. |
|
4. A dihybrid heterozygous tall and yellow pea plant was crossed with the double recessive plant.
(i) What type of cross is this?
Ans: When a dihybrid heterozygous tall and yellow pea plant was crossed with the double recessive plant then, this type of cross is known as a test cross.
(ii) Work out the genotype & phenotype of progeny.
Ans: Below given is the work out the genotype & phenotype of progeny-
Ans: Through the result of testcross Mendel’s Principle of Independent Assortment is illustrated. According to the principle, in the inheritance of contrasting characters, the factors of each pair of characters segregate independently of the factors of the other pair of characters.
Vedantu has created a PDF of important questions on the principles of inheritance and variation in Class 12 biology.
The PDF provides a simplified explanation of major topics, making it easier for students to understand and clear their doubts.
It offers a wholesome understanding of the chapter, helping students ace their biology exams.
The PDF is available for free download on Vedantu's platform, making education accessible to all students.
The questions in the PDF cover all the major parts and points of the chapter, serving as a summary for students.
It provides a basic idea of the answer-writing pattern in board exams, aiding students in exam preparation.
The PDF can be used as last-minute revision notes to enhance remembrance of the topics.
It is easily accessible and portable, allowing students to study on any device or take printouts for convenience.
Vedantu also offers live classes, which further support students in learning and understanding the concepts effectively.
Heredity can be defined as a mechanism of transfer heritable traits and genes from parents to their progeny.
Genetics is the branch of biology that discusses inheritance and variation concepts and mechanisms.
Inheritance is the basis of inheritance and characteristics are passed down from the parents to the offspring through this process. The continuity of the gene pool is preserved by the inheritance mechanism.
Genes are found on chromosomes and are the fundamental unit of inheritance.
Among individuals of one species, variation exists. Variation can happen due to recombination, crossing over, environmental effects, and mutation on the expression of genes that are found on chromosomes.
1. Law of Dominance States That:
Characters are regulated by discrete units that are called factors.
Factors often emerge in pairs.
One member of a pair dominates the other in a distinct pair of factors.
2. Law of Segregation States That:
Each of the alleles gets separated during the process of meiosis, at the time of gamete formation. In this process, there occurs no blending and also the characters are found to be passed to distinct gametes. The production of homozygotes can be done using only a single kind of gametes whereas heterozygotes are produced with the help of two distinct kinds of gametes.
3. Law of Independent Assortment States That:
The law specifies that 'when two pairs of characteristics are mixed in a hybrid, the segregation of one pair of characters is independent of the other pair of characters.' Two new combinations are produced in Dihybrid cross, round green & wrinkled yellow due to an independent assortment of seed color, i.e. yellow and green and seed shape characteristics, i.e. round, wrinkled.
Sutton and Boveri accepted the findings of Mendel and claimed that the carrier of genes is chromosomes.
Chromosomes exist as a homologous pair and a gene's two alleles are found at the same location on the homologous pair of chromosomes.
In the course of gamete formation, homologous chromosomes differentiate during meiosis.
Chromosomes independently segregate and assort.
Gametes pair up and produce the progenies with a diploid number of chromosomes, which are similar to the parents. The fusion of gametes occurs during fertilization.
Morgan worked extensively on fruit flies, Drosophila melanogaster, and gave experimental arguments to confirm the chromosomal theory of inheritance.
The physical association of chromosome-located genes is known as linkage.
In a dihybrid cross, If two of the genes are closely related or situated on the very same chromosome, then it is observed that the parental combination is way more common than recombinants or non-parental combinations.
The recombination and linkage do vary on the distance present between the pair of genes. As the distance between the genes increases, the probability of recombination also increases.
In various species, there are various sex determination mechanisms involved.
First, Henking noticed the X chromosome and called it the X body.
The chromosomes that determine sexual character formation are referred to as sex chromosomes and the remaining chromosomes are referred to as autosomes.
If the male develops two distinct forms of gamete then It is classified as male heterogamety. Examples may include grasshoppers, humans, drosophila, etc.
If the female develops two distinct forms of gamete then It is termed as female heterogamety. Examples may include birds.
Any modification in the DNA sequence is considered a mutation. Viable mutations are observed to undergo inheritance from one generation to another.
This process of alteration in the DNA sequence might affect both the genotype and an organism's phenotype.
It is associated with different disorders, although not all mutations are harmful.
The mutation results in modifications such as deletion, addition, replication, replacement, etc. The significant cause of cancer is mutation.
Genetic disorders can usually be divided into two groups, Mendelian and Chromosomal disorders.
1. Mendelian Disorders:
Mendelian disorders occur due to single gene modification.
As per Mendel's rule, it follows the same inheritance pattern.
Pedigree Analysis can be used to know the pattern of inheritance and also decide whether the trait is dominant or recessive.
Sickle cell anaemia, Muscular dystrophy, Colour blindness, Thalassemia,Cystic fibrosis, Phenylketonuria are few of the examples of mendelian disorders.
2. Chromosomal Disorders:
Chromosomal diseases are diseases that occur due to chromosomes’ absence, excess, or irregular arrangement.
There are two types of chromosomal disorders:
Aneuploidy - Gain or loss of a chromosome or more. It occurs due to the chromatid segregation failure during meiosis anaphase.
Polyploidy - It is commonly present in plants. This occurs in an increase in the number of chromosomes.
Examples of chromosomal disorders may include Turner’s syndrome, Down's syndrome, and others.
Class 12 biology principles of inheritance and variation important questions covered all the crucial points. We discussed about Mendel’s Laws of Inheritance, Chromosomal Theory of Inheritance, Linkage and Recombination, Mutation, Sex Determination and Genetic Disorders. All these concepts are highly important from both the exam point of view and the entrance exams.
CBSE Class 12 Biology Study Materials |
|
|
|
|
|
The principle of inheritance and variation is a fundamental concept in biology that explores how traits are passed from one generation to another and the factors that contribute to genetic diversity. Vedantu's collection of important questions on this topic provides a valuable resource for Class 12 biology students to enhance their understanding and preparation for exams. These questions cover a wide range of topics, including Mendelian genetics, sex determination, genetic disorders, DNA replication, and genetic engineering. By practicing these questions, students can reinforce their knowledge, improve their problem-solving skills, and gain confidence in tackling biology examinations. Vedantu's comprehensive question bank is a valuable tool for students aiming to excel in the principle of inheritance and variation.
Q1. Why did Morgan choose Drosophila as the Experimental Material for his Studies in Genetics?
Ans: The reasons for Morgan choosing Drosophila as the experimental material for conducting studies in genetics include:
Drosophila has a very short life cycle of only two weeks
It can be easily grown under laboratory conditions
In a single mating, Drosophila can produce a large number of offsprings
Drosophila comprises of only four pairs of chromosomes that are distinct in size and shape
The male and female Drosophila display a wide range of heredity variations
Q2. What are the differences between Klinefelter’s and Turner’s Syndrome?
Ans: Both Turner’s and Klinefelter’s syndrome display anomaly in the number of sex chromosomes. However, there are certain differences between the two syndromes that are highlighted below.
Turner’s syndrome is characterised by the deficit of an X chromosome. This occurs in female individuals and the total number of chromosomes in the individual is 45. Turner’s syndrome is denoted by 45, X0.
Klinefelter’s syndrome, on the other hand, is the presence of an extra X chromosome in males. The individual affected here is male and the total number of chromosomes is 47. This syndrome is denoted by 47, XXY
Q3. Why does the Human Male never Pass the Gene for Haemophilia to his Son?
Ans: Haemophilia is an X-chromosomal genetic disorder, i.e., the haemophilic gene on humans is present on the X chromosome. This disorder impairs the ability of the human body to clot blood, in case of an injury. A human male has only one X chromosome, which is inherited from the mother during the process of reproduction while the Y chromosome is obtained from the father. As such, the human male the X chromosome on to the daughters, (characterised by XX) but never on to the sons (characterised by XY).
Q4. Why should you refer to important questions of Biology Class 12 Chapter 5 by Vedantu?
Ans: The Class 12 Biology Chapter 5 Principles of Inheritance and Variation Important Questions by Vedantu have been handpicked by the subject experts. While studying the chapter or undergoing a quick recap before the exams the important questions of Biology Class 12 Chapter 5 can prove to be highly beneficial. These important questions encompass all the important topics of the chapter. Moreover, the important questions have also been arranged according to the marks they carry and provided with adept answers. So, go through the important questions of Class 12 Biology Chapter 5 today!
Q5. How are the alleles of a gene different from each other? What is its importance?
Ans: As discussed in Chapter 5 Principles of Inheritance and Variation of Class 12 Biology, the pair of alleles of a gene are different from each other even though their difference is not observed in the phenotype or the traits such as blood type and eye colour. The difference is very minute in the form of the absence or presence of a molecule (mutations in a segment DNA). The Alleles are significant because it is through their presence that variations are visible in organisms.
Q6. What is the study of inheritance and variation called?
Ans: The chapter discusses that the study of inheritance and variation is called Genetics. In simple words, one of the aspects of genetics involves the scientific study of variations that are inherited from the parent to the progeny. The concept of inheritance and variation can be understood with the help of a common example. Many times we notice that children have several features that are similar to their parents because they have 'inherited' these features from their parents. Similarly, the children don't look exactly identical to their parents because of a 'variation' in their genes.
Q7. How far are the genes and environment responsible for expression of a particular trait?
Ans: The chapter explains that both the genes and environment are responsible for the expression of traits. The inherited genes act as messages in our DNA which play a major role in determining the traits of an individual and the expression of these traits. Similarly, environmental factors such as food, temperature, humidity levels, oxygen, light etc. influence the expression of the traits present in an organism's genes. The environmental factors also affect an animal's phenotype or observable traits such as blood type, height and eye colour.
Q8. What is variation according to Chapter 5 Principles of Inheritance and Variation of Class 12 Biology?
Ans: As discussed in the chapter, the organisms, even from the same species are not identical and have several differences in physiology, genetics, behavioural traits, and so on. These differences that make the progeny different from the parent within the same species is referred to as Variation. Thus, in simple words, Variation is the process through which characters are passed to the progeny from the parent. Variation occurs due to several reasons such as environmental factors, reshuffling of genes, mutation and recombination.
These solutions are available on Vedantu's official website( vedantu.com ) and mobile app free of cost.
Q9. What are the important questions of Chapter 5 Principles of Inheritance and Variation of Class 12 Biology?
Ans: You can access important questions of Chapter 5 Principles of Inheritance and Variation of Class 12 Biology by referring to Vedantu's Important Questions for this chapter. By thoroughly preparing these questions, you will be able to cover the most important topics of the chapter and score well. These questions have been prepared after analyzing the previous year questions and the latest syllabus. Thus, these questions will help you to clear the Biology exam with flying colours.
Cbse study materials.
In Class 12 Boards there will be Case studies and Passage Based Questions will be asked, So practice these types of questions. Study Rate is always there to help you. Free PDF Downloads of CBSE Class 12 Biology Chapter 6 Molecular Basis of Inheritance Case Study and Passage Based Questions with Answers were Prepared Based on the Latest Exam Pattern. Students can solve Class 12 Biology Case Study Questions Molecular Basis of Inheritance to know their preparation level.
Join our Telegram Channel, there you will get various e-books for CBSE 2024 Boards exams for Class 9th, 10th, 11th, and 12th.
In CBSE Class 12 Biology Paper, There will be a few questions based on case studies and passage-based as well. In that, a paragraph will be given, and then the MCQ questions based on it will be asked.
Here, we have provided case-based/passage-based questions for Class 12 Biology Chapter 6 Molecular Basis of Inheritance
Case Study/Passage-Based Questions
Case Study 1: In prokaryotes, DNA is circular and present in the cytoplasm but in eukaryotes, DNA is linear and mainly confined to the nucleus. DNA or deoxyribonucleic acid is a long polymer of nucleotides. In 1953, the first correct double helical structure of DNA was worked out by Watson and Crick. Based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin. It is composed of three components, i.e., A phosphate group, deoxyribose sugar, and a nitrogenous base. Different forms of DNA are B-DNA, Z-DNA, A-DNA, C-DNA, and D-DNA.
(i) Name the linkage present between the nitrogen base and pentose sugar in DNA.
(a) Phosphodiester bond | (b) Glycosidic bond | (c) Hydrogen bond | (d) None of these |
Answer: (b) Glycosidic bond
(ii) The double helix structure of DNA was proposed by
(a) James Watson and Francis Crick | (b) Earwin Chargaff | (c) Federick Griffith | (d) Hershey and Chase |
Answer: (a) James Watson and Francis Crick
(iii) The double chain of B-DNA is coiled in a helical fashion. The spiral twisting of the B-DNA duplex produces
(a) right and left part | (b) major and minor grooves | (c) upper and lower sides | (d) linear and circular part. |
Answer: (b) major and minor grooves
(iv) Assertion: The two strands of DNA helix have a uniform distance between them. Reason: A large-sized purine is always paired opposite to a small-sized pyrimidine.
(a) Both assertion and reason are true and reason is the correct explanation of assertion. | (b) Both assertion and reason are true but reason is not the correct explanation of assertion. |
(c) Assertion is true but reason is false. | (d) Both assertion and reason are false. |
Answer: (a) Both assertion and reason are true and reason is the correct explanation of assertion
(v) Which of the following describes the structure of B-DNA?
(a) Parallel | 5 |
(b) Anti-parallel | 10 |
(c) Parallel | 15 |
(d) Anti-parallel | 20 |
Answer: (b)
Case Study 2: The process of translation requires the transfer of genetic information from a polymer of nucleotides to synthesize a polymer of amino acids. The relationship between the sequence of amino acids in a polypeptide and the nucleotide sequence of DNA or mRNA is called genetic code. George Gamow suggested that in order to code for all the 20 amino acids, code should be made up of three nucleotides.
What is the process by which a polymer of nucleotides is used to synthesize a polymer of amino acids? A) Replication B) Transcription C) Translation D) Mutation
What is the relationship between the sequence of amino acids in a polypeptide and the nucleotide sequence of DNA or mRNA known as? A) Genetic Translation B) Genetic Mutation C) Genetic Replication D) Genetic Code
Who suggested that the genetic code should be made up of three nucleotides? A) James Watson B) Francis Crick C) George Gamow D) Rosalind Franklin
How many nucleotides are required to code for one amino acid in the genetic code? A) One B) Two C) Three D) Four
What is the main reason that three nucleotides are used to code for each amino acid? A) To ensure replication accuracy B) To allow for more combinations and code for all 20 amino acids C) To facilitate faster transcription D) To prevent mutations
Which of the following molecules carries the genetic information from DNA to the ribosome for translation? A) tRNA B) rRNA C) mRNA D) DNA
Hope the information shed above regarding Case Study and Passage Based Questions for Class 12 Biology Chapter 6 Molecular Basis of Inheritance with Answers Pdf free download has been useful to an extent. If you have any other queries about CBSE Class 12 Biology Molecular Basis of Inheritance Case Study and Passage Based Questions with Answers, feel free to comment below so that we can revert back to us at the earliest possible. By Team Study Rate
The last lesson summary class 12 english pdf, [pdf] download class 12 biology previous year questions pdf for cbse class 12 biology, class 12 physics case study questions of chapter 14 semiconductor electronics, leave a reply cancel reply.
Save my name, email, and website in this browser for the next time I comment.
This site uses Akismet to reduce spam. Learn how your comment data is processed .
No thanks, I’m not interested!
Free pdf download.
SHARING IS CARING If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.
An important topic included in the Class 12 Biology subject is Principles of Inheritance and Variation. You must be thorough with this chapter as various questions are asked from it in the board exam. For your assistance, we provide the Principles of Inheritance and Variation class 12 important questions with solutions on the SelfStudys website. With the practice of these questions on a daily basis, you can develop different problem-solving strategies to tackle them in an effective manner.
For several reasons, solving the class 12 Principles of Inheritance and Variation important questions plays a significant role during exam preparation. A few reasons to solve these questions are mentioned in detail below.
In this section, we are discussing the features of Class 12 Biology Principles of Inheritance and Variation Important Questions PDF that will help students like you to better understand why the PDF provided here is the best to use.
Here’s a step-by-step process to download the Class 12 Principles of Inheritance and Variation Important Questions with Answers PDF from our website.
Note: You need to Log In or Sign Up on the SelfStudys website first in order to complete the entire above-mentioned process.
One can use important questions for Class 12 Biology Principles of Inheritance and Variation PDF in whatever way they want. However, there are certain ways that we think are a good way to utilize the important questions for the Class 12 Biology Principles of Inheritance and Variation PDF.
Once a Class 12 student has studied the lesson completely can go for the important questions to practice. But, there are a few times when utilizing the important questions for class 12 Biology Principles of Inheritance and Variation PDF can help significantly.
There are certain points that students should take care of when using Principles of Inheritance and Variation Class 12 Important Questions PDF. Those points are mentioned below:
Various study materials such as previous year's question papers, sample question papers, CBSE Class 12 Biology Syllabus, and several other study resources are used to prepare the Principles of Inheritance and Variation Class 12 Important Questions with Solutions PDF.
While solving the CBSE Class 12 Principles of Inheritance and Variation important questions if a student feels stuck, they can use the following methods to deal with them.
Provide prime members with unlimited access to all study materials in PDF format.
Allow prime members to attempt MCQ tests multiple times to enhance their learning and understanding.
Provide prime users with access to exclusive PDF study materials that are not available to regular users.
Done mcqs - principles of inheritance and variation total questions - 195.
question_answer 1) Two crosses between the same pair of genotypes of phenotypes in which the sources of the gametes are reversed in one cross is known as:
A) Test cross done clear
B) Dihybrid cross done clear
C) Reverse cross done clear
D) Reciprocal cross done clear
question_answer 2) The total number of progenies obtained through dihybrid cross of Mendel is 1280 in F2 generation. How many are recombinants?
A) 240 done clear
B) 360 done clear
C) 480 done clear
D) 720 done clear
What is shown in the following figure? |
A) Steps in making a selfing in a pea plant done clear
B) Steps in making a cross in a lotus plant done clear
C) Steps in making a cross in a pea plant done clear
D) Steps in making a cross in a rose plant done clear
question_answer 4) In Mendel's experiments with garden pea, round seed shape (RR) was dominant over wrinkled seeds (rr), yellow cotyledon (YY) was dominant over green cotyledon (yy). What are the expected phenotypes in the \[{{F}_{2}}\] generation of the cross \[RRYY\text{ }\times \text{ }rryy\text{ }?\]
A) Only round seeds with green cotyledon done clear
B) Only wrinkled seeds with yellow cotyledons done clear
C) Only wrinkled seeds with green cotyledons done clear
D) Round seeds with yellow cotyledons, and wrinkled seeds with yellow cotyledons done clear
question_answer 5) How many different kinds of gametes will be produced by a plant having the genotype AA Bb CC ?
A) Three done clear
B) Four done clear
C) Nine done clear
D) Two done clear
question_answer 6) The possible blood group of children born to parents having A and AB groups are :
A) 0, A done clear
B) A, B, AB done clear
C) 0, A, B done clear
D) 0, A, B, AB done clear
question_answer 7) In Mirabilis jalapa, the number of \[{{F}_{2}}\] red flowered plants in a cross of red flowered x white flowered would be :
A) 1 done clear
B) 2 done clear
C) 3 done clear
D) 4 done clear
What type of cross is shown in the following figure? |
A) Diagrammatic representation of dihybrid cross done clear
B) Diagrammatic representation of trihybrid cross done clear
C) Diagrammatic representation of monohybrid cross done clear
D) Diagrammatic representation of test cross done clear
question_answer 9) A common test to find the genotype of a hybrid is by :
A) Crossing of one \[{{F}_{2}}\] progeny with female parent done clear
B) Studying of sexual behaviour of \[{{F}_{1}}\] progenies done clear
C) Crossing of one \[{{F}_{1}}\] progeny with male parent done clear
D) Crossing of one \[{{F}_{2}}\] progeny with male parent done clear
question_answer 10) One of the parents of a cross has mutation in its mitochondria. In that cross, the parent is taken as male. During segregation of \[{{F}_{2}}\] progenies that mutation is found in :
A) One third of the progenies done clear
B) None of the progenies done clear
C) All of the progenies done clear
D) Fifty per cent of the progenies done clear
question_answer 11) In the ABO system of blood groups, if both antigens are present but no antibody, the blood group the individual would be :
A) B done clear
B) 0 done clear
C) AB done clear
D) A done clear
question_answer 12) Extranuclear inheritance is a consequence of presence of genes in :
A) Mitochondria and chloroplasts done clear
B) Endoplasmic reticulum and mitochondria done clear
C) Ribosomes and chloroplasts done clear
D) Lysosomes and ribosomes done clear
question_answer 13) Which one of the following characters studied by Mendel in garden pea was found to be dominant?
A) Green seed colour done clear
B) Terminal flower position done clear
C) Green pod colour done clear
D) Wrinkled seed done clear
question_answer 14) In a given plant red colour (R) of fruits is dominant over white fruit (r); tallness (T) is dominant over dwarfness (t). If a plant with genotype RRTt is crossed with a plant of genotype rrtt, what will be the percentage of tall plants with red fruits in the next generation?
A) 100% done clear
B) 25% done clear
C) 50% done clear
D) 75% done clear
question_answer 15) If a dwarf pea plant was treated with gibberellic acid, it became a tall, as tall pea plants. If these pea plants are crossed with pure tall pea plants, what will be the phenotypic ratio in \[{{F}_{1}}\]generation?
A) All dwarf plants done clear
B) 50% tall and 50% dwarf plants done clear
C) 75 % tall and 25 % dwarf plants done clear
D) 100% tall plants done clear
question_answer 16) Red (dominant) flowered heterozygous crossed with white flower :
A) \[350\text{ }-\text{ }red\text{ }:\text{ }350\text{ }\tilde{\ }\text{ }white\] done clear
B) \[450\text{ }-\text{ }red\text{ }:\text{ }250\text{ }\tilde{\ }\text{ }white\] done clear
C) \[380\text{ }-\text{ }red\text{ }:\text{ }250\text{ }\tilde{\ }\text{ }white\] done clear
D) None of the above done clear
question_answer 17) A tall plant was grown in nutrient deficient soil and remained dwarf. When it is crossed with dwarf plant then :
A) All hybrid plants are dwarf done clear
B) All hybrid plants are tall done clear
C) 50% tall and 50% of dwarf done clear
D) 75% tall and 25% dwarf done clear
question_answer 18) A pure tall and a pure dwarf plant were crossed to produce offspring. Offsprings were self crossed, then find out the ratio between true breeding tall to true breeding dwarf?
A) 1 : 1 done clear
B) 3 : 1 done clear
C) 2 : 1 done clear
D) 1 : 2 : 1 done clear
question_answer 19) Cross between unrelated group of organisms is called :
A) Hybrid done clear
B) Test cross done clear
C) Back cross done clear
D) Heterosis done clear
Cytoplasmic inheritance is due to : |
(1) Mitochondria and Chloroplast |
(2) Cilia and Flagella |
(3) Cytoplasmic particles |
(4) Cell wall and Cell coat |
A) 1, 2 and 3 are correct done clear
B) 1 and 2 are correct done clear
C) 2 and 4 are correct done clear
D) 1 and 3 are correct done clear
question_answer 21) Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration is called :
A) Reciprocal cross done clear
C) Dihybrid cross done clear
D) Back cross done clear
What is depicted in the following cross? |
A) Diagrammatic representation of test cross done clear
B) Diagrammatic representation of out cross done clear
C) Diagrammatic representation of reverse cross done clear
D) Diagrammatic representation of dihybrid cross done clear
question_answer 23) The phenotypic ratio in the \[{{F}_{2}}\] generation of a dihybrid cross is :
A) 9 : 3 : 3 : 1 done clear
B) 1 : 2 : 2 : 4 : 1 : 2 : 1 : 2 : 1 done clear
C) 7 : 1 : 1 : 7 done clear
D) 1 : 2 : 3 : 4 done clear
question_answer 24) A woman is married for the second time. Her first husband was ABO blood type A, and her child by that marriage was type O. Her new husband is type B and their child is type AB. What is the woman's ABO genotype and blood type?
A) \[{{I}^{A}}{{I}^{O}}\]; Blood type A done clear
B) \[{{I}^{A}}{{I}^{B}}\]; Blood type AB done clear
C) \[{{I}^{B}}{{I}^{O}}\]; Blood type B done clear
D) \[{{I}^{O}}{{I}^{O}}\]; Blood type O done clear
question_answer 25) Codominance is depicted by
A) B blood group done clear
B) AB blood group done clear
C) O blood group done clear
D) A blood group done clear
The ABO blood grouping in human beings is an example for : |
(i) Dominance |
(ii) Incomplete dominance |
(iii) Co-dominance |
(iv) Multiple alleles |
A) (i) and (ii) only done clear
B) (ii), (iii) and (iv) done clear
C) (i) (ii) and (iv) done clear
D) (iii) and (iv) only done clear
question_answer 27) Which of the following genotypes does not produce an sugar polymer on the surface of the RBC ?
A) \[{{I}^{A}}{{I}^{A}}\] done clear
B) \[I{{i}^{B}}\] done clear
C) \[{{I}^{A}}{{I}^{B}}\] done clear
D) ii done clear
question_answer 28) Inheritance of flower colour is an example of incomplete dominance which is seen in :
A) Antirrhinum done clear
B) Pisum done clear
C) Solanum done clear
D) Hibiscus done clear
question_answer 29) Phenotypic ratio in plant Snapdragon in \[{{F}_{2}}\] is :
B) 2 : 1 done clear
C) 3 : 1 done clear
question_answer 30) Test cross is used to :
A) Check heterozygosity in \[{{F}_{1}}\] generation done clear
B) Check heterozygosity in \[{{F}_{2}}\] generation done clear
C) Check independent assortment in \[{{F}_{2}}\] generation done clear
D) Check segregation in \[{{F}_{2}}\] generation done clear
question_answer 31) The ultimate biological unit which controls heredity is called :
A) Genome done clear
B) Chromosome done clear
C) Genotype done clear
D) Gene done clear
question_answer 32) For making important contributions in respect of the nature of genes, the Nobel prize was awarded :
A) T.H. Morgan done clear
B) de Vries done clear
C) H.J. Muller done clear
D) Darwin done clear
question_answer 33) A pea plant parent having violet coloured flowers with unknown genotype was crossed with a plant having white coloured flowers, in the progeny 50% of the flowers were violet and 50% were white. The genotypic constitution of the parent having violet coloured flowers was:
A) Homozygous done clear
B) Merozygous done clear
C) Heterozygous done clear
D) Hemizygous done clear
Find out the correct option regarding the following cross? |
A) Monohybrid cross in pea plant done clear
B) Trihybrid cross in pea plant done clear
C) Out cross in pea plant done clear
D) Dihybrid cross in pea plant done clear
question_answer 35) ABO blood group is based on :
A) Co-dominance done clear
B) Incomplete dominance done clear
C) Epistasis done clear
D) Multiple allele done clear
question_answer 36) Test cross of dihybrid ratio is 1 : 1 : 1 : 1. It proves that :
A) \[{{F}_{1}}\] hybrid produces four different progenies done clear
B) \[{{F}_{2}}\] hybrid is homozygous done clear
C) Two different progenies are produced by \[{{P}_{1}}\] parents done clear
D) \[{{F}_{2}}\] hybrid is heterozygous done clear
question_answer 37) If \[{{F}_{1}}\] generation has all tall progenies and ratio of \[{{F}_{2}}\] generation is 3 : 1 (Tall : Dwarf), then it proves:
A) Law of independent assortment done clear
B) Law of segregation done clear
C) Law of dominance done clear
D) Incomplete dominance done clear
question_answer 38) How many pairs of contrasting characters in pea pod were chosen by Mendel :
A) 3 done clear
B) 5 done clear
C) 7 done clear
D) 9 done clear
question_answer 39) If a cross between two individual produce offsprings with 50% dominant character [A] and 50% recessive character [A] the genotype of parents are :
A) Aa AA done clear
B) Aa aa done clear
C) AA aa done clear
D) AA Aa done clear
question_answer 40) When yellow round heterozygous pea plants are self-fertilized, the frequency of occurrence of RrYY genotype among the offsprings is
A) 9/16 done clear
B) 3/16 done clear
C) 2/16 done clear
D) 1/16 done clear
question_answer 41) In an organism, tall phenotype is dominant over recessive dwarf phenotype, and the alleles are designate as T and t, respectively. Upon crossing two different individuals, total 250 offsprings were obtained. out of which 124 displayed tall phenotype and rest were dwarf. Thus, the genotype of the parents was
A) \[TT\times TT\] done clear
B) \[TT\times tt\] done clear
C) \[Tt\times Tt\] done clear
D) \[Tt\times tt\] done clear
question_answer 42) In a monohybrid cross between two heterozygous individuals, the number of pure homozygous individual? obtained in \[{{F}_{1}}\] generation is
A) 2 done clear
B) 4 done clear
C) 6 done clear
D) 8 done clear
question_answer 43) A woman with blood type 'O' has a child with blood type 'O'. If she claims a friend of hers with blood group 'A' as the father of the child, then the genotype of the father would be
A) \[{{I}^{O}}{{I}^{O}}\] done clear
B) \[{{I}^{A}}{{I}^{B}}\] done clear
C) \[{{I}^{A}}{{I}^{O}}\] done clear
D) \[{{I}^{A}}{{I}^{O}}\] done clear
question_answer 44) A woman with straight hair mates with a man with curly hair who is known to be heterozygous for that trait. What is the chance that their first child will have curly hair?
A) No chance done clear
B) One in two done clear
C) It is certain done clear
D) One in four done clear
question_answer 45) Which of the following crosses and resultant phenotype ratios are mismatched?
A) \[Tt\times Tt-3\,:\,1\] done clear
B) \[tt\times Tt-2\,;\,1\] done clear
C) \[Tt\,\,Yy\,\,\times \,\,ttyy\,\,-\,\,1\,\,:\,\,1\,\,:\,\,1\,\,:\,\,1\] done clear
D) \[Tt\,Yy\,\times \,\,TtYy\,\,\,-\,9\,\,:\,\,3\,\,:\,\,3\,\,:\,\,\,1\] done clear
question_answer 46) A man having the genotype EEFfGgHH can produce P number of genetically different sperms, and a woman of genotype IuLLMmNn can generate Q number of genetically different eggs. Determine the values of P and Q
A) P = 4, q = 4 done clear
B) P = 4, q = 6 done clear
C) P = 8, q = 4 done clear
D) P = 8, q = 8 done clear
question_answer 47) An organism, tall phenotype is dominant over recessive dwarf phenotype, and the alleles are designated as T and t, respectively. Upon crossing two different individuals, total 250 offsprings were obtained. out of which 124 displaced tall phenotype and rest were dwarf. Thus, the genotype of the parent; were
A) \[TT\,\,\,\times \,\,\,TT\] done clear
B) \[TT\,\,\,\times \,\,\,tt\] done clear
C) \[Tt\,\,\,\times \,\,\,Tt\] done clear
D) \[Tt\,\,\,\times \,\,\,tt\] done clear
question_answer 48) When yellow round heterozygous pea plants are self-fertilized, the frequency of occurrence of RrYY genotype, among the offsprings is
question_answer 49) ABO blood groups are determined by three different alleles. How many genotypes and phenotypes are possible?
Genotype | Phenotype |
3 | 1 |
Genotype | Phenotype |
6 | 4 |
Genotype | Phenotype |
4 | 6 |
Genotype | Phenotype |
9 | 7 |
question_answer 50) In a monohybrid cross between two heterozygous individuals, the number of pure homozygous individuals obtained in \[{{F}_{1}}\] generation is
question_answer 51) In Mendel's seven contrasting traits of pea total number of colours tested by him was
B) 3 done clear
C) 4 done clear
D) 5 done clear
question_answer 52) Which of the following statements is correct?
A) Each back cross is a test cross. done clear
B) Each test cross is a back cross. done clear
C) Crossing \[{{F}_{2}}\] with \[{{F}_{1}}\] is a test cross. done clear
D) Crossing \[{{F}_{2}}\] with \[{{P}_{1}}\] is called a test cross. done clear
question_answer 53) If a heterozygous tall plant is crossed with a homozygous dwarf plant, the proportion of dwarf progeny will be
A) 25% done clear
B) 50% done clear
C) 75% done clear
D) 100% done clear
question_answer 54) An allele is
A) Another word for gene done clear
B) A homozygous genotype done clear
C) A heterozygous genotype done clear
D) One of the several possible forms of gene done clear
question_answer 55) The graphical representation to calculate the probability of all possible genotypes of offsprings in a genetic cross was developed by
A) Gregor Mendel done clear
B) Kornberg done clear
C) Har Gobind Khorana done clear
D) Reginald C. Punnett done clear
question_answer 56) Choose the wrong statement from the following.
A) Failure of segregation of chromatids during cell division results in aneuploidy done clear
B) Additional copy of 'X' chromosome in males results in Klinefelter's syndrome done clear
C) Closely located genes in a chromosome always assort independently resulting in recombinants done clear
D) According to Mendel, recessive character never blends in heterozygous condition done clear
question_answer 57) In garden pea, round shape of seeds is dominant over wrinkled shape. A pea plant heterozygous for round shape of seed is selfed and 1600 seeds produced during the cross are subsequently germinated. How many seedings would have the parental phenotype?
A) 400 done clear
B) 1600 done clear
C) 1200 done clear
D) 800 done clear
question_answer 58) In a plant species, flower colour yellow is dominant over white, and fruit shape round is dominant over elongated. Crossing was performed between two pure lines - one having yellow-flower and round fruit, and another with white-flower and elongated-fruit. About 20 plants survived in \[{{F}_{1}}\] progeny. Plants of \[{{F}_{1}}\] were allowed to self fertilize, and about 960 plants survived in \[{{F}_{2}}\]. If the traits follow Mendelian inheritance, the number of plants would have yellow flower and round fruit in \[{{F}_{1}}\] and \[{{F}_{2}}\] are respectively
A) 20, 960 done clear
B) 20, 540 done clear
C) 10, 180 done clear
D) 10, 60 done clear
question_answer 59) Two plants one with black flower and other with white coloured flower were crossed in an experiment. In the next generation grey coloured flowers were obtained. The reason for the result is
A) incomplete dominance done clear
B) pseudodominance done clear
C) codominance done clear
D) None of these done clear
question_answer 60) Genes which code for a pair of contrasting characters are called
A) factors done clear
B) traits done clear
C) alleles done clear
D) gametes done clear
question_answer 61) First husband of Asha had ABO blood type A and their child had type O. She remarried and her second husband had ABO blood type B and their child had type AB. What is the ABO genotype of Asha and also name her blood type?
A) ii; Blood type O done clear
B) \[{{I}^{B}}\,\,i\] ; Blood type B done clear
C) \[{{I}^{A}}{{I}^{B}}\]; Blood type AB done clear
D) \[{{I}^{A}}\,\,i\] ; Blood type A done clear
question_answer 62) During incomplete dominance, \[{{F}_{2}}\] generation will have
A) 3 : 1 genotypic ratio done clear
B) 3 : 1 phenotypic ratio done clear
C) 1 : 2 : 1 genotypic ratio done clear
D) 2 : 2 : 1 phenotypic ratio done clear
question_answer 63) Which of the following cross will give recessive progeny in \[{{F}_{1}}\] generation?
A) \[TT\,\,\,\,\times \,\,\,\,\,tt\] done clear
B) \[Tt\,\,\,\,\,\times \,\,\,\,TT\] done clear
C) \[tt\,\,\,\,\,\times \,\,\,\,\,tt\] done clear
D) \[TT\,\,\,\,\,\times \,\,\,\,\,\,TT\] done clear
question_answer 64) In a dihybrid cross between two heterozygotes \[AaBb\,\,\times \,\,Aa\,\,Bb\], if we get 3 : 1 ratio among the offsprings, the reason for this may be
A) polygenes done clear
B) linked genes done clear
C) pleiotropic genes done clear
D) hypostatic genes done clear
question_answer 65) What result Mendel would have got, had he self-pollinated a tall \[{{F}_{2}}\] plant?
A) TT and Tt done clear
B) All Tt done clear
C) All TT done clear
D) All tt done clear
question_answer 66) Test cross is a cross between
A) Hybrid \[\times \] dominant parent done clear
B) Hybrid \[\times \] recessive parent done clear
C) Hybrid \[\times \] hybrid parent done clear
D) Two distantly related species done clear
question_answer 67) Colchicine interferes with
A) Chromosome replication done clear
B) Organisation of spindle done clear
C) Chromosome condensation done clear
D) Incorporation of nitrogen base done clear
question_answer 68) Webbed neck is a characteristic of
A) XXY done clear
B) XY done clear
C) XXY done clear
D) XO done clear
question_answer 69) Daughter of a colour-blind father and normal mother marries a colour-blind person. Colour-blindness in the family shall be
A) 50% sons and 50% daughters done clear
B) All sons and daughters done clear
C) All daughters done clear
D) All sons done clear
What are depicted in the following figure of chromosome? |
A) Dependent assortment of chromosomes done clear
B) Independent assortment of Chromatin done clear
C) Independent assortment of chromosomes done clear
D) Dependent assortment of Chromatin done clear
question_answer 71) Which one of the following statements is correct?
A) Down's syndrome occurs mostly in the children of very young mothers done clear
B) A person suffering from Down's syndrome has 47 chromosomes done clear
C) Down's syndrome is very common and occurs once is every 50 births done clear
D) Down's syndrome is caused when a sperm with an extra X chromosome fuses with a normal egg done clear
question_answer 72) Recessive characters are expressed when present:
A) Only when they are present on X chromosome of male done clear
B) Only when they are present on X chromosomes of female done clear
C) On any of autosome done clear
D) On any one chromosome done clear
question_answer 73) "Hypertrichosis" hairy ears are a sex-linked character associated with the
A) X chromosome done clear
B) XX chromosome done clear
C) XY chromosome done clear
D) Y chromosome done clear
question_answer 74) If this type of chromosome combination is found in man, we call this the "Klinefelter's syndrome"
A) One "X" chromosome and two "Y" chromosomes (XYY) done clear
B) Three "X" chromosomes (XXX) done clear
C) Three "Y" chromosomes (YYY) done clear
D) Two "X" chromosomes and one "Y" chromosome (XXY) done clear
question_answer 75) Mongoloid syndrome or Mongolian Idiocy is due to
A) 21 pairs normal, 22 and 23 extra chromosomes done clear
B) 22 pairs are normal, one chromosome has trisomy done clear
C) 24 pairs normal and one extra chromosome done clear
D) 22 pairs of normal chromosomes with one X chromosome done clear
question_answer 76) The exchange of generic material between chromatids of paired homologous chromosomes during first meiotic division is called
A) Transformation done clear
B) Chiasmata done clear
C) Crossing over done clear
D) Synapsis done clear
question_answer 77) Sex factor in bacteria
A) Chromosomal replicon done clear
B) F-Factor done clear
C) RNA - Fimbrae done clear
D) Sex-pilus done clear
question_answer 78) A person with 47 chromosomes due to an additional Y chromosome suffers from a condition called
A) Down's syndrome done clear
B) Super male done clear
C) Turner's syndrome done clear
D) Klinefelter's syndrome done clear
question_answer 79) For evolutionary success, a mutation must occur in
A) Germplasm DNA done clear
B) Somatic RNA done clear
C) Germplasm RNA done clear
D) Somatic DNA done clear
question_answer 80) Sometimes chromosome number increase or decrease due to:
A) Non-disjunction of chromosome done clear
B) Genetic repetition done clear
C) Mutation done clear
D) All of these done clear
The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes. Draw your conclusion on the basis of the pedigree. |
A) Allosome linked and recessive in nature done clear
B) Autosome linked and dominent in nature done clear
C) Allosome linked and dominent in nature done clear
D) Autosome linked and recessive in nature done clear
question_answer 82) Mutations are mainly responsible for controlling :
A) Increasing population rate done clear
B) Maintaining genetic continuity done clear
C) Variation in organisms done clear
D) Extinction of organisms done clear
question_answer 83) A woman with two genes, one for haemophilia and a gene for colour blindness on one of the 'X' chromosomes marries a normal man. Progeny will be :
A) All sons and daughters haemophilic and colour-blind done clear
B) Haemophilic and colour-blind daughters done clear
C) 50% haemophilic colour-blind sons and 50% normal sons done clear
D) 50% haemophilic daughters and 50% colour-blind daughters done clear
question_answer 84) In Down's syndrome, karyotyping has shown that the disorder is associated with trisomy of chromosome number 21 usually due to
A) Addition of extra chromosome during mitosis of the zygote done clear
B) Non-disjunction during egg-cell formation done clear
C) Non-disjunction during sperm-cell formation done clear
D) Non-disjunction during formation of egg cells and sperm-cells done clear
question_answer 85) Mental retardation in man associated with sex chromosomal abnormality is usually due to :
A) Reduction in X complement done clear
B) Increase in X complement done clear
C) Moderate increase in Y complement done clear
D) Large increase in Y complement done clear
question_answer 86) Albinism is known to be due to an autosomal recessive mutation. The first child of a couple with normal skin pigmentation was an albino. What is the probability that their second child will also be an albino?
question_answer 87) One of the chief factors responsible for clotting of blood is present on :
A) X Chromosome of male only done clear
B) X Chromosome of female only done clear
C) X Chromosome of both male and female done clear
D) Autosomes only done clear
What is shown in the following figure of pedigrees? |
A) Autosomal recessive trait like myotonic dystrophy done clear
B) Allosomal dominant trait like myotonic dystrophy done clear
C) Autosomal dominant trait like myotonic dystrophy done clear
D) Autosomal dominant trait like sickle - cell anaemia done clear
question_answer 89) A colour-blind daughter is born when :
A) Father is colour-blind, mother is normal done clear
B) Mother is colour-blind, father is normal done clear
C) Mother is carrier, father is normal done clear
D) Mother is carrier, father is colour-blind done clear
question_answer 90) In Down's syndrome (Mongolism) each cell has how many chromosomes:
A) 21st pair having one less done clear
B) 23rd pair with one less done clear
C) 45 chromosomes done clear
D) 47 chromosomes done clear
question_answer 91) Where are Barr bodies found?
A) Sperms of a man done clear
B) Ova of a woman done clear
C) Body cells (somatic) of man done clear
D) Body cells (somatic) of woman done clear
question_answer 92) The hereditary material present in the bacterium Escherichia coli is :
A) Single stranded DNA done clear
B) Single stranded RNA done clear
C) Double stranded DNA done clear
D) Double stranded RNA done clear
question_answer 93) Extranuclear genes occur in which of the following:
A) Mitochondria and cytoplasm done clear
B) Ribosomes and cytoplasm done clear
C) ER and cytoplasm done clear
D) Cytoplasm and Lysosomes done clear
question_answer 94) Mutations generally occur in which of the following genes:
A) Dominant genes done clear
B) Recessive genes done clear
C) Lethal genes done clear
D) Mendel's genes done clear
question_answer 95) Significance of the telomere is that it :
A) Seals the chromosome done clear
B) Stretches the spindle fibres done clear
C) Synthesises proteins done clear
question_answer 96) Plasmids are useful in genetic engineering because they :
A) Replicate independently done clear
B) Carry useful genes done clear
C) Are common in eukaryotes done clear
D) Can be extracted from viruses done clear
question_answer 97) Strength of linkage is inversely proportional to distance between the :
A) Chromomeres done clear
B) Genes done clear
C) Telomeres done clear
D) Chromatids done clear
question_answer 98) If a group of genes are getting deleted and undergoing some change it is due to :
A) Gene mutation done clear
B) Aneuploidy done clear
C) Chromosomal mutation done clear
D) Gene modification done clear
question_answer 99) XX male and XY female are very rare in humans. They are due to :
A) Genes of Y-chromosome are on X chromosome done clear
B) Crossing over between X and Y done clear
C) Non-disjunction of chromosomes done clear
D) All of the above done clear
question_answer 100) Which of the following occurs more than one and less than five in chromosome?
A) Chromomere done clear
B) Chromatid done clear
C) Centromere done clear
D) Secondary constriction done clear
question_answer 101) Change in sequence of nucleotide in DNA plant is:
A) Mutation done clear
B) Isolation done clear
C) Polyploidy done clear
D) Sexual reproduction done clear
question_answer 102) The segment of DNA which participates in crossing over is known as :
A) Muton done clear
B) Cistron done clear
C) Recon done clear
D) Replicon done clear
question_answer 103) Trisomy is :
A) One chromosome less than 2n. done clear
B) One chromosome more than 2n done clear
C) A hybrid obtained by crossing diploid and tetraploid done clear
D) Three chromosomes more than 2n done clear
question_answer 104) Kappa particles in Paramecium are indicating:
A) Nuclear inheritance done clear
B) Cytoplasmic inheritance done clear
C) Nucleo-cytoplasmic inheritance done clear
D) Mutation done clear
question_answer 105) Major role of colchicine in the eukaryotic cell is in :
A) Reducing number of chiasmata done clear
B) Causing endoduplication done clear
C) Dividing the nucleus done clear
D) Formation of polytene chromosome done clear
question_answer 106) The genes present exclusively on the X-chromosome in humans is concerned with :
A) Baldness and trichosis done clear
B) Night-blindness done clear
C) Facial hair and moustaches in males done clear
D) Red-green colour blindness done clear
question_answer 107) Down's syndrome is caused by an extra copy of chromosome number 21. What percentage of offsprings produced by an affected mother and normal father would be affected by this disorder?
A) 75% done clear
C) 25% done clear
question_answer 108) Linkage map of X-chromosome of fruit fly has 66 units, with yellow body gene (y) at one end and bobbed hair [b] gene at the other end. The recombination frequency between these two genes (y and b) should be :
A) > 75% done clear
B) < 50% done clear
C) 100% done clear
D) 66% done clear
question_answer 109) Genetic map of a eukaryotic cell is one that :
A) Shows the stages during cell division done clear
B) Establishes various stages in gene evolution done clear
C) Establishes sites of genes on a chromosome done clear
D) Shows the distribution of various species in a region done clear
question_answer 110) Genes for cytoplasmic male sterility in plants are generally located in :
A) Cytosol done clear
B) Nuclear genome done clear
C) Chloroplast genome done clear
D) Mitochondrial genome done clear
question_answer 111) When a diploid female plant (2n) is crossed with a tetraploid male plant (4n), then ploidy of endosperm cells in the resulting seed is :
A) Triploidy done clear
B) Diploidy done clear
C) Pentaploidy done clear
D) Tetraploidy done clear
question_answer 112) After the mutation at a genetic locus, the character of an organism changes due to change in :
A) DNA replication done clear
B) Protein structure done clear
C) RNA transcription pattern done clear
D) Protein synthesis pattern done clear
question_answer 113) One of the parents of a cross has a mutation in its mitochondria segregation of F2 progenies, mutaticz is found in :
A) All the progenies done clear
C) One-third of the progenies done clear
D) Fifty percent of progenies done clear
question_answer 114) Lack of independent assortment of genes A and B in fruit fly Drosophila is due to :
A) Repulsion done clear
B) Linkage done clear
D) Recombination done clear
Given below is the representation of a kind of chromosomal mutation. What is kind of mutation represented |
A) Deletion done clear
B) Duplication done clear
C) Inversion done clear
D) Translocation done clear
question_answer 116) Haemophilia is more commonly seen in human males than in human females because :
A) A greater proportion of girls die in infancy done clear
B) This disease is due to an Y linked recessive mutation done clear
C) This disease is due to an X linked recessive mutant done clear
D) This disease is due to an X linked dominant mutation done clear
question_answer 117) In Drosophila, gene for white eye mutation is also responsible for depigmentation of body parts. Thus gene that controls several phenotypes is called :
A) Oncogene done clear
B) Epistatic gene done clear
C) Hypostatic gene done clear
D) Pleiotropic gene done clear
question_answer 118) Phenylketonuria is the genetic disorder of :
A) Trisomic condition done clear
B) Monosomic condition done clear
C) Autosomal dominant gene done clear
D) Autosomal recessive gene done clear
question_answer 119) Haemophilia is a condition, where there is :
A) No production of haemoglobin in the blood done clear
B) No production of melanin in the skin done clear
C) A failure of clotting mechanism of blood done clear
D) A delay in clotting of blood done clear
question_answer 120) When the chromosome number of a given organism has one additional chromosome in one of the homologous pairs, the condition is known as
A) Trisomy done clear
B) Monosomy done clear
D) Nullisomy done clear
question_answer 121) In a skip generation inheritance of colour-blindness trait from a colour-blind man is passed on to :
A) Daughter done clear
B) Son done clear
C) Grand daughter done clear
D) Grand son done clear
question_answer 122) A medico-legal case of accidental interchange between two babies in a hospital, the baby of the blood group 'A' could not be rightly given to couple with :
A) Husband of 'O' group and wife of 'AB' group done clear
B) Husband of 'A' group and wife of 'B' group done clear
C) Husband of 'B' group and wife of 'O' group done clear
D) Husband of 'AB' group and wife of 'A' group done clear
question_answer 123) Genes present is cytoplasm of eukaryotic cells are found in :
A) Mitochondria and inherited via egg cytoplasm done clear
B) Lysosomes and peroxisomes done clear
C) Golgi bodies and smooth endoplasmic reticulum done clear
D) Plastids and inherited via male gamete done clear
question_answer 124) Action of ultraviolet rays on DNA is :
A) Induction of thymidine done clear
B) Deletion of base pair done clear
C) Addition of base pair done clear
D) Methylation of base pair done clear
question_answer 125) In Klinefelter's syndrome, the sex chromosome complement is :
A) 22A + XXY done clear
B) 22 A + XO done clear
C) 22 A + XY done clear
D) 22 A + XX done clear
question_answer 126) The recessive genes located on X-chromosome in humans are always :
A) Lethal in male and female done clear
B) Sub-lethal in male and female done clear
C) Expressed in males done clear
D) Expressed in females done clear
question_answer 127) After a mutation at a genetic locus, the character of an organism changes due to the change in :
A) Protein structure done clear
B) DNA replication done clear
C) Enzyme pattern done clear
D) RNA transcription pattern done clear
question_answer 128) A man and a woman, who do not show any apparent signs of certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance, do you suggest for the disease?
A) Autosomal dominant done clear
B) Sex-linked dominant done clear
C) Sex-limited recessive done clear
D) Sex-linked recessive done clear
question_answer 129) A woman with normal vision, but whose father was colour-blind, marries a colour-blind man. Suppose that the fourth child of this couple was a boy. This boy :
A) Must have normal colour vision done clear
B) Will be partially colour-blind since he is heterozygous for the colour-blind mutant allele done clear
C) Must be colour-blind done clear
D) May be colour-blind or may be of normal vision done clear
question_answer 130) Haemophilia is more commonly seen in human males than in human females because :
A) This disease is due to an X-linked dominant mutation done clear
B) A greater proportion of girls die in infancy done clear
C) This disease is due to X-linked recessive mutation done clear
D) This disease is due to Y-linked recessive mutation done clear
question_answer 131) A woman with 47 chromosomes due to three copies of chromosome 21 is characterized by:
A) Down syndrome done clear
B) Triploidy done clear
C) Turner syndrome done clear
D) Super femaleness done clear
question_answer 132) Barr body of a mammal represents :
A) All heterochromatin in female cells done clear
B) All heterochromatin in male and female cells done clear
C) The Y chromosome in the somatic cells of male done clear
D) One of the two X-chromosomes in somatic cells of female done clear
question_answer 133) Genetic counsellors can identify heterozygous individuals by :
A) Height of an individuals done clear
B) Colour of an individuals done clear
C) Screening procedures done clear
D) Weight of an individual done clear
question_answer 134) A marriage between normal visioned man and colour-blind woman will produce, which of the following type of offspring?
A) Normal sons and carrier daughters done clear
B) Colour-blind sons and carrier daughters done clear
C) Colour-blind sons and 50% carrier daughters done clear
D) 50% colour-blind sons and 50% carrier daughters done clear
question_answer 135) Linkage group in Escherichia coli is/are :
A) 4 done clear
C) 1 done clear
question_answer 136) Down's syndrome is caused by an extra copy of chromosome number 21. What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder?
A) 50% done clear
question_answer 137) Grain colour in wheat is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) \[\times \] aabbcc (light colour), in \[{{F}_{2}}\] generation what proportion of the progeny is likely to resemble either parent?
A) Half done clear
B) Less than 5 percent done clear
C) One third done clear
question_answer 138) Complete linkage is observed in :
A) Male Drosophila sp. done clear
B) Female Drosophila sp. done clear
C) Female silkworm done clear
D) Female rhesus monkey done clear
question_answer 139) Mutations that arise suddenly in nature are called :
A) Chromosomal mutations done clear
B) Induced mutations done clear
C) Gene mutations done clear
D) Spontaneous mutations done clear
question_answer 140) Occurrence of cell containing multiples of 2n genomes in diploid organisms is known as :
A) Aneuploidy done clear
B) Alloploidy done clear
C) Amphiploidy done clear
D) Endopolyploidy done clear
question_answer 141) Skin colour in man is determined by three pairs of polygenes. Following the cross AABBCC (dark colour) \[\times \] aabbcc (light colour), in \[{{F}_{2}}\] generation what proportion of the progeny is likely to resemble either parent?
B) 3% done clear
question_answer 142) Which of the following pair of features is a good example of polygenic inheritance?
A) Human height and skin colour done clear
B) ABO blood group in humans and flower colour of Mirabilis jalapa done clear
C) Hair pigment of mouse and tongue rolling in humans done clear
D) Human eye colour and sickle cell anaemia done clear
question_answer 143) The gene which controls many characters is called :
A) Codominant gene done clear
B) Polygene done clear
C) Pleiotropic gene done clear
D) Multiple gene done clear
question_answer 144) Sickle cell anaemia is :
A) Autosomal dominant inheritance done clear
B) X-linked recessive inheritance done clear
C) Autosomal recessive inheritance done clear
D) X-linked dominant inheritance done clear
question_answer 145) Polyploidy can be produced artificially by :
A) Colchicine done clear
B) Inbreeding done clear
C) Line breeding done clear
D) Self-pollination done clear
question_answer 146) Karyotype is :
A) Chromosome complement which is specific for each species of living organism done clear
B) All organisms possessing same type of chromosomes done clear
C) Division of nucleus done clear
D) One of the above done clear
question_answer 147) Identify the wrong statements:
A) In male grasshoppers 50 % of the sperms have no sex chromosome done clear
B) Usually female birds produce two types of gametes based on sex chromosomes done clear
C) The human males have one of their sex chromosomes much shorter than the other done clear
D) In domesticated fowls the sex of the progeny depends on the type of sperm that fertilizes the egg done clear
question_answer 148) Gynaecomastia is a common feature seen in:
B) Turner's syndrome done clear
C) PKU done clear
question_answer 149) The graphical representation to calculate the probability of all possible genotypes of offspring in a genetic cross is called :
A) Pedigree analysis done clear
B) Karyotype done clear
C) Punnett square done clear
D) Chromosome map done clear
question_answer 150) Chromosome is made up of :
A) DNA + pectin done clear
B) RNA + DNA done clear
C) DNA + histone done clear
D) Only histone done clear
What is shown in the following figure of human pedigrees? |
A) Autosomal dominant trait like Sickle - cell anaemia done clear
B) Allosomal recessive trait like Sickle - cell anaemia done clear
C) Autosomal recessive trait like colour blindness done clear
D) Autosomal recessive trait like Sickle - cell anaemia done clear
question_answer 152) In honeybee haploid stage develop into
A) Male caste done clear
B) Female caste done clear
C) Neutral caste done clear
question_answer 153) The number of linkage group(s) present in man is :
A) One done clear
B) Two done clear
C) Twenty-three done clear
D) Seven done clear
question_answer 154) The major cause of evolution of genes and protein is :
A) Point mutation done clear
B) Chromosomal aberration done clear
C) Sexual reproduction done clear
D) Gene duplication and divergence done clear
question_answer 155) Due to nondisjunction of chromosomes during spermatogenesis, sperms carry both sex chromosomes (22A + XY) and some sperms do not carry any sex chromosome (22A + X). If these sperms fertilize normal eggs (22A + X), what types of genetic disorders appear among the offsprings?
A) Turner's syndrome and Klinefelter's syndrome done clear
B) Down's syndrome and Klinefelter's syndroos done clear
C) Down's syndrome and Turner's syndrome done clear
D) Down's syndrome and cri-du-chat syndrora done clear
question_answer 156) Which genetic disorder is caused due to the presence of an additional copy of X-chromosome (A Karyotype of 44, XXY)?
A) Klinefelter's syndrome done clear
B) Down's syndrome done clear
D) Edward's syndrome done clear
question_answer 157) Multiple phenotype is seen in:
A) dominance relationship done clear
B) paniculate inheritance done clear
C) monogenic inheritance done clear
D) polygenic inheritance done clear
question_answer 158) Cystic Fibrosis disease in human being is due to
A) chromosome 5 done clear
B) chromosome 6 done clear
C) chromosome 7 done clear
D) chromosome 8 done clear
question_answer 159) In XO type of sex determination
A) females produce two different types of gametes done clear
B) males produce two different types of gametes done clear
C) females produce gametes with Y chromosomes done clear
D) males produce single type of gametes done clear
question_answer 160) Who used the frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes and mapped their position on the chromosome?
B) Correns done clear
C) Tschermark done clear
D) Alfred Sturtevant done clear
question_answer 161) Sickle cell anaemia is caused by the substitution of
A) valine by glutamic acid at sixth position of alpha chain of haemoglobin. done clear
B) valine by glutamic acid at sixth position of beta chain of haemoglobin. done clear
C) glutamic acid by valine at sixth position of alpha chain of haemoglobin. done clear
D) glutamic acid by valine at sixth position of beta chain of haemoglobin done clear
question_answer 162) Which following pair of diseases is caused by two genes located on human X-Chromosome?
A) Colour blindness and phenylketonuria. done clear
B) Colour blindness and haemophilia. done clear
C) Colour blindness and albinism. done clear
D) Colour blindness and hypertrichosis. done clear
question_answer 163) XX-XO type sex determination is recorded in
A) Grasshopper done clear
B) Drosophila done clear
C) Frog done clear
D) Earthworm done clear
question_answer 164) In XO types of sex determination
B) Males produce two different types of gametes done clear
question_answer 165) The behaviour of the chromosomes was parallel to the behaviour of genes during meiosis was noted by
A) Correns done clear
B) Tschermark done clear
C) Sutton and Boveri done clear
D) de Vries done clear
question_answer 166) Genes with multiple phenotypic effects are known as
A) hypostatic genes done clear
B) duplicate genes done clear
D) complementary genes done clear
question_answer 167) In case of incomplete linkage, the parental combinations obtained in \[{{F}_{2}}\], generation are
B) more than 50% done clear
D) less than 50% done clear
question_answer 168) Loss or gain of one more complete set of chromosomes along with the diploid complement is known as
A) aneuploidy done clear
B) euploidy done clear
C) reverse tandem duplication done clear
D) substitution done clear
question_answer 169) The traits which are expressed in only a particular sex through their genes occurs in the opposite sex too are known as
A) sex linked trait done clear
B) sex influence trait done clear
C) sex limited traits done clear
D) sex affected traits done clear
question_answer 170) Heterogamety is the term where an individual produces two types of gametes. The most appropriate answer is
A) Male Drosophila fly done clear
B) Female Drosophila fly done clear
C) Female bird done clear
D) Both [a] and [c] done clear
question_answer 171) In our society women are blamed for producing female children. Choose the correct answer for the sex-determination in humans.
A) Due to some defect like aspermia in man done clear
B) Due to the genetic make up of the particular sperm which fertilizes the egg done clear
C) Due to the genetic make up of the egg done clear
D) Due to some defect in the women. done clear
question_answer 172) Genetic variation in a population arises due to
A) recombination only done clear
B) mutation as well as recombination done clear
C) reproductive isolation and selection done clear
D) mutations only done clear
question_answer 173) Which one is the incorrect statement with regard to the importance of pedigree analysis?
A) It confirms that DNA is the carrier genetic information done clear
B) It helps to understand whether the trait in question is dominant or recessive. done clear
C) It confirms that the trait is linked to one of the autosomes. done clear
D) It helps to trace the inheritance of a specific trait. done clear
question_answer 174) A colour-blind man marries the daughter of another colour-blind man whose wife has a normal genotype for colour vision. In their progeny
A) all the children would be colour-blind done clear
B) all their sons are colour-blind done clear
C) none of the daughters would be colour-blind done clear
D) half of their sons and half of their daughters would be colour-blind. done clear
question_answer 175) Klinefelter's syndrome in human is an example of
A) Auto polyploidy done clear
B) Allopolyploidy done clear
C) Diploidy done clear
D) Aneuploidy done clear
question_answer 176) A person affected with phenylketonuria, lacks an enzyme that converts the amino acid phenylalanininto
A) valine done clear
B) proline done clear
C) histidine done clear
D) tyrosine done clear
question_answer 177) In sickle cell anemia, the sequence of amino acids from the first to the seventh position of the p-chain of haemoglobin S(HbS) is
A) His, Leu, Thr, Pro, Glu, Val, Val done clear
B) Val, His, Leu, Thr, Pro, Glu, Glu done clear
C) Thr, His, Pro, Val, Pro, Val, Glu done clear
D) Val, His, Leu, Thr, Pro, Val, Glu done clear
Statement-A: For a particular character in an individual, each gamete gets only one allele. |
Statement-B: Chromatids of a chromosome split (separate) and move towards opposite poles during anaphase of mitosis. |
A) Statement A is correct and statement B is wrong. done clear
B) Both the statements are correct and B is the reason for A. done clear
C) Statement B is correct and statement A is wrong. done clear
D) Both the statements are correct and B is not the reason for A. done clear
question_answer 179) Sickle cell anaemia is caused due to the substitution of
A) valine at the 6th position of beta globin chain by glutamine done clear
B) valine at the 6th position of alpha globin chain by glutamic acid done clear
C) glycine at the 6th position of alpha globin chain by glutamic acid done clear
D) glutamic acid at the 6th position of beta globin chain by valine done clear
question_answer 180) Anish is having colour blindness and married to Sheela, who is not colour-blind. What is the chance that their son will have the disease?
D) 0% done clear
question_answer 181) The frequency of crossing over occurring between two genes located on the same chromosome depends on
A) length of the chromosome done clear
B) position of the centromere done clear
C) activities of two genes done clear
D) distance between two genes done clear
question_answer 182) The enzyme involved in the crossing over between two homologous chromosomes is
A) nuclease done clear
B) RNA polymerase done clear
C) recombinase done clear
D) DNA polymerase done clear
question_answer 183) A couple, both carriers for the gene sickle cell anaemia planning to get married, wants to know the chances of having anaemic progeny?
B) 75% done clear
D) 25% done clear
question_answer 184) The total number of types of gametes produced in across between a negro and albino parent is
A) 64 done clear
B) 16 done clear
C) 08 done clear
D) 04 done clear
question_answer 185) Which of the following is correct match?
I | II | III | ||
Thalassemia | [A] | XO | (i) | Flat nose, simian crease |
I | II | III | ||
Down's syndrome | [B] | 42 AA + XY | (ii) | Webbing of neck |
I | II | III | I | ||
Turner's syndrome | [C] | 44 AA + XXX | (iii) | Anaemia, jaundice |
I | II | III | ||
Klinefelter's syndrome | [D] | 44 AA + XXY | (iv) | Tall, thin, eunuchoid |
question_answer 186) Sex determination by chromosomal difference in man and Drosophila is by mechanism called
A) XX-XY done clear
B) XX-XO done clear
C) ZZ-ZW done clear
D) Both [a] and [b] done clear
question_answer 187) Which of the following set of syndromes show 47 chromosomes in their genetic make up?
A) Down's syndrome, Patau's syndrome, Edward's syndrome done clear
B) Turner's syndrome, Edward's syndrome, Klinefelter's syndrome done clear
C) Klinefelter's syndrome. Turner's syndrome, Edward's syndrome done clear
D) All the above done clear
question_answer 188) In order to lessen the suffering of phenylketonurics their diet should have
A) no phenylalanine and no tyrosine done clear
B) low phenylalanine and normal requirement of tyrosine done clear
C) normal recommended amount of phenylalanine done clear
D) normal recommended amount of both phenylalanine and tyrosine done clear
question_answer 189) Drosophila flies with XXY genotype are females, but human beings with such genotype are abnormal males. It shows that :
A) Y-chromosome is essential for sex determination in Drosophila done clear
B) Y-chromosome in female determining in Drosophila done clear
C) Y-chromosome is male determining in human beings done clear
D) Y-chromosome has no role in sex determination either in Drosophila or in human beings done clear
Linkage groups : |
1. Have genes, which were linked together in a single chromosome |
2. Show independent assortment |
3. Do not show independent assortment |
4. In prokaryotes are more than one |
question_answer 191) Which of the following statements about colour blindness is correct?
A) 2% men are red colour blind, 6% are green colour blind done clear
B) 6% men are red colour blind, 2% are green colour blind done clear
C) 10% men are red colour blind, 5% are green colour blind done clear
D) 5% men are red colour blind, 10% are green colour blind done clear
question_answer 192) Choose the wrong statement.
A) In grasshoppers, besides autosomes males have only one X-chromosome, whereas females have a pair of X-chromosomes. done clear
B) In XY type of sex determination, both males and females have same number of chromosomes. done clear
C) In Drosophila, males have one X and one Y chromosome, whereas females have a pair of X- chromosomes besides autosomes done clear
D) In insects with XO type of sex determination, all sperms bear X-chromosome besides autosomes done clear
question_answer 193) Which one of the following is an example of poly genie inheritance?
A) Flower colour in Mirabilis jalapa done clear
B) Production of male honey bee done clear
C) Pod shape in garden pea done clear
D) Skin colour in humans done clear
question_answer 194) Identify a Mendelian disorder from the following :
C) Phenylketonuria done clear
D) Kline feller's syndrome done clear
question_answer 195) A man, whose father is colour blind, marries a lady who is daughter of a colour-blind man. Their off springs will be
A) all normal done clear
B) all colour blinds done clear
C) all sons colour blind done clear
D) some sons colour blind and some normal done clear
Related question.
OTP has been sent to your mobile number and is valid for one hour
Your mobile number is verified.
If you're seeing this message, it means we're having trouble loading external resources on our website.
If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.
To log in and use all the features of Khan Academy, please enable JavaScript in your browser.
Introduction to mendelian genetics.
looking to master the principles of inheritance and variation? Look no further! In this comprehensive article, we have compiled 100 questions with detailed answers, including multiple-choice questions (MCQs), to help you gain a thorough understanding of this important topic. From Mendelian inheritance to genetic mutations and DNA recombination, these questions cover a wide range of concepts and scenarios related to inheritance and variation.
Whether you're a student preparing for exams or a curious learner wanting to deepen your knowledge, this article is your one-stop resource. Each question is designed to challenge your understanding and test your knowledge of the principles at hand. With clear, concise answers provided, you can confidently check your comprehension and clarify any lingering doubts. By engaging with these questions, you'll develop a solid foundation in the principles of inheritance and variation. Ready to embark on this educational journey? Let's dive in and expand our understanding of the fascinating world of genetics.
The study of Principles of Inheritance and Variation is an integral part of Class 12 Biology, specifically covered in Chapter 4. This chapter delves into the complexities of how traits are passed down from one generation to another and explores the concept of genetic variation within populations. Students, particularly those gearing up for competitive exams like NEET, will find that focusing on Principles of Inheritance and Variation Class 12 important questions can help reinforce key concepts. These important questions are often framed around fundamental topics like Mendelian genetics, mutations, and chromosomal disorders.
When preparing for Class 12 board exams or NEET, a question bank can be highly beneficial. Various educational platforms and books offer Principles of Inheritance and Variation question bank, featuring a wide range of questions, including multiple-choice questions (MCQs). To make the most of your preparation time, consider downloading Principles of Inheritance and Variation MCQ PDF, which typically includes answers and explanations. These MCQs are not just pivotal for board exams but are also frequently seen in NEET, making them doubly valuable. You'll find that many Principles of Inheritance and Variation Class 12 MCQ NEET questions have also appeared as previous year questions (PYQ), offering a good understanding of the exam pattern.
For those looking for a focused revision strategy, Principles of Inheritance and Variation Class 12 notes for NEET can provide a quick yet comprehensive review of the chapter. These notes are designed to highlight the most important topics, often featuring case study questions and extra questions for further practice. If you're aiming to cover all bases, Principles of Inheritance and Variation worksheet can help solidify your understanding, featuring a range of questions from easy to complex. Moreover, these worksheets often come with answers, aiding in self-assessment.
Understanding the Principles of Inheritance and Variation is not just crucial for academic success but also offers real-world applications, such as in the fields of medicine and agriculture. Therefore, a thorough grasp of this chapter is essential. Whether you're working through Principles of Inheritance and Variation Class 12 NCERT questions or practicing from a dedicated MCQ PDF, the objective remains the same: mastering the key concepts to excel in both your board exams and competitive tests like NEET. And for that, tapping into a variety of resources, from notes PDF for board exams to important questions for NEET, can offer a well-rounded preparation strategy.
Mendelian Genetics refers to the set of principles formulated by Gregor Mendel based on his pea plant experiments. These principles provide a fundamental understanding of how traits are inherited. Mendel's work laid the foundation for the field of genetics, explaining how traits pass from parents to offspring through genes. Understanding Mendelian genetics is crucial for grasping more complex topics in genetics and offers foundational knowledge for future studies.
Mendel proposed three laws of inheritance based on his experiments: the Law of Segregation, the Law of Independent Assortment, and the Law of Dominance. These laws explain how individual traits are inherited independently and describe the dominant and recessive nature of genes. Grasping Mendel's laws is vital for comprehending more complex genetic interactions.
Monohybrid crosses involve one trait, whereas dihybrid crosses involve two traits. These types of crosses are essential for understanding how traits are inherited separately or together. Monohybrid crosses can illustrate the Law of Segregation, while dihybrid crosses can demonstrate the Law of Independent Assortment.
While Mendel's principles apply broadly, some exceptions do exist. Examples include incomplete dominance, where neither allele is dominant, and codominance, where both alleles are equally dominant. Understanding these exceptions allows students to appreciate the complexity of genetic inheritance.
Genes that are located close together on the same chromosome tend to be inherited together, known as genetic linkage. Crossing over during meiosis can, however, break this linkage, leading to new combinations of traits. This topic provides insights into the dynamics of gene combinations and inheritance patterns.
Chromosomal abnormalities can occur in the structure or number of chromosomes and often result in genetic disorders. Understanding these abnormalities is essential for grasping the complexities of human genetics and for the study of medicine.
Sex determination deals with how the sex of an individual is established, often through chromosomes like X and Y. Sex-linked inheritance involves genes located on these sex chromosomes, and understanding this is crucial for studying genetic disorders specific to one gender.
Genetic variation arises due to mutations, which are changes in the DNA sequence. Some mutations result in genetic disorders that can be inherited. Learning about mutations allows for a deeper understanding of genetic diversity and disease.
Modern genetics has expanded upon Mendel's work to include concepts like polygenic inheritance, where multiple genes affect a single trait. Epistasis involves the interaction between genes, and pleiotropy occurs when one gene influences multiple traits. These modern concepts provide a more complete understanding of the complexities of genetics.
Each of these topics adds a layer of understanding to the overarching subject of inheritance and variation, essential for Class 12 Biology and beyond.
Teaching resources, test generator, worksheet generator, elearning for students, practice question paper, mock test series, happy parenting, elearning for child, worksheet for child, mock test series for child, witknowlearn, privacy policy, terms and condition, refund/cancellation policy.
Or login with Google
Upgrade to better learning opportunities.
Table of Contents
Download the app to get CBSE Sample Papers 2023-24, NCERT Solutions (Revised), Most Important Questions, Previous Year Question Bank, Mock Tests, and Detailed Notes.
Class 12 Biology Principles of Inheritance and Variation Extra Questions. myCBSEguide has just released Chapter Wise Question Answers for class 12 Biology. There chapter wise Test papers with complete solutions are available for download in myCBSEguide website and mobile app. These Extra Questions with solution are prepared by our team of expert teachers who are teaching grade in CBSE schools for years. There are around 4-5 set of solved Biology Extra questions from each and every chapter. The students will not miss any concept in these Chapter wise question that are specially designed to tackle Board Exam. We have taken care of every single concept given in CBSE Class 12 Biology syllabus and questions are framed as per the latest marking scheme and blue print issued by CBSE for Class 12.
CBSE Class 12 Biology Ch – 5 Test Papers
Download as PDF
Ch-5 Principles of Inheritance and Variation
A homozygous tall pea plant with green seeds is crossed with a dwarf pea plant with yellow seeds.
Male | Female | ||
X | X | ||
X | X X | XX | |
Y | X Y | XY |
T | t | |
---|---|---|
TG | tg | |
Tg | tg |
TG | tg | Tg | tg | |
---|---|---|---|---|
TTGG | TtGG | TTGg | TtGg | |
TtGG | ttGG | TtGg | ttGg | |
TTGg | TtGg | TTgg | Ttgg | |
ttGg | Ttgg | Ttgg | ttgg |
Create question paper PDF and online tests with your own name & logo in minutes.
Question Bank, Mock Tests, Exam Papers, NCERT Solutions, Sample Papers, Notes
Save my name, email, and website in this browser for the next time I comment.
15 questions mcq test - case based questions test: principles of inheritance & variation - 2, direction: read the following text and answer the following questions on the basis of the same : sickle cell anaemia is a genetic disorder where the body produces an abnormal haemoglobin called haemoglobins. red blood cells are normally flexible and round, but when the haemoglobin is defective, blood cells take on a “sickle” or crescent shape. sickle cell anaemia is caused by mutations in a gene called hbb. it is an inherited blood disorder that occurs if both the maternal and paternal copies of the hbb gene are defective. in other words, if an individual receives just one copy of the defective hbb gene, either from mother or father, then the individual has no sickle cell anaemia but has what is called “sickle cell trait”. people with sickle cell trait usually do not have any symptoms or problems but they can pass the mutated gene onto their children. three inheritance scenarios can lead to a child having sickle cell anaemia : — both parents have sickle cell trait — one parent has sickle cell anaemia and the other has sickle cell trait — both parents have sickle cell anaemia the following statements are drawn as conclusions from the above data (kenya). i. patients with scd (sickle cell disease) are less likely to be infected with malaria. ii. patients with scd (sickle cell disease) are more likely to be infected with malaria. iii. over the years the percentage of people infected with malaria has been decreasing. iv. year 2000 saw the largest percentage difference between malaria patients with and without scd. choose from below the correct alternative..
If both parents have sickle cell trait, then there is a **25% chance** of the child having sickle cell anaemia.
Solution: When both parents have the sickle cell trait, they can pass on either a normal gene or the mutated gene to their child. The possible combinations are:
1. Normal gene from both parents (25% chance) 2. Mutated gene from one parent and normal gene from the other (50% chance - child becomes a carrier like the parents) 3. Mutated gene from both parents (25% chance - child has sickle cell anaemia)
So, there is a 25% probability that the child will inherit the mutated gene from both parents and, therefore, have sickle cell anaemia.
1 Crore+ students have signed up on EduRev. Have you? |
Direction: Read the following text and answer the following questions on the basis of the same :
Sickle cell anaemia is a genetic disorder where the body produces an abnormal haemoglobin called haemoglobins. Red blood cells are normally flexible and round, but when the haemoglobin is defective, blood cells take on a “sickle” or crescent shape. Sickle cell anaemia is caused by mutations in a gene called HBB.
It is an inherited blood disorder that occurs if both the maternal and paternal copies of the HBB gene are defective. In other words, if an individual receives just one copy of the defective HBB gene, either from mother or father, then the individual has no sickle cell anaemia but has what is called “sickle cell trait”. People with sickle cell trait usually do not have any symptoms or problems but they can pass the mutated gene onto their children. Three inheritance scenarios can lead to a child having sickle cell anaemia :
— Both parents have sickle cell trait
— One parent has sickle cell anaemia and the other has sickle cell trait
— Both parents have sickle cell anaemia
Sickle cell anaemia is a/an ________________ disease.
If both parents have sickle cell trait, then there is _______________of the child having sickle cell trait.
Read the following and answer the questions given below:
Turner’s syndrome is an example of monosomy. It is formed by the union of an allosome free egg and a normal ‘X’ containing sperm or a normal egg and an allosome free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, under developed breasts, small uterus, short stature, webbed neck and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormone to the women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
Assertion : Turners syndrome is caused due to absence of any one of the X and Y sex chromosome.
Reason : Individuals suffering from Turner 'syndrome show masculine as well as feminine development.
Turner’s syndrome is an example of
Which of the following statements regarding Turner’s syndrome is incorrect?
Number ot barr body present in a female with Turners syndrome is
Turner’s syndrome is a/an
Haemophilia is a sex linked disease which is also known as bleeder’s disease as the patient will continue to bleed even from a minor cut since he or she does not possess the natural phenomenon of blood clotting due to absence of anti-haemophilic globulin or factor VIII and plasma thromboplastin factor IX essential for it. As a result of continuous bleeding the patient may die of blood loss. Colour blindness is another type of sex linked trait in which the eye fails to distinguish red and green colours. Vision is however, not affected and the colour blind can, lead a normal life, reading, writing and driving (distinguishing traffic lights by their position).
Anup is having colourblindness and is married to Soni who is normal. What is the chance that their son will have the disease?
Colour blindness is a sex-linked recessive disorder, which results in defects in either red or green cone of an eye which ultimately leads to the failure in discriminating between red and green colour. The gene for colour blindness is located on X-chromosome.
If a colourblind man marries a normal women the chances for their son to be colourblind is 0% because son will receive X-chromosome from his mother (who is not colourblind) and Y from the father (as gene of colour blindness is present on X, so Y chromosome is not affected at all). Thus, there is no chance for their son to be affected. Infact their girl child (daughter) will be the carrier of the disease.
Haemophilia is a sex linked disease which is also known as bleeder’s disease as the patient will continue to bleed even from a minor cut since he or she does not possess the natural phenomenon of blood clotting due to absence of anti-haemophilic globulin or factor VIII and plasma thromboplastin factor IX essential for it. As a result of continuous bleeding the patient may die of blood loss. Colour blindness is another type of sex linked trait in which the eye fails to distinguish red and green colours. Vision is however, not affected and the colour blind can, lead a normal life, reading, writing and driving (distinguishing traffic lights by their position).
A man whose father was colourblind and mother was normal marries a woman whose father was haemophilic and mother was normal. Which of the following is true for their progenies? [Note: Percentage is from the total number of progenies.]
If a haemophilic man marries a woman whose father was haemophilic and mother was normal then which of the following holds true for their progenies?
Which of the following statements is incorrect regarding haemophilia?
Directions: In the following questions, a statement of assertion is followed by a statement of reason.
Assertion: In F 2 generation of plant Mirabilis jalapa, the pink coloured flowers appear.
Reason: This is observed due epistatic suppression of white colour alleles in one of parental flowers by red colour alleles.
Case based questions test: principles of inheritance & variation - 2 mcqs with answers, online tests for case based questions test: principles of inheritance & variation - 2.
cation olution |
Join the 10M+ students on EduRev |
Create your account for free.
IMAGES
VIDEO
COMMENTS
Free PDF Downloads of CBSE Class 12 Biology Chapter 5 Principles of Inheritance and Variation Case Study and Passage Based Questions with Answers were Prepared Based on the Latest Exam Pattern. Students can solve Class 12 Biology Case Study Questions Principles of Inheritance and Variation to know their preparation level.
By QB365 on 08 Sep, 2022 . QB365 provides a detailed and simple solution for every Possible Case Study Questions in Class 12 Biology Subject - Principles of Inheritance and Variation, CBSE.
QB365 Provides the updated CASE Study Questions for Class 12 Biology, and also provide the detail solution for each and every case study questions . Case study questions are latest updated question pattern from NCERT, QB365 will helps to get more marks in Exams
Case Study/Passage Based Questions: Question 1: Study the flowchart given below and answer the questions that follow. (i) What is a mutagen? Name a physical factor that can be mutagen.(ii) What is point mutation? Give one example.(iii) Mention two causes of frame-shift mutation. Answer Ans. (i) All the physical and chemical factors that induce mutation … Continue reading Case Study and ...
Download PDF of Class 12 Biology Case Study Questions Chapter 5 Principles of Inheritance and Variation. Practice CBSE Class 12 Biology Important Questions Chapter Wise, MCQ's, Extra Questions for Exams.
Explore important questions on Principles of Inheritance and Variations Class 12 Biology along with the answers for reference.
Case Study on Principles of Inheritance & Variation Class 12 Biology: Here, you will get Case Study Questions on Class 12 Principles of Inheritance & Variation PDF at free of cost. Along with you can also download Principles of Inheritance & Variation case study questions for Class 12 exercise wise
Class 12th Biology - Principles of Inheritance and Variation Case Study Questions and Answers 2022 - 2023 - Complete list of 12th Standard CBSE question papers, syllabus, exam tips, study material, previous year exam question papers, centum tips, formula, answer keys, solutions etc..
B I O LO G Y B Y SM R I T I P AN D E Y. B.Tech & M.Tech. 3. Read the following passage and answer the given questions: Mendelian disorders are mainly determined by alteration or mutation in the single gene.
We have given these Class 12 Biology Important Questions Chapter 5 Principles of Inheritance and Variation to solve different types of questions in the exam. Go through these Class 12 Biology Chapter 5 Important Questions, Principles of Inheritance and Variation Important Questions & Previous Year Questions to score good marks in the board examination. Class 12 […]
Here are some questions from the chapter: Principles of Inheritance and Variations; Class-XII, to check your understanding level. These questions pertains to the concepts of Mendelism and gene interactions only. Questions for the rest of the concepts will be available soon.
Explore how traits are inherited through Mendelian genetics. Also explore genetic disorders and pedigree analysis methods. This unit is aligned to the Class 12 NCERT curriculum.
Directions : (6 - 10) Read the passage given below and answer the following questions. Though the genotypic ratios can be calculated using mathematical probability, but simply looking at the phenotype of a dominant trait, it is not possible to know the genotypic composition.
Class 12 biology chapter 5 important questions PDF provides the students with well-explained answers to the most important and frequently asked questions of the chapter, such that each of the students can get a more easy way of learning and understanding the chapter. This in turn would help them ace their exams. Class 12 biology principles of inheritance and variation important questions are ...
Free PDF Downloads of CBSE Class 12 Biology Chapter 6 Molecular Basis of Inheritance Case Study and Passage Based Questions with Answers were Prepared Based on the Latest Exam Pattern. Students can solve Class 12 Biology Case Study Questions Molecular Basis of Inheritance to know their preparation level.
Principles of Inheritance and Variation Class 12 Important Questions: Here, we provide Biology Class 12 Important Questions for Principles of Inheritance and Variation with solutions PDF. Also you can download here Important Questions on Principles of Inheritance and Variation for Class 12 Biology to getting higher marks.
In a plant species, flower colour yellow is dominant over white, and fruit shape round is dominant over elongated. Crossing was performed between two pure lines - one having yellow-flower and round fruit, and another with white-flower and elongated-fruit.
Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.
looking to master the principles of inheritance and variation? Look no further! In this comprehensive article, we have compiled 100 questions with detailed answers, including multiple-choice questions (MCQs), to help you gain a thorough understanding of this important topic.
Answer. Selfing of F1, Explanation: In monohybrid and dihybrid cross F2 generation is obtained by selfing of Fi hybrids as male and female. Segment of DNA, Explanation: Genes are segment of DNA present on chromosome.Large numbers of genes are located on single chromosome. A gene or genes determines the traits of the individual.
Solutions of Case Based Questions Test: Principles of Inheritance & Variation - 1 questions in English are available as part of our course for NEET & Case Based Questions Test: Principles of Inheritance & Variation - 1 solutions in Hindi for NEET course. Download more important topics, notes, lectures and mock test series for NEET Exam by signing up for free.
Solutions of Case Based Questions Test: Principles of Inheritance & Variation - 2 questions in English are available as part of our course for NEET & Case Based Questions Test: Principles of Inheritance & Variation - 2 solutions in Hindi for NEET course. Download more important topics, notes, lectures and mock test series for NEET Exam by signing up for free.