Class 12 Principles of Inheritance and Variation MCQ with Answer

Class 12: Principles of Inheritance and Variation MCQs: Inheritance is the term given to the process by which characters are passed from parents to offspring which forms the basis of heredity. Heredity is the process of passing down genetic traits from parents to offspring. The degree of difference in characters between a parent and offspring is called variation. All these are studied under genetics which deals with the study of inheritance and variation of characters passed from parents to offspring. The first proper documented study of this inheritance and variation was done by G.J. Mendel which is why he is considered the father of genetics.

Class 12 Biology Principles of Inheritance and Variation MCQ with Answer

Q1. Which of the following statements is the most appropriate for sickle cell anaemia?

1. It cannot be treated with iron supplements.
2. It is a molecular disease.
3. It confers resistance to acquiring malaria.
4. All of the above.

Q2. From a cross AABb × aaBb, the genotypes AaBB : AaBb : Aabb will be obtained in the ratio:

1. 1 : 1 : 2
2. 1 : 2 : 1
3. 2 : 1 : 1
4. 2 : 1 : 2

Q3. If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male
progeny, the disease is:

1. Autosomal dominant.
2. Autosomal recessive.
3. Sex-linked dominant.
4. Sex-linked recessive.

Q4. If a haemophilic woman marries a normal man:

1. All their children will be normal.
2. All their sons will be haemophilic.
3. All their daughters will be haemophilic.
4. 50% sons and 50% daughters will be haemophilic.

Q5. A woman with normal vision has a colorblind father. She marries a colourblind man. What proportion of their
children will be colourblind?

1. 0%
2. 25%
3. 50%
4. 100%

Q6. Two genes ‘A’ and ‘B’ are linked. In a dihybrid cross involving these two genes, the F heterozygote is crossed with
homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation?

1. 1 : 1 : 1 : 1.
2. 9 : 3 : 3 : 1.
3. 3 : 1.
4. 1 : 1.

Q7. In the F₂ generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are:

1. Phenotypes – 4; genotypes – 16.
2. Phenotypes – 9; genotypes – 4.
3. Phenotypes – 4; genotypes – 8.
4. Phenotypes – 4; genotypes – 9.

Q8. The inheritance pattern of a gene over generations among humans is studied by the pedigree analysis. Character
studied in the pedigree analysis is equivalent to:

1. Quantitative trait.
2. Mendelian trait.
3. Polygenic trait.
4. Maternal trait.

Q9. A Across between two tall plants resulted in offspring having few dwarf plants. What would be the genotypes of
both the parents?

1. TT and Tt.
2. Tt and Tt.
3. TT and TT.
4. Tt and tt

Q10. In a certain taxon of insects some have 17 chromosomes and the others have 18 chromosomes. The 17 and 18
chromosome-bearing organisms are:

1. Males and females, respectively.
2. Females and males, respectively.
3. All males.
4. All females.

Q13. All genes located on the same chromosome:

1. Form different groups depending upon their relative distance.
2. Form one linkage group.
3. Will not from any linkage groups.
4. Form interactive groups that affect the phenotype.

Q14. ZZ/ ZW type of sex determination is seen in:

1. Platypus.
2. Snails.
3. Cockroach.
4. Peacock.

Q15. Mendel’s Law of independent assortment holds good for genes situated on the:

1. Non-homologous chromosomes.
2. Homologous chromosomes.
3. Extra nuclear genetic element.
4. Same chromosome.

Q16. Person having genotype I^A I^B would show the blood group as AB. This is because of:

1. Pleiotropy.
2. Co-dominance.
3. Segregation.
4. Incomplete dominance

Q17. In sickle cell anaemia glutamic acid is replaced by valine. Which one of the following triplets codes for valine?

1. G. G. G.
2. A. A. G.
3. G. A. A.
4. G. U. G.

Q18. Distance between the genes and percentage of recombination shows:

1. A direct relationship.
2. An inverse relationship.
3. A parallel relationship.
4. No relationship

Q19. Which of the following will not result in variations among siblings?

1. Independent assortment of genes.
2. Crossing over.
3. Linkage.
4. Mutation.

Q20. For question two statements are given-one labelled Assertion and the other labelled Reason. Select the correct
answer to these questions from the codes (a), (b), (c) and (d) as given below.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Codominant alleles lack dominant recessive relationship.
Reason: Codominant alleles show incomplete dominance.