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Principles of Inheritance and Variation MCQ Questions with Answers Class 12 Biology
Question- Mendel selected pea as material for his experiments because
(a) it is an annual plant with comparatively short life cycle.
(b) the flowers are self-pollinated.
(c) the number of seeds produced is quite large.
(d) all of the above.
Question- Which of the following crosses would produce a genotypic ratio of 1 : 2 : 1 in F2 ?
(a) AB × AB
(b) Ab × ab
(c) Ab × Ab
(d) ab × ab
Question- Sickel-cell anaemia is an example of
(a) sex-linked inheritance.
(b) deficiency disease.
(c) autosomal heritable disease.
(d) infectious disease.
Question- The crossing of F1 to homozygous recessive parent is called
(a) back cross
(b) test cross
(c) F1 cross
(d) all of these
Question- In humans, the dominance relationship between the A and B alleles of the ABO blood group gene is an example of
(a) complete dominance
(b) incomplete dominance
Question- Distance between the genes and percentage of recombination shows
(a) a direct relationship
(b) an inverse relationship
(c) a parallel relationship
(d) no relationship
Question- It is well known that Queen Victoria of England was a carrier for haemophilia. Since this is an X-linked disease, it can be predicted that
(a) all of her sons would have had disease.
(b) all her daugthers would have been carriers.
(c) her father must definitely have had haemophilia.
(d) haemophilia would have occurred in more of her male than her female descendents.
Question- Mutations can be induced with
(a) infrared radiations
(b) I AA
(d) gamma radiations
Question-The number of phenotypes in ABO blood groups is
Question- Sex is determined in human beings
(a) by ovum.
(b) at time of fertilization.
(c) 40 days after fertilization.
(d) seventh to eight week when genitals differentiate in foetus.
Question- Extra chromosome ‘X’ is present in which one of the following cases?
(a) Down syndrome
(b) Klinefelter syndrome
(c) Turner syndrome
(d) Bleeder’s disease
Question- The person with Turner’s syndrome has
(a) 45 autosomes and X sex chromosome
(b) 44 autosomes and XYY sex chromosomes
(c) 45 autosomes and XYY sex chromosomes
(d) 44 autosomes and X sex chromosome
Question- Punnett square is used to know the
(a) outcome of a cross
(b) probable result of a cross
(c) types of gametes
(d) result of meiosis
Question- A character which is expressed in a hybrid is called
Question- The ratio of phenotypes in F2 of a monohybrid cross is
(a) 3 : 1
(b) 1 : 2 : 1
(c) 9 : 3 : 3 : 1
(d) 2 : 1
Question- ABO blood group system is due to
(a) multifactor inheritance
(b) incomplete dominance
(c) multiple allelism
Question- A pure tall pea was crossed with a pure dwarf pea. All the plants of F1 were found to be tall. This is due to
(a) law of dominance.
(b) disappearance of factor for dwarfness in F1 generation.
(c) segregation of factors.
Question- Which Mendelian idea is depicted by a cross in which the F1 generation resembles both the parents?
(a) Law of dominance
(b) Inheritance of one gene
(d) Incomplete dominance
Question- Mendel’s last law is
(c) independent assortment
(d) polygenic inheritance
Question- Three children in a family have blood types O, AB and B respectively. What are the genotypes of their parents?
(a) IA i and IBi
(b) IAIB and i i
(c) IBIB and IAIA
(d) IAIA and IBi
1. Define heredity, genetics, and inheritance.
2. Why did Mendel select pea plant for his experiments?
3. How did Mendel make sure that the pea plants were true breeding?
4. List the traits in garden pea plant which Mendel studied in his breeding experiments.
5. What is emasculation technique?
6. Define the following terms:
(i) Allele (ii) homozygous
(iii) Heterozygous (iv) Dominant gene
(v) Recessive gene (vi) Genotype
7. (a) What is monohybrid cross? How did Mendel carry out this cross? Show with help of Punnet square.
(b) Explain Law of Dominance.
(c) Explain Law of Segregation of gametes.
8. What kind of gametes would be produced by the organisms having the following genotypes?
9. In human beings, blue eye colour is recessive to brown eye colour. A brown-eyed man has a blueeyed mother.
(a) What is the genotype of the man and his mother?
(b) What are the possible genotypes of his father?
(c) If a man marries a blue-eyed woman, what are the possible genotypes of their offspring?
10. What is test cross? Give its use.
11. In dogs black coat colour is dominant over white. What coloured dog will you choose to breed a given black dog to find its genotype? What is this type of cross known as?
12 (a) What is incomplete dominance? Describe one example of incomplete dominance.
(b) What is the difference between dominance and incomplete dominance?
13. What is multiple allelism? Give its suitable example.
14. What is codominance? Give suitable example.
15. How is codominance different from incomplete dominance?
16 (a) Describe briefly the dihydrid cross conducted by Mendel.
(b) State the Law of Independent Assortment.
17. State the reasons for which the published work for Mendel remained unrecognized for several years.
18. Who proposed the chromosome theory of inheritance? Give the salient features of this theory.
19. Why did Morgan select Drosophilia for his experiments?
20. What is linkage? Describe briefly the two types of linkage.
21. State the relationship between linkage and crossing over.
22. Briefly mention the contribution of T.H.Morgan in genetics.
23. What is the role of Henking in discovery of X-chromosome?
24. What are autosomes and sex chromosomes?
25. discuss briefly different types of sex determination
(a) XO-XX type (b) XX-XY type (c) ZW-ZZ type
26. What is male heterogamety and female heterogamety?
27. Define mutation and mutagens.
28. What is point mutation and chromosomal mutations?
29. What is pedigree analysis? What are the symbols used in such an analysis?
30. Give the use of pedigree analysis.
31. What is haemophilia? Why do generally only human males suffer from haemophilia? Can women also suffer? Explain
32. How is sickle cell anaemia caused? What are its symptoms?
33. Write short note on Phenylketouria.
34. What is aneuploidy? Differentiate between trisomic and haploid condition.
CBSE Class 12 Biology Principles Of Inheritance And Variation Worksheet Set A
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