BIOLOGY XII
CHAPTER-PRINCIPLES OF INHERITANCE AND VARIATION
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PART A
1. How many pairs of contrasting characters in pea plants were studied on color basis by Mendel in his experiments?
a) Seven

 b) Three 

c) Six

 d) Eight

2. Segregation of Mendelian factors (no linkage, no crossing over ) occurs during
a) Anaphase I 

b) Anaphase II 

c) Diplotene

 d) Metaphase I

3. Identify the wrong statements
a) In male grasshoppers 50% of the sperms have no sex chromosome
b) In domesticated fowls the sex of the progeny depends on the type of sperm that fertilizes the egg.
c) The human males have one of their sex chromosomes much shorter than the other
d) The male fruit fly is heterogametic

4. Which one of the following conditions correctly describes the manner of determining the sex?
a) Homozygous sex chromosomes (ZZ) determine female sex in birds
b) XO type of sex chromosomes determine male sex in grasshopper
c) XO condition in humans as found in turners syndrome, determines female sex

d) Homozygous sex chromosomes (XX) produce male in Drosophila

5. Genes with multiple phenotypic effects as are known as
a) Hypostatic genes

 b) duplicate genes
c) Pleiotropic genes 

d) Complementary genes

6. Which of the following is a symptom of Down’s syndrome?
a) Flat back of head

b) Many “loops” on finger tips

c) Big and wrinkled tongue 

d) All of these

7. A man with enlarged breasts, sparse body hair and XXY genotype is suffering from
a) Down’s syndrome

 b) Tuner’s syndrome
c) Klinefelter syndrome

 d) super male

8. Which of the following disorders are caused due to recessive autosomal mutations?
a) Tuner’s syndrome and sickle cell anemia
b) Edward’s syndrome and Down’s syndrome
c) Cystic fibrosis and phenylketonuria
d) Alzheimer’s disease and Huntington’s chorea

9. Select a female heterogametic animal from the following
a) Human beings 

b) Drosophila 

c) Grasshopper

 d) None of these

10. Select the odd one out.
a) Violet flower 

b) Round seed 

c) Yellow pod 

d) Tall stem

11. A pure tall pea plant is crossed with pure dwarf pea plant. The progeny is self-pollinated. Find out the ratio of true breeding tall pea plants to true breeding dwarf pea plants.
a) 2:1 

b) 1:1 

c) 3:1 

d) 1:2

12. In a plant, red fruit (R) is dominant over yellow fruit (r) and tallness (T) is dominant over shortness (t). If a plant with RRTt genotype is crossed with a plant that is rrtt
a) 25% will be tall with red fruit

 b) 75% will be tall with red fruit
c) 50% will be tall with red fruit 

d) all the offspring will be tall with red fruit

13. F2 generation in a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1:2:1. It represents in case of
a) Monohybrid cross with complete dominance
b) Monohybrid cross with incomplete dominance
c) Dihybrid Cross
d) Co – Dominance

14. Experimental verification of the chromosomal theory of inheritance was done by
a) Boveri

 b) Morgan

 c) Mendel 

d) Sutton

15. If a character is controlled by polygenic principle where there are three gene namely A, B and C which among the following groups of genotypes are able to produce the same phenotype
a) AABBCC, AaBbCc, aabbcc

 b) aaBBcc, AaBbcc, aabbCC
c) AAbbcc, aaBBCC, aaBbcc 

d) none of the above

16. Which of the following characteristics represent ‘Inheritance of blood groups’ in humans?
a. Dominance
b. Co-dominance
c. Multiple dominance
d. Incomplete dominance
e. Polygenic inheritance
a) b, c and e b) a, b and c c) b, d and e d) a, c and e

17. Thalassemia and sickle cell anemia are caused due to a problem in globin molecule synthesis. Select the correct statement
a) Both are due to a qualitative defect in globin chain synthesis
b) Both are due to a quantitative defect in globin chain synthesis
c) Thalassemia is due to less synthesis of globin molecules
d) Sickle cell anemia is due to a quantitative problem of globin molecules

18. If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is
a) 0.75 

b) 1 

c) 0 

d) 0.5

19. Match the terms in Column-I with their description in Column-II and choose the correct option
Column-I Column-II
(a) Dominance – (i) Many genes govern a single character
(b) Codominance – (ii) In a heterozygous organism only one allele expresses itself
(c) Pleiotropy – (iii) In a heterozygous organism both alleles express themselves fully
(d) Polygenic inheritance – (iv) A single gene influences many characters

a) (a) → (ii); (b) → (i); (c) → (iv); (d) → (iii)
b) (a) → (ii); (b) → (iii); (c) → (iv); (d) → (i)
c) (a) →(iv); (b) → (i); (c) → (ii); (d) → (iii)
d) (a) →(iv) ; (b) → (iii); (c) → (i); (d) → (ii)

20. A man with blood group ‘A’ marries a woman with blood group ‘B’. What are all the possible blood groups of their offspring?
a) O only 

b) A and B only
c) A, B and AB only

 d) A, B, AB and O

21. A human female with Turner’s syndrome
a) Exhibits male characters
b) is able to produce children with normal husband.
c) Has 45 chromosomes with XO
d) Has one additional X chromosome

22. Lethal genes are
a) Causative for appearance of ancestral traits
b) Always recessive
c) Genes present on different chromosomes but influencing single trait
d) Killer in homozygous state

23. The ratio of 9:3:3:1 is due to
a) Segregation of characters 

b) Independent assortment of genes
c) Crossing over of chromosomes 

d) Homologous pairing between chromosomes

24. The offspring of AAbb × aaBB is crossed with, aabb. The genotypic ratio of progeny will be
a) 9:3:3:1 

b) 1:2:1 

c) 1:1:1:1 

d) 4:1

25. Phenotypic and genotypic ratio in F generation in incomplete dominance is
a) 1:2:1 and 1:2:1 

b) 3:1 and 1:2:1
c) 9:6 and 3:1 

d) 9:3:3:1 and 1:2:1:4:1:1:2:1:2:1

26. Mary’s father has haemophilia but her husband is also haemophilic. What would be the chance other daughter having this disease?
a) 0% 

b) 50% 

c) 100%

 d) 25%

27. Which of the following statements regarding: crossing-over is incorrect?
a) Crossing-over disrupts the linkage between genes on the same chromosome.
b) Crossing-over disrupts the linkage between genes on different chromosomes.
c) Crossing-over produces new genetic combinations.
d) Crossing-over produces non-parental chromosomes

28. In genetics, the term test cross means:
a) The crossing of F1 individual with homozygous recessive.
b) Crossing an F1 individual with either of the two parents.
c) Crossing F1 individual with another F1 individual.
d) Crossing F1 individual with that of F2.

29. In Mendelian Dihybrid cross, when heterozygous round yellow are self-crossed, round green offspring’s are produced which are represented by genotype?
a) RrYy, RrYY, RRYy 

b) RrYY, RRyy, rryy
c) rrYy, rrYY 

d) RRyy, Rryy

30. A diseased man marries a normal woman. They have three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is:
a) Sex-linked dominant 

b) Sex-linked recessive
c) Sex-linked character 

d) Autosomal dominant

31. One chromosome of a homologous pair carries the genes J and K. The other chromosome of the pair carries the genes j and k at corresponding loci. Crossing over results in exchange of chromosome segments and production of gametes with new combinations of genes. A recombinant type gamete resulting from this crossover might contain:
a) Genes J and K 

b) Genes j and K
c) Genes J and j 

d) Genes j and k

32. Haemophilia is mentioned as a trait carried by the mother and passed to her sons. What is the pattern of inheritance for this trait?
a) Haemophilia is an allele carried on one of the mother’s autosomal chromosomes.
b) Haemophilia is an allele carried on the Y chromosome because more males have this genetic disorder than females.
c) Haemophilia is an allele carried on the X chromosome and can be directly inherited by the son from the father or the mother.
d) Haemophilia is carried on the X chromosome and can only be inherited by the son if the mother is a carrier.

33. Gynandromorphs are animals having:

a) Same sex in all cells of the body.
b) Different sexes in all cells of the body.
c) Same sex in different cells of the body.
d) Different sexes in different cells of the body.

34. Which of the following is an example for sex-influenced inheritance?

a) Baldness

 b) Haemophilia
c) Colour blindness

 d) Down’s syndrome

35. If a trait passes from father to all his daughters but none of his sons, the trait is:
a) Autosomal dominant 

b) Autosomal recessive
c) Sex linked dominant

 d) Sex linked recessive

PART B

36. Select the incorrect match
a) Submetacentric chromosomes – L-shaped chromosomes
b) Allosomes – Sex chromosomes
c) Lamp brush chromosomes – Diplotene bivalents
d) Polytene chromosomes – Oocytes of amphibians

37. Trisomy of 21st chromosome results in
a) Down’s syndrome 

b) Sickle cell anemia
c) Turner’s syndrome

 d) Klinefelter’s syndrome

38. The male has a mutation in his mitochondria. During segregation, the mutation is found in
a) None of the progeny 

b) One third of progeny
c) Half of progeny 

d) Whole of progeny

39. The term mutation was given by
a) De Vries

 b) Mendel 

c) Darwin 

d) Lamarck

40. What is correct?
a) Monosomy and nullisomy are two types of euploidy
b) Polyploidy is more common in animals than in plants
c) Polyploidy occur due to failure in separation of complete sets of chromosomes
d) 2n – 1 is trisomy

41. What is true in case of Honey Bee?
a) Male diploid, female haploid

 b) Male diploid, female diploid
c) Male haploid, female haploid 

d) Male haploid, female diploid

42. Down’s syndrome and Turner’s syndrome are sue to respectively
a) Monosomic and nullisomy conditions 

b) Trisomic and monosomic conditions
c) Monosomic and trisomy conditions 

d) Trisomic and tetrasomic conditions

43. Failure of separation of sister chromatids is
a) Fusion 

b) Non disjunction
c) Complementation 

d) Interference

44. Rearrangement of genes occurs due to
a) Translocation and duplication

 b) translocation and deficiency
c) Deletion and deficiency 

d) translocation and inversion

45. Sex chromosomes of birds are
a) ZZ – ZW 

b) ZZ – WW 

c) XX – XY

 d) XO – XX

46. An individual with cd genes was crossed with wild type ++. On test crossing F1, the progeny was +c 105, cd 880 and ++ 900. Distance between cd genes is
a) 11 map units 

b) 5.5 map units
c) 44 map units 

d) 88 map units

47. When yellow round heterozygous Pea plants are self-fertilized, the frequency of occurrence of RrYY genotype among the offspring is
a) 9/16 

b) 3/16 

c) 2/16 

d) 6/16

48. Recessive character is expressed in
a) F0 

b) F1 

c) F2

 d) Never expressed

49. The frequency of recombination between gene present on the same chromosome as a measure of the distance between genes was explained by
a) Sutton Boveri

 b) T. H. Morgan
c) Gregor J. Mendel

 d) Alfred Sturtevant

50. The movement of a gene from one linkage group to another is called
a) Translocation

 b) crossing over
c) Inversion

 c) duplication

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ANSWER KEY- PRINCIPLES OF INHERITANCE AND VARIATIONS
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