Heredity – 50 Hard MCQs

Heredity – 50 Hard MCQs

Mendel’s Experiments & Laws

1. Mendel is known as the father of genetics because:

(a) He discovered DNA

(b) He proposed laws of inheritance

(c) He explained cell division

(d) He invented microscope

2. Mendel performed his experiments on:

(a) Maize

(b) Wheat

(c) Garden pea

(d) Rice

3. Which feature made pea plant suitable for Mendel’s experiments?

(a) Short life cycle

(b) Large number of seeds

(c) Clear contrasting characters

(d) All of these

4. The law of segregation is also known as:

(a) Law of purity of gametes

(b) Law of dominance

(c) Law of independent assortment

(d) Blending theory

5. Law of independent assortment is applicable when:

(a) One gene is involved

(b) Two or more genes are involved

(c) Asexual reproduction occurs

(d) There is incomplete dominance

6. In monohybrid cross, the F2 phenotypic ratio is:

(a) 1:2:1

(b) 9:3:3:1

(c) 3:1

(d) 2:1

7. In dihybrid cross, the F2 phenotypic ratio is:

(a) 3:1

(b) 9:3:3:1

(c) 1:2:1

(d) 1:1

8. Mendel’s law of dominance explains:

(a) Recessive traits disappear in F1

(b) Dominant trait masks recessive trait

(c) Genes blend together

(d) Traits skip generations

9. Which of the following is a monohybrid cross?

(a) Tt × Tt

(b) TtRr × TtRr

(c) TTRR × ttrr

(d) AaBb × aabb

10. Which character pair was NOT studied by Mendel?

(a) Tall/short stem

(b) Round/wrinkled seed

(c) Red/white flower in pea

(d) Green/yellow seed

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Genes, Chromosomes, DNA

11. Genes are located on:

(a) Nucleus

(b) Chromosomes

(c) Ribosomes

(d) RNA

12. The physical expression of a gene is called:

(a) Genotype

(b) Phenotype

(c) Allele

(d) Trait

13. Alternate forms of a gene are called:

(a) Traits

(b) Characters

(c) Alleles

(d) Genotype

14. Which molecule carries hereditary information?

(a) RNA

(b) DNA

(c) Protein

(d) Lipid

15. The number of pairs of chromosomes in humans is:

(a) 22

(b) 23

(c) 46

(d) 44

16. A human gamete contains how many chromosomes?

(a) 22

(b) 23

(c) 44

(d) 46

17. The process of formation of gametes is:

(a) Mitosis

(b) Meiosis

(c) Fertilization

(d) Budding

18. DNA fingerprinting is based on:

(a) Unique DNA sequence

(b) RNA code

(c) Protein structure

(d) Enzyme activity

19. The functional unit of heredity is:

(a) Chromosome

(b) Gene

(c) DNA

(d) Protein

20. Which one determines sex of child?

(a) Egg

(b) Sperm

(c) Both equally

(d) Cytoplasm

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Variation & Evolution

21. Variation is important because it:

(a) Leads to mutation

(b) Provides adaptability

(c) Causes disease

(d) Reduces diversity

22. A sudden heritable change in DNA is called:

(a) Recombination

(b) Mutation

(c) Evolution

(d) Variation

23. The ultimate source of variation is:

(a) Mutation

(b) Fertilization

(c) Reproduction

(d) DNA copying

24. Evolution occurs due to:

(a) Mutation

(b) Natural selection

(c) Variation

(d) All of these

25. Who gave the theory of natural selection?

(a) Lamarck

(b) Mendel

(c) Darwin

(d) Morgan

26. Vestigial organs are:

(a) Fully functional organs

(b) Non-functional organs

(c) Newly developed organs

(d) None

27. Example of homologous organs is:

(a) Wings of bird and bat

(b) Wings of insect and bird

(c) Flipper of whale and fin of fish

(d) Eye of octopus and man

28. Example of analogous organs is:

(a) Forelimb of human and horse

(b) Wings of bat and wings of bird

(c) Thorns of Bougainvillea and tendril of Cucurbita

(d) Heart of man and rabbit

29. Fossils provide:

(a) Evidence of past life

(b) Proof of evolution

(c) Age of organisms

(d) All of these

30. Which technique helps in determining age of fossils?

(a) Carbon dating

(b) Fossilization

(c) X-ray diffraction

(d) DNA test

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Sex Determination

31. Sex of human baby depends on contribution of:

(a) X chromosome from mother

(b) Y chromosome from father

(c) X from father

(d) Both X and Y from mother

32. Female child inherits which chromosome combination?

(a) XX

(b) XY

(c) YY

(d) XO

33. Male child inherits:

(a) XX

(b) XY

(c) YY

(d) XO

34. Who determines sex of child?

(a) Mother only

(b) Father only

(c) Both equally

(d) Environment

35. Probability of child being male or female is:

(a) 25%

(b) 50%

(c) 75%

(d) 100%

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Applied Genetics

36. Hybridisation results in:

(a) Pure line

(b) More variation

(c) Less variation

(d) No variation

37. The cross between tall pea plant (TT) and dwarf pea plant (tt) produces:

(a) All tall

(b) All dwarf

(c) Half tall half dwarf

(d) 3 tall 1 dwarf

38. Incomplete dominance was first studied in:

(a) Pea plant

(b) Maize

(c) Snapdragon

(d) Rice

39. Haemophilia is a:

(a) Dominant trait

(b) Recessive trait

(c) Sex-linked disorder

(d) Both b and c

40. Colour blindness is caused due to:

(a) Autosomal mutation

(b) Sex-linked mutation

(c) Dominant gene

(d) Recessive gene on Y

41. In sickle-cell anaemia, the defect lies in:

(a) DNA

(b) RNA

(c) Haemoglobin molecule

(d) Chromosome number

42. Which of the following is NOT inherited?

(a) Eye colour

(b) Blood group

(c) Intelligence

(d) Speaking English

43. Blood group in humans is determined by:

(a) Chromosome 21

(b) Chromosome 9

(c) Chromosome X

(d) Chromosome Y

44. Which of the following shows multiple alleles?

(a) Haemophilia

(b) Blood group

(c) Sickle-cell anaemia

(d) Colour blindness

45. In F2 generation of monohybrid cross, the genotypic ratio is:

(a) 1:2:1

(b) 9:3:3:1

(c) 3:1

(d) 1:1

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Miscellaneous

46. Who coined the term “gene”?

(a) Mendel

(b) Johannsen

(c) Morgan

(d) Watson

47. Chromosome theory of inheritance was proposed by:

(a) Mendel

(b) Morgan and Sutton

(c) Darwin

(d) Lamarck

48. Which organelle is called “powerhouse of cell” and has its own DNA?

(a) Nucleus

(b) Ribosome

(c) Mitochondria

(d) Lysosome

49. Which inheritance is influenced by environment?

(a) Genetic

(b) Acquired characters

(c) Mutation

(d) Hybridisation

50. The human genome project was completed in:

(a) 1995

(b) 2001

(c) 2003

(d) 2010

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✅ Answer Key

1-b, 2-c, 3-d, 4-a, 5-b

6-c, 7-b, 8-b, 9-a, 10-c

11-b, 12-b, 13-c, 14-b, 15-b

16-b, 17-b, 18-a, 19-b, 20-b

21-b, 22-b, 23-a, 24-d, 25-c

26-b, 27-a, 28-b, 29-d, 30-a

31-b, 32-a, 33-b, 34-b, 35-b

36-b, 37-a, 38-c, 39-c, 40-b

41-c, 42-d, 43-b, 44-b, 45-a

46-b, 47-b, 48-c, 49-b, 50-c