1. Mutation is defined as

A. Gradual change in traits B. Sudden heritable change in DNA C. Change in environment D. Change in RNA only

✅ Answer: B

📘 Explanation: Mutation is a sudden, stable and heritable change in genetic material.

2. The ultimate source of genetic variation is

A. Recombination B. Hybridisation C. Mutation D. Natural selection

✅ Answer: C

📘 Explanation: Mutations create new alleles.

3. A mutation affecting a single base pair is called

A. Chromosomal mutation B. Genome mutation C. Point mutation D. Polyploidy

✅ Answer: C

📘 Explanation: Gene or point mutations affect one nucleotide.

4. Sickle cell anaemia is caused due to

A. Deletion mutation B. Inversion mutation C. Point mutation D. Polyploidy

✅ Answer: C

📘 Explanation: Single base substitution causes sickle cell anaemia.

5. In sickle cell anaemia, the codon GAG changes to

A. GAA B. GTG C. GGG D. GAC

✅ Answer: B

📘 Explanation: Glutamic acid is replaced by valine.

6. Which amino acid is replaced in sickle cell anaemia?

A. Glycine B. Alanine C. Valine D. Glutamic acid

✅ Answer: D

📘 Explanation: Normal haemoglobin contains glutamic acid.

7. Insertion or deletion of a base pair leads to

A. Silent mutation B. Missense mutation C. Frameshift mutation D. Neutral mutation

✅ Answer: C

📘 Explanation: Reading frame changes.

8. Which mutation does NOT change amino acid sequence?

A. Frameshift B. Missense C. Nonsense D. Silent

✅ Answer: D

📘 Explanation: Silent mutations code for same amino acid.

9. Which mutation results in premature stop codon?

A. Missense B. Silent C. Nonsense D. Frameshift

✅ Answer: C

📘 Explanation: Nonsense mutation ends protein synthesis early.

10. Chromosomal mutations involve

A. Single gene B. Whole genome C. Structure of chromosome D. RNA molecule

✅ Answer: C

📘 Explanation: Structural change in chromosome.

11. Loss of a chromosomal segment is called

A. Duplication B. Deletion C. Inversion D. Translocation

✅ Answer: B

📘 Explanation: Deletion removes part of chromosome.

12. Reversal of a chromosomal segment is

A. Translocation B. Duplication C. Inversion D. Deletion

✅ Answer: C

📘 Explanation: Inversion reverses orientation.

13. Exchange of segments between non-homologous chromosomes is

A. Inversion B. Deletion C. Duplication D. Translocation

✅ Answer: D

📘 Explanation: Translocation involves different chromosomes.

14. Increase in gene dosage occurs due to

A. Deletion B. Duplication C. Inversion D. Frameshift

✅ Answer: B

📘 Explanation: Extra copy increases gene amount.

15. Genome mutations involve change in

A. DNA sequence B. Chromosome structure C. Chromosome number D. Protein synthesis

✅ Answer: C

📘 Explanation: Genome mutation alters chromosome number.

16. Trisomy 21 is an example of

A. Polyploidy B. Aneuploidy C. Euploidy D. Diploidy

✅ Answer: B

📘 Explanation: Gain of one chromosome.

17. Down syndrome is caused by

A. Deletion B. Translocation C. Trisomy 21 D. Monosomy X

✅ Answer: C

📘 Explanation: Extra chromosome 21.

18. Turner syndrome has the karyotype

A. XX B. XO C. XY D. XXY

✅ Answer: B

📘 Explanation: Monosomy of X chromosome.

19. Klinefelter syndrome shows

A. XO B. XX C. XXY D. XYY

✅ Answer: C

📘 Explanation: Extra X chromosome in males.

20. Polyploidy is common in

A. Animals B. Humans C. Plants D. Bacteria

✅ Answer: C

📘 Explanation: Plants tolerate polyploidy well.

21. Mutations occurring naturally are called

A. Induced B. Artificial C. Spontaneous D. Lethal

✅ Answer: C

📘 Explanation: Occur without external agents.

22. Mutations caused by mutagens are

A. Spontaneous B. Induced C. Natural D. Neutral

✅ Answer: B

📘 Explanation: External agents induce mutation.

23. UV radiation causes

A. Frameshift mutation B. Thymine dimers C. Polyploidy D. Translocation

✅ Answer: B

📘 Explanation: UV causes thymine–thymine bonding.

24. Which is a chemical mutagen?

A. X-rays B. Gamma rays C. Nitrous acid D. UV rays

✅ Answer: C

📘 Explanation: Nitrous acid alters base pairing.

25. Viruses can cause mutation by

A. Crossing over B. Transposition C. Infection D. Recombination

✅ Answer: B

📘 Explanation: Viruses act as biological mutagens.

26. Somatic mutations

A. Are inherited B. Occur in germ cells C. Cause evolution D. Are not inherited

✅ Answer: D

📘 Explanation: Affect body cells only.

27. Germinal mutations

A. Are not passed to offspring B. Occur in somatic cells C. Cause evolution D. Are lethal always

✅ Answer: C

📘 Explanation: Germ cell mutations are inherited.

28. Cancer is often caused by

A. Germinal mutation B. Somatic mutation C. Silent mutation D. Neutral mutation

✅ Answer: B

📘 Explanation: Cancer results from uncontrolled somatic mutations.

29. Which mutation is most harmful?

A. Silent B. Missense C. Frameshift D. Neutral

✅ Answer: C

📘 Explanation: Frameshift alters entire protein.

30. Which mutation does not affect phenotype?

A. Lethal B. Neutral C. Frameshift D. Nonsense

✅ Answer: B

📘 Explanation: Neutral mutations show no effect.

31. Mutations help organisms by

A. Reducing variation B. Preventing evolution C. Creating variation D. Eliminating genes

✅ Answer: C

📘 Explanation: Variation aids adaptation.

32. Which mutation changes one amino acid?

A. Silent B. Missense C. Nonsense D. Frameshift

✅ Answer: B

📘 Explanation: Missense mutation replaces one amino acid.

33. Deamination affects which base?

A. Adenine B. Guanine C. Cytosine D. Thymine

✅ Answer: C

📘 Explanation: Cytosine deaminates to uracil.

34. Which is NOT a chromosomal mutation?

A. Deletion B. Duplication C. Inversion D. Point mutation

✅ Answer: D

📘 Explanation: Point mutation is gene-level.

35. Polyploid wheat is an example of

A. Aneuploidy B. Genome mutation C. Gene mutation D. Point mutation

✅ Answer: B

📘 Explanation: Change in chromosome sets.

36. Frameshift mutation occurs due to

A. Substitution B. Translocation C. Insertion or deletion D. Duplication

✅ Answer: C

37. Mutation producing stop codon early is

A. Silent B. Missense C. Nonsense D. Neutral

✅ Answer: C

38. Aneuploidy arises due to

A. Crossing over B. Nondisjunction C. Mutation repair D. Fertilisation

✅ Answer: B

39. Which is a beneficial mutation?

A. Genetic disorder B. Cancer C. Antibiotic resistance D. Lethal mutation

✅ Answer: C

40. Which mutation affects chromosome number?

A. Deletion B. Duplication C. Aneuploidy D. Inversion

✅ Answer: C

41. Mutation rate can be increased by

A. DNA repair B. Mutagens C. Meiosis D. Fertilisation

✅ Answer: B

42. Which mutation leads to Cri du chat syndrome?

A. Duplication B. Deletion of 5p C. Translocation D. Inversion

✅ Answer: B

43. Which mutation is least harmful?

A. Frameshift B. Nonsense C. Missense D. Silent

✅ Answer: D

44. Transposons cause mutation by

A. Base substitution B. Jumping genes C. Crossing over D. Replication

✅ Answer: B

45. Mutation is essential for

A. Survival only B. Reproduction only C. Evolution D. Growth

✅ Answer: C

46. Mutagens act on

A. Protein B. Lipid C. DNA D. Carbohydrate

✅ Answer: C

47. Which mutation alters phenotype severely?

A. Silent B. Neutral C. Frameshift D. Conservative

✅ Answer: C

48. Which disorder is due to point mutation?

A. Down syndrome B. Turner syndrome C. Sickle cell anaemia D. Klinefelter syndrome

✅ Answer: C

49. Structural chromosome mutations do NOT include

A. Inversion B. Duplication C. Translocation D. Aneuploidy

✅ Answer: D

50. Mutation causing change in codon but same amino acid is

A. Missense B. Nonsense C. Silent D. Frameshift

✅ Answer: C

⬇ Download Full MCQ – Mutation (PDF)

Concepts: Mutation