Genetic code — NEET Biology Questions

Practice 47 questions on Genetic code from Molecular Basis of Inheritance (NCERT Class 12, Chapter 5). Free samples below — get all 47 in the app.

47 Questions Molecular Basis of Inheritance Class 12

Sample Questions — Genetic code

Try 5 questions below from Genetic code. Get all 47 in the MedicNEET app.

MCQ
The poly(U) RNA sequence was used by Nirenberg to determine that:
  • A. UUU codes for methionine
  • B. UUU codes for leucine
  • C. UUU codes for phenylalanine
  • D. UUU codes for tryptophan
✅ Correct Answer: C
Nirenberg used synthetic RNA to show UUU codon specifies phenylalanine.
MCQ
6. Choose the correct statements: I. Codons are read from 3′ → 5′ direction II. AUG is both start codon and codes methionine III. UGA is a stop codon IV. Codon usage is species-specific
  • A. II and III only
  • B. I and IV only
  • C. II, III, and IV
  • D. I, II, and III
✅ Correct Answer: A
Codons are read from 5′ → 3′ and code is universal, not species-specific.
👆 Want all 47 Genetic code questions? Get them in the app. Download MedicNEET →
MCQ
Why was Khorana’s method important in confirming the triplet nature of codons?
  • A. It used radioactive labeling for codon sequences
  • B. It allowed controlled synthesis of codon sequences
  • C. It confirmed the double helix
  • D. It demonstrated translation
✅ Correct Answer: B
Khorana could assign codons to amino acids using defined synthetic RNAs.
MCQ
What characteristic of the genetic code ensures that each codon codes for only one amino acid?
  • A. Universality
  • B. Degeneracy
  • C. Non-ambiguity
  • D. Triplet nature
✅ Correct Answer: C
Genetic code is non-ambiguous—each codon specifies only one amino acid.
MCQ
11. Assertion (A): Genetic code is regenerate. Reason (R): More than one codon can code for a single amino acid.
  • A. Both A and R are true, and R is the correct explanation of A
  • B. Both A and R are true, but R is not the correct explanation of A
  • C. A is true, R is false
  • D. A is false, R is true
✅ Correct Answer: D
Genetic code is degenerate. Degeneracy refers to multiple codons specifying the same amino acid.

Practice All 47 Questions from Genetic code

You've seen 5 sample questions. Get all 47 with detailed NCERT-mapped explanations in the MedicNEET app.

📲 Download MedicNEET Free
Available on Android • 12,771 Biology Questions • 3 Formats
📲 Download MedicNEET — 12,771 Biology Questions