Questions with Correct Verified Answers/ Latest Update
2026.
1. A codon is a sequence of how many nucleotides?
• A) 2
• B) 3
• C) 4
• D) 6
Answer: B) 3
Rationale: The genetic code is a triplet code, with four bases
taken three at a time, giving 64 possible combinations . A codon
is a sequence of three nucleotides on mRNA that specifies a
particular amino acid .
2. How many possible codons can be formed from the four RNA
bases?
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, • A) 16
• B) 32
• C) 48
• D) 64
Answer: D) 64
Rationale: With four bases (A, G, C, U) taken three at a time, the
number of possible codons is 4³ = 64. This provides enough
combinations to code for the 20 standard amino acids plus start
and stop signals .
3. The start codon is:
• A) AUG
• B) UAG
• C) GUG
• D) UGA
Answer: A) AUG
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,Rationale: AUG is the start codon that signals the beginning of
translation and codes for methionine (formylmethionine in
prokaryotes) .
4. How many codons code for amino acids?
• A) 61
• B) 62
• C) 63
• D) 64
Answer: A) 61
Rationale: Of the 64 possible codons, 61 code for amino acids,
while 3 are stop codons that signal termination of translation .
5. The genetic code is described as "degenerate" because:
• A) Some codons do not code for any amino acid
• B) Multiple codons can code for the same amino acid
• C) Codons overlap with each other
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, • D) The code is different in different organisms
Answer: B) Multiple codons can code for the same amino acid
Rationale: Degeneracy (redundancy) in the genetic code means
that most amino acids are specified by more than one codon. This
provides protection against some point mutations .
6. Which of the following is a stop codon?
• A) AUG
• B) UAA
• C) GUG
• D) CUG
Answer: B) UAA
Rationale: The three stop codons are UAA, UAG, and UGA.
These do not code for any amino acid and signal the termination
of translation .
7. The anticodon is located on:
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