A biochemistry student lists features of the genetic code. Which statement about the code is correct?
- A It is degenerate, since most amino acids are specified by more than one codon ✓
- B It is ambiguous, since each codon specifies more than one amino acid
- C It contains 64 codons, all of which specify amino acids
- D It differs substantially between bacteria and humans
Correct answer: A. It is degenerate, since most amino acids are specified by more than one codon
Explanation
The genetic code is degenerate because multiple codons can encode the same amino acid, usually differing only at the third position, which relates to wobble pairing in the anticodon. The code is unambiguous because each single codon specifies exactly one amino acid, ruling out option B. Of the 64 codons, three (UAA, UAG, UGA) are stop signals rather than amino acid codons, and the code is nearly universal across bacteria and humans, with only rare exceptions such as mitochondrial codes.
Reference: Lippincott's Illustrated Reviews: Biochemistry, 8th ed.
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