Which statement about the genetic code is true?

Which statement about the genetic code is true?

• A. Each amino acid is coded by a single codon.
• B. Codons are made of DNA only
• C. The code is degenerate; multiple codons can code for the same amino acid.
• D. Codons code for lipids

Answer: (C)

The main idea here is that the genetic code is degenerate. Codons are read in triplets of RNA bases during translation, and there are 64 possible codons but only 20 standard amino acids (plus start and stop signals). This surplus means most amino acids are specified by more than one codon, giving redundancy in the code. For example, several different codons specify serine or leucine, while some amino acids like methionine have a single codon. This degeneracy helps protect against point mutations and explains why the same amino acid can be coded by multiple codons. Codons are defined in RNA (with U instead of T); during transcription, DNA is copied into mRNA, and translation uses those RNA codons to add the correct amino acids. Codons do not code lipids, and the one-to-one idea is incorrect.

The main idea here is that the genetic code is degenerate. Codons are read in triplets of RNA bases during translation, and there are 64 possible codons but only 20 standard amino acids (plus start and stop signals). This surplus means most amino acids are specified by more than one codon, giving redundancy in the code. For example, several different codons specify serine or leucine, while some amino acids like methionine have a single codon. This degeneracy helps protect against point mutations and explains why the same amino acid can be coded by multiple codons. Codons are defined in RNA (with U instead of T); during transcription, DNA is copied into mRNA, and translation uses those RNA codons to add the correct amino acids. Codons do not code lipids, and the one-to-one idea is incorrect.