Which statement about codons is accurate?

Which statement about codons is accurate?

• A. A codon is a sequence of four nitrogen bases that codes for one amino acid.
• B. A codon is a sequence of two nitrogen bases that codes for a nucleotide.
• C. A codon is a sequence of three nitrogen bases that codes for one amino acid.
• D. A codon is a sequence of three nitrogen bases that codes for a ribosome.

Answer: (C)

Codons are triplets of nucleotides in mRNA that specify a single amino acid during translation. The genetic code is read in groups of three bases, and each triplet maps to one amino acid (with some triplets serving as start or stop signals). There are 64 possible codons; 61 specify amino acids and 3 are stop codons; the start codon AUG also encodes methionine. Therefore, the statement describing a codon as a sequence of three nitrogen bases that codes for one amino acid is accurate. The other statements misstate the length or what a codon encodes, such as suggesting four bases, two bases, or coding for a ribosome.

Codons are triplets of nucleotides in mRNA that specify a single amino acid during translation. The genetic code is read in groups of three bases, and each triplet maps to one amino acid (with some triplets serving as start or stop signals). There are 64 possible codons; 61 specify amino acids and 3 are stop codons; the start codon AUG also encodes methionine. Therefore, the statement describing a codon as a sequence of three nitrogen bases that codes for one amino acid is accurate. The other statements misstate the length or what a codon encodes, such as suggesting four bases, two bases, or coding for a ribosome.