Question

which best describes a codon?
a a codon is a triplet of three bases in the mrna that codes for a specific amino acid.
b a codon is a triplet of three bases in the gene sequence.
c a codon is a triplet of three bases in the mrna that codes for a specific gene.
d a codon is a triplet of three bases in the dna that codes for a specific amino acid.

Explanation:

To determine the correct description of a codon, we recall the definition: a codon is a sequence of three nucleotides (bases) in mRNA. Each codon codes for a specific amino acid (or a start/stop signal). Let's analyze each option:

• Option a: States a codon is a triplet of three bases in mRNA that codes for a specific amino acid. This matches the definition.
• Option b: A codon is not in the gene sequence (DNA) directly; it's in mRNA. So this is incorrect.
• Option c: Codons code for amino acids, not genes. So this is incorrect.
• Option d: Codons are in mRNA, not DNA (DNA has codons' templates called triplets, but codons themselves are in mRNA). So this is incorrect.

Answer:

a. A codon is a triplet of three bases in the mRNA that codes for a specific amino acid.