Question

Which one of the following pairs of codons is correctly matched with their function or the signal for the particular amino acid?

• A. AUG, ACG – start/methionine
• B. UAG, UGA – stop
• C. GUU, GCU – alanine
• D. UUA, UCA – leucine

Answer 1

The correct option is B

UAG, UGA – stop

The correct option is B.

The explanation for the correct option:

1. A stop codon is a triplet of nucleotides found in messenger RNA that signifies the end of translation in the genetic code.
2. They are also referred to as termination codons.
3. Stop codons do not code for any amino acids.
4. There are three types of stop codons: UAG, UGA, and UAA.
5. Stop codons mark the end of translation by binding release factors, which lead to the dissociation of the ribosomal units and the release of the amino acid chain.

The explanation for the incorrect option:

Option A:

1. The first codon that ribosomes translate is the start codon of a messenger RNA (mRNA) transcript.
2. In eukaryotes, the start codon always codes for methionine.
3. AUG is the most common start codon.

Option C:

1. Alanine is an amino acid that is used in the production of proteins.
2. DNA strand base coding GCT, GCC, GCA, and GCG are alanine triplets.

Option D:

1. Leucine is a dietary amino alkanoic acid that can directly increase the production of myofibrillar muscle protein.
2. Within the protein chain, there are six distinct codons, each of which can eventually create a leucine. CTC, CTA, and CTG, for example.

Final answer: UAG, UGA – stop pairs of codons are correctly matched with their function or the signal for the particular amino acid