Question

Some mitochondria use a second codon, in addition to AUG, to specify Met. Which codon(s) is (are) most likely to be used this way?

Short answer

In humans, AUA and AUU can be alternately used as start codons along with the AUG start codon.

Step-by-step solution

Definition of Concept

A codon is a group of three DNA or RNA nucleotides that codes for a particular amino acid or protein synthesis halt signal. Four nucleotides make up the language of DNA and RNA molecules, while twenty amino acids make up the language of protein molecules.

Find the codon(s) is (are) most likely to be used this way

Some mitochondria use a second or alternate codon, in addition to AUG, to specify Met or methionine amino acid. AUG is read as Met as a start codon in humans, but AUA and AUU can also alternate as Start codons. Start codons in prokaryotes can be GUG or UUG.