Please someone help me please (The codon CUU codes for the amino acid leu which is short for leucine. Which change in base pair would not affect the protein chain?)

any change at the third codon position

Explanation:

The genetic code is considered to be degenerate because a single amino acid may be coded for more than one codon. In this case, Leucine (Leu) is an amino acid that can be encoded by four different codons: CUU, CUC, CUA and CUG codons. In consequence, all nucleotide changes (mutations) at the third codon position don't affect the synthesis of Leu. This type of mutation that does not alter the sequence of amino acids is called silent mutation.

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.

the endomembrane system i think