Small scale mutations primarily affect what biological process?

Small scale mutations primarily affect protein synthesis. This is because mutations, particularly those that change a single nucleotide (known as point mutations), can alter the sequence of amino acids in a protein. These changes can impact how the ribosomes read mRNA during the translation process and can lead to the production of a dysfunctional protein or one with altered function.

Considering the roles of both DNA replication and gene expression, they may involve mutations as well, but the direct consequence of small scale mutations primarily influences the sequence of the proteins synthesized rather than the processes of replication or expression itself. Cell division is more related to larger genomic changes or chromosomal abnormalities and is less impacted by the minute changes that small scale mutations represent. Thus, the most direct and significant impact of these mutations is conveyed during the process of protein synthesis.