Which biological process can be influenced by methylation patterns?

Methylation patterns play a crucial role in gene expression. In eukaryotic cells, DNA methylation typically occurs on cytosine bases in the context of cytosine-guanine (CpG) dinucleotides. When methyl groups are added to DNA, they can influence the transcriptional activity of genes by preventing the binding of transcription factors and other proteins that are necessary for gene activation. This means that high levels of methylation in specific regions can lead to gene silencing, while low levels can promote gene expression.

In this way, methylation serves as a regulatory mechanism that can turn genes on or off without altering the underlying DNA sequence itself, thereby affecting an organism's phenotype and response to environmental changes. This modification is a key mechanism in processes such as development, differentiation, and even cellular responses to stress.

The other processes listed—cell respiration, photosynthesis, and protein translation—are essential metabolic and biosynthetic pathways that are not directly regulated by DNA methylation. Instead, those processes are more directly influenced by various other factors, such as enzyme activity, substrate availability, and cellular conditions.