How can different subunits of a protein's quaternary structure arise?

The correct answer indicates that different subunits of a protein's quaternary structure can arise from multiple genes or from post-translational cleavage. This reflects the complexity of protein assembly and diversity.

Proteins with quaternary structure are made up of two or more polypeptide chains, known as subunits, which can each be encoded by different genes. This allows for greater variability and functionality in proteins, as different gene products can come together to form a multi-subunit complex. For example, hemoglobin consists of different polypeptide chains (subunits) that are encoded by separate genes, allowing for variations based on developmental or environmental conditions.

Furthermore, post-translational modifications can also lead to the formation of different subunits, such as the cleavage of precursor proteins into active forms. This process can involve removing parts of the protein that were not needed in the mature functional state, effectively creating different proteins from a single precursor.

In contrast, other options focus on singular mechanisms that are not comprehensive enough to account for the complexity of quaternary structure formation. While mutations in a single gene can lead to functional changes, they do not encompass the full range of how different subunits can be organized in quaternary structures. Environmental factors can influence