Question

A chemical binds to a protein composed of a single polypeptide chain and prevents the formation of an alpha helix that is typically formed in the absence of the chemical. Which of the following best describes the effect the chemical has on the structure of the protein? (A) The primary structure held together by covalent bonds is affected. (B) The secondary structure held together by hydrogen bonds is affected. (C) The secondary, tertiary, and quaternary structures are affected. (D) All levels of protein structure are affected.

Answer 1

Option (B) correctly describes the effect of the chemical, which impacts the secondary structure held together by hydrogen bonds by preventing the formation of an alpha helix in the protein structure.

Step-by-step explanation:

The structure of proteins can be categorized into several levels: primary, secondary, tertiary, and quaternary structures. In the scenario where a chemical prevents the formation of an alpha helix in a protein made of a single polypeptide chain, the impact would be on the secondary structure of the protein. The alpha helix is a type of secondary structure that is maintained by hydrogen bonds between the amino acids in the polypeptide chain. Thus, option (B) The secondary structure held together by hydrogen bonds is affected, is the most accurate description of the chemical's effect on the protein structure. This disruption to the secondary structure could potentially influence the tertiary and possibly even the quaternary structures if the protein subunits were to interact. However, the chemical specifically targets the formation of the alpha helix, directly impacting secondary structure.