Question

a protein called gef - h₁ is known to control immune responses to certain viruses such as influenza a. gef - h₁ is best classified as which kind of protein?

a structural protein
an antibody
an enzyme
a messenger protein

Explanation:

• Structural proteins provide physical support (e.g., collagen). GEF - H₁'s role is not structural.
• Antibodies are Y - shaped proteins that directly bind to antigens. GEF - H₁ controls immune responses, not direct antigen binding like antibodies.
• Enzymes catalyze chemical reactions. There is no indication GEF - H₁ is a catalyst here.
• Messenger proteins (also known as signaling proteins) regulate biological processes. Since GEF - H₁ controls immune responses (a biological process regulation), it fits the role of a messenger protein.

Answer:

a messenger protein