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 in connective tissues). GEF - H₁ is not described as providing a structural role.
• Antibodies are proteins that specifically bind to antigens (e.g., virus proteins) to neutralize pathogens. GEF - H₁ is said to "control" immune responses, not directly bind to antigens like a typical antibody.
• Enzymes are proteins that catalyze chemical reactions. There is no mention of GEF - H₁ catalyzing a reaction.
• Messenger proteins (also known as signaling proteins) help transmit signals in the body. Controlling immune responses (which involves signaling within the immune system) is consistent with the role of a messenger protein.

Answer:

a messenger protein