Question

you arrive late to a biological seminar. however, just as you enter the room, you hear the speaker referring to the amino end and the carboxyl end of a macromolecule. immediately, you know that they are talking about a:
multiple choice
carbohydrate.
protein.
nucleic acid.
lipid.

Explanation:

Proteins are polymers of amino - acids. Each amino - acid has an amino group and a carboxyl group. Proteins have an amino - terminus (amino end) and a carboxyl - terminus (carboxyl end). Carbohydrates, nucleic acids, and lipids do not have such specific "amino end" and "carboxyl end" terminologies in the same context.

Answer:

B. protein