Which of these molecular structures could be found in a lipid, but not in a carbohydrate, protein, or nucleic acid?

Question

Responses

A long chain made only of carbon and hydrogen atoms (hydrocarbon chain)
A long chain made only of carbon and hydrogen atoms (hydrocarbon chain)

A long chain of carbon, nickel, and nitrogen atoms
A long chain of carbon, nickel, and nitrogen atoms

A phosphate group joined to a chain of nitrogen atoms
A phosphate group joined to a chain of nitrogen atoms

An amino group and a carboxyl group bonded together
An amino group and a carboxyl group bonded together

Answer 1

The correct response is:

A long chain made only of carbon and hydrogen atoms (hydrocarbon chain)

Lipid structures typically contain long hydrocarbon chains (such as fatty acids), which are not found in carbohydrates, proteins, or nucleic acids. The other options provided involve components typically associated with proteins (amino group and carboxyl group), nucleic acids (phosphate group), or represent unusual combinations (such as the carbon, nickel, and nitrogen chain that do not represent common biological molecules).