Question

which of these molecular structures could be found in a lipid, but not in a carbohydrate, protein, or nucleic acid?
a. a long chain of carbon, oxygen, and nitrogen atoms
b. a long chain made only of carbon and hydrogen atoms
c. a phosphate group joined to a chain of carbon atoms

Explanation:

Carbohydrates are composed of carbon, hydrogen, and oxygen. Proteins contain carbon, hydrogen, oxygen, and nitrogen (and sometimes sulfur). Nucleic acids have carbon, hydrogen, oxygen, nitrogen, and phosphorus. Lipids often have long - hydrocarbon chains (chains made only of carbon and hydrogen atoms), which are not characteristic of the other three macromolecules. Option A is found in proteins, Option C is found in nucleic acids and some lipids.

Answer:

B. a long chain made only of carbon and hydrogen atoms