Question

what monomer is composed of a phosphate bonded to a sugar bonded to a nitrogen base?
a. amino acid
b. fatty acid
c. nucleotide
d. monosaccharide

Explanation:

To solve this, we analyze each option:

• Option A: Amino acids are the monomers of proteins, consisting of an amino group, carboxyl group, and R - group, not matching the given structure.
• Option B: Fatty acids are part of lipids (like in triglycerides or phospholipids), with a long hydrocarbon chain and a carboxyl group, not having phosphate - sugar - nitrogen base structure.
• Option C: Nucleotides are the monomers of nucleic acids (DNA and RNA). Their structure is a phosphate group bonded to a sugar (deoxyribose in DNA, ribose in RNA) which is bonded to a nitrogen - containing base (adenine, guanine, cytosine, thymine in DNA; uracil instead of thymine in RNA). This matches the description.
• Option D: Monosaccharides are the monomers of carbohydrates (like glucose, fructose), and their structure is a simple sugar molecule, not including phosphate and nitrogen base.

Answer:

C. nucleotide