SAT Subject Biology Practice Question 158: Answer and Explanation
8. What are the three structural components of a nucleotide?
A. A carboxyl, a sugar, and a phosphate
B. A phosphate, an amino acid, and a carboxyl
C. An amino acid, a carboxyl, and a phosphate
D. A sugar, a phosphate, and a nitrogenous base
E. A nitrogenous base, an amino acid, and a sugar
Correct Answer: D
Nucleic acids are formed from mononucleotide polymers. A mononucleotide is one unit that is composed of three components: a sugar; a phosphate, which binds to the sugar in order to create the phosphodiester bond that unites nucleotides into a nucleic acid chain; and a nitrogen base, which pairs with other bases to form a readable sequence.