Question

the nucleotide of dna is one large molecule composed of three smaller molecules. which of the following sets of molecules bond together to form a nucleotide?
○a deoxyribose, a nitrogen base, a phosphate group
○b a nitrogen atom, a phosphate atom, and a five - carbon sugar
○c adenine, thymine, and cytosine
○d a purine, a pyrimidine, and a five - carbon sugar

Explanation:

• DNA核苷酸由脱氧核糖（deoxyribose）、含氮碱基（nitrogen base）和磷酸基团（phosphate group）组成。
• 选项B中说的是原子（atom），不是分子（molecule），错误。
• 选项C中只是部分含氮碱基，不全面，错误。
• 选项D表述不准确，不是简单的嘌呤（purine）、嘧啶（pyrimidine）和五碳糖组合，错误。

Answer:

A. deoxyribose, a nitrogen base, a phosphate group