Question

which of the following could be a nucleotide of dna?
○ deoxyribose + phosphate group + thymine
○ deoxyribose + phosphate group + uracil
○ ribose + phosphate group + thymine
○ ribose + phosphate group + uracil

Explanation:

To determine a DNA nucleotide, recall: DNA nucleotides have deoxyribose (sugar), a phosphate group, and one of A, T, C, G. RNA has ribose and uracil (U) instead of thymine (T).

• Option 1: Deoxyribose (DNA sugar) + phosphate + thymine (DNA base) → matches DNA nucleotide structure.
• Option 2: Uracil is an RNA base, so invalid for DNA.
• Option 3: Ribose is an RNA sugar, invalid for DNA.
• Option 4: Ribose (RNA sugar) + uracil (RNA base) → RNA nucleotide, not DNA.

Answer:

A. deoxyribose + phosphate group + thymine