Which statement about nucleotides is true?

Which statement about nucleotides is true?

• A. Each nucleotide contains a phosphate group.
• B. Nucleotides never contain ribose.
• C. Nucleotides are identical to nucleosides except for the base.
• D. Nucleotides lack sugar.

Answer: (A)

Nucleotides are the building blocks of nucleic acids and are made of three parts: a sugar, a phosphate group, and a nitrogenous base. The phosphate group is present in every nucleotide and is what links nucleotides together to form the backbone of DNA and RNA through phosphodiester bonds. Because of this, the statement that each nucleotide contains a phosphate group is true. The sugar in nucleotides can be ribose (in RNA) or deoxyribose (in DNA), so nucleotides can contain ribose or deoxyribose depending on the molecule. That’s why saying nucleotides never contain ribose is incorrect. A nucleoside, by contrast, is just sugar plus base and lacks the phosphate group, which is why nucleotides are not identical to nucleosides. Finally, nucleotides do include sugar, so the claim that they lack sugar isn’t accurate.

Nucleotides are the building blocks of nucleic acids and are made of three parts: a sugar, a phosphate group, and a nitrogenous base. The phosphate group is present in every nucleotide and is what links nucleotides together to form the backbone of DNA and RNA through phosphodiester bonds. Because of this, the statement that each nucleotide contains a phosphate group is true.

The sugar in nucleotides can be ribose (in RNA) or deoxyribose (in DNA), so nucleotides can contain ribose or deoxyribose depending on the molecule. That’s why saying nucleotides never contain ribose is incorrect. A nucleoside, by contrast, is just sugar plus base and lacks the phosphate group, which is why nucleotides are not identical to nucleosides. Finally, nucleotides do include sugar, so the claim that they lack sugar isn’t accurate.