Question

Which one of the following is true of the pentoses found in nucleic acids?

• A. C-5 and C-1 of the pentose are joined to phosphate groups by phosphodiester bonds.
• B. C-5 and C-1 of the pentose are joined to a phosphate group and to a nitrogenous base respectively.
• C. The pentoses are always in the furanose forms.
• D. The straight-chain and ring forms undergo constant interconversion.

Answer 1

Answer: (B), (C)

The pentoses are always in the furanose forms.

The pentoses found in nucleic acids are ribose and deoxyribose. The ribose and deoxyribose sugars bind to phosphate group at the C-5, and to the nitrogenous base at C-1.