Which sugar is present in DNA nucleotides?

Which sugar is present in DNA nucleotides?

• A. Deoxyribose.
• B. Ribose.
• C. Glucose.
• D. Fructose.

Answer: (A)

DNA nucleotides use deoxyribose as their sugar. This five-carbon sugar is called deoxyribose because it lacks an oxygen atom at the 2' position (the 2' carbon has just a hydrogen instead of a hydroxyl group). That small structural difference from ribose, which has a 2' hydroxyl, is what distinguishes DNA from RNA. In DNA, the sugar, a phosphate, and a nitrogenous base form a nucleotide, and nucleotides link through phosphodiester bonds from the 3' end of one sugar to the 5' end of the next. The absence of the 2' hydroxyl on deoxyribose makes the DNA backbone more chemically stable, contributing to DNA’s durability, whereas RNA, with ribose, is more reactive due to the 2' OH. Glucose and fructose are other common sugars, but they are not components of DNA nucleotides.

DNA nucleotides use deoxyribose as their sugar. This five-carbon sugar is called deoxyribose because it lacks an oxygen atom at the 2' position (the 2' carbon has just a hydrogen instead of a hydroxyl group). That small structural difference from ribose, which has a 2' hydroxyl, is what distinguishes DNA from RNA. In DNA, the sugar, a phosphate, and a nitrogenous base form a nucleotide, and nucleotides link through phosphodiester bonds from the 3' end of one sugar to the 5' end of the next. The absence of the 2' hydroxyl on deoxyribose makes the DNA backbone more chemically stable, contributing to DNA’s durability, whereas RNA, with ribose, is more reactive due to the 2' OH. Glucose and fructose are other common sugars, but they are not components of DNA nucleotides.