Question

Which of the following is most similar in structure to ATP?

Answer 1

The correct answer is : C) an RNA nucleotide.

Explanation:

• Nucleic acids, DNA or deoxyribonucleic acid and RNA or Ribonucleic acid are the biological macro-molecules formed by the polymerization of monomeric units called Deoxy-ribonuclotide and Ribonucleotide respectively.
• Each nucleotide or deoxy-ribonucleotide is comprised of:

1. A pentose sugar, deoxyribose for DNA and ribose for RNA. The Ribose has a hydroxyl group at the 2' carbon position of the sugar molecule. This hydroxyl group is replaced by hydrogen in the deoxyribose sugar.
2. A nitrogenous base, like adenine, guanine, cytosine and thymine (for DNA) and uracil (for RNA) linked to the 1' carbon of the deoxyribose or ribose sugar through glycosidic linkage.
3. One phosphate group which forms a phosphodiester bond in between the 3' carbon of one sugar molecule with the 5' carbon of the next sugar molecule in the nucleic acid polymer.

• An ATP molecule contain:

1. Ribose as the pentose sugar but not deoxyribose.
2. The nitrogenous base here is Adenine.
3. Three phosphate groups, alpha, beta and gamma, linked to each other by two phospho-anhydride bonds and to the ribose sugar by one phosphate-ester bond.

• The ATP molecule loses two of its phosphate groups, the beta phosphate and the gamma phosphate, and forms a phosphodiester bond between the 3' carbon of one ribose sugar molecule and the 5' carbon of the next ribose sugar molecule in the Ribonucleic acid polymer.