Question

What is the activated intermediate during the dehydration synthesis of nucleic acids?

Answer 1

The activated intermediate during the dehydration synthesis of nucleic acids is the phosphodiester bond.

Step-by-step explanation:

The activated intermediate during the dehydration synthesis of nucleic acids is a phosphodiester bond. This bond is formed by the reaction between the phosphate group of one nucleotide and the sugar group of another nucleotide, resulting in the formation of a backbone of the nucleic acid.

For example, in DNA synthesis, the 3' hydroxyl group of the sugar in one nucleotide attacks the α-phosphorous of the triphosphate group of another nucleotide, leading to the elimination of a pyrophosphate molecule and the formation of the phosphodiester bond.

This process continues, with the addition of new nucleotides and the formation of phosphodiester bonds, to build the nucleic acid strand.

Answer 2

The activated intermediate during the dehydration synthesis of nucleic acids is a nucleotide triphosphate, which provides the energy needed for the synthesis and elongation of the nucleic acid chain.

Step-by-step explanation:

The activated intermediate during the dehydration synthesis of nucleic acids is a nucleotide triphosphate. This molecule serves as the starting material for nucleic acid synthesis, where enzymes like DNA polymerase facilitate the formation of a phosphodiester bond.

During this process, the -OH group at the 3' position of deoxyribose in one nucleotide attacks the a-phosphorous of the triphosphate group at the 5' position of the next nucleotide. This forms the phosphodiester linkage between the nucleotides with the concomitant release of pyrophosphate. The pyrophosphate then breaks down into two phosphate units, which drives the reaction to completion and makes it irreversible.

Thus, the nucleotide triphosphate acts not only as a monomer but also as an activated chemical intermediate that provides the energy needed for the dehydration synthesis required to extend the nucleic acid chain.