Question

What enzyme forms covalent bonds between restriction fragments?

A) DNA primase
B) DNA helicase
C) single-stranded binding protein
D) DNA polymerase
E) DNA ligase

Answer 1

The enzyme responsible for forming covalent bonds between restriction fragments is DNA ligase, which joins Okazaki fragments during DNA replication. A mutation in DNA ligase would impair this process, affecting the overall integrity of the DNA molecule.

Step-by-step explanation:

The enzyme that forms covalent bonds between restriction fragments is DNA ligase. This enzyme catalyzes the formation of a covalent phosphodiester linkage between the 3'-OH end of one DNA fragment and the 5' phosphate end of another DNA fragment. During DNA replication, DNA ligase is responsible for sealing the gaps between Okazaki fragments on the lagging strand, thereby joining the fragments into a single continuous DNA molecule.

In scenarios where the joining together of Okazaki fragments is impaired due to a mutated enzyme at the replication fork, DNA ligase is the most likely candidate to be affected. This mutation would prevent DNA ligase from effectively performing its role in linking DNA strands, resulting in impaired DNA replication.

DNA ligase is the enzyme that forms covalent bonds between restriction fragments. It catalyzes the formation of a covalent phosphodiester linkage between the 3'-OH end of one DNA fragment and the 5' phosphate end of another DNA fragment. This process is essential in joining the Okazaki fragments during DNA replication.