Question

gether. Remember that these fragments are connected only after the RNA primers at their ends have been removed. Given this information, infer the type of chemical bond whose formation is catalyzed by DNA ligase and whether or not a source of energywill be required to promote this reaction. Explain why DNA ligase and not DNA polymerase is required to join Okazaki fragments.

Answer 1

Explained

Step-by-step explanation:

DNA ligase also catalyzes the formation of a phosphodiester bond between thenucleotides located at the 3′ end of one Okazaki fragment and the 5′ end of the nextOkazaki fragment. Because only a single phosphate group is attached to the 5′carbon atom of the nucleotide at the 5′ end of an Okazaki fragment after theprimer is removed, DNA ligase needs an external source of energy tocatalyze the formation of a phosphodiester bond. Ligase obtains this energy by hydrolyzing ATP.

This lack of a triphosphate group at the 5′ end of an Okazaki fragment also explains why DNA polymerase cannot be used to join Okazaki fragments- DNA polymerase does not hydrolyze ATP and no high-energy bond would be available at the junction of Okazaki fragments, so the DNA polymerase enzyme would have no available energy source to catalyze the formation of a phosphodiester bond