Question

based on the information provided, drag and drop the correct enzyme to each key step of the excision repair process. each option will only be used once, and not all options will be used.
the double helix at the site of damage is opened (hydrogen bonds are broken to make the dna at the site single - stranded)
nucleotides on the damaged strand are removed.
new nucleotides are added, complementary to those on the intact (undamaged) strand.
phosphodiester linkages are re - established on either end of the repair, to link the newly synthesized section with the flanking sequences.
dna ligase dna polymerase dna helicase dna endonuclease dna exonuclease primase

Explanation:

• DNA helicase: Unwinds the DNA double - helix by breaking hydrogen bonds, making the DNA single - stranded at the damage site.
• DNA endonuclease: Cuts (removes) the nucleotides on the damaged strand.
• DNA polymerase: Adds new nucleotides complementary to the undamaged strand.
• DNA ligase: Re - establishes phosphodiester linkages to connect the newly synthesized section with the flanking sequences.

Answer:

1. DNA helicase
2. DNA endonuclease
3. DNA polymerase
4. DNA ligase