Proteins involved in DNA replication

Question 1

DNA polymerase

Answer 1

Catalyzes the addition of nucleotides to the 3′ end of a growing strand of DNA using a parent DNA strand as a template; proofreads nucleotides added to newly synthesized DNA and removes those that are paired incorrectly

Question 2

dna helicase

Answer 2

Uses the energy of ATP hydrolysis to pry apart the DNA double helix ahead of the replication fork

Question 3

single-strand DNA binding protein

Answer 3

Binds to single-stranded DNA exposed by DNA helicase, preventing base pairs from re-forming before the lagging strand can be replicated

Question 4

dna topoisomerase

Answer 4

Produces transient breaks in one strand of the DNA double helix to relieve the tension built up by the unwinding of DNA ahead of the DNA helicase; reseals breaks after DNA has relaxed

Question 5

sliding clamp

Answer 5

Keeps DNA polymerase attached to the template, allowing the enzyme to move along without falling off as it synthesizes new DNA

Question 6

clamp loader

Answer 6

Uses the energy of ATP hydrolysis to lock the sliding clamp onto DNA

Question 7

primase

Answer 7

Synthesizes RNA primers along the lagging-strand template

Question 8

dna ligase

Answer 8

Uses the energy of ATP hydrolysis to join Okazaki fragments made on the lagging strand template