Mechanism of DNA Replication Flashcards

A set of vocabulary flashcards covering the enzymes, proteins, and mechanisms involved in DNA replication based on the lecture notes.

Nucleotide triphosphates

The actual form of free DNA nucleotides before they are incorporated into a new strand.

Phosphodiester bond

A bond formed with the $OH$ group at the $3'$ end by DNA Polymerase III using energy supplied by the release of two phosphate groups.

Single-stranded binding proteins (SSBs)

Proteins that prevent DNA strands from annealing back together by blocking hydrogen bonds between bases to keep strands separated.

DNA gyrase

Also called topoisomerases; an enzyme that relieves tension caused by the unwinding of DNA by cutting both strands, allowing them to swivel, and then re-attaching them.

DNA helicase

An enzyme that separates and unwinds the double helix by breaking hydrogen bonds between base pairs.

DNA Polymerase III

An enzyme that binds to RNA primers and assembles DNA nucleotides to the new or elongating strand in the $5'$ to $3'$ direction as it moves towards the replication fork.

Okazaki fragments

Small segments used to build the lagging strand.

RNA primase

An enzyme that adds RNA nucleotides to initiate the start of a new complementary strand; these RNA primers serve as a "binding site" for DNA Polymerase III.

DNA Polymerase I

An enzyme that removes RNA primers and replaces them with DNA nucleotides in a $5'$ to $3'$ direction; it also "feels" for and corrects mis-matched base pairs.

DNA ligase

An enzyme that joins pieces or Okazaki fragments of the lagging strand together.

DNA Polymerase II

An enzyme that slowly moves down DNA "feeling" for mis-matched base pairs to make corrections.