DNA Replication Glossary

An enzyme that joins Okazaki fragments by catalyzing phosphodiester bonds between adjacent DNA segments, sealing nicks in the backbone.

The enzyme that synthesizes new DNA by adding complementary nucleotides to the 3-prime end of a growing strand. It also has proofreading (exonuclease) activity.

An enzyme that unwinds the DNA double helix by breaking hydrogen bonds between base pairs, using energy from ATP hydrolysis.

Short DNA segments synthesized on the lagging strand during replication, later joined by DNA ligase into a continuous strand.

A specific DNA sequence where replication is initiated. Prokaryotes typically have one; eukaryotes have thousands.

An RNA polymerase that synthesizes short RNA primers on the template strand, providing a 3-prime OH group for DNA polymerase to begin synthesis.

The 3-prime to 5-prime exonuclease activity of DNA polymerase that detects and removes mismatched nucleotides immediately after incorporation.

The Y-shaped region where the two parental DNA strands are separated and new strands are being synthesized.

The mode of DNA replication in which each daughter molecule contains one original strand and one newly synthesized strand.

Proteins that bind to and stabilize single-stranded DNA at the replication fork, preventing re-annealing and degradation.

A reverse transcriptase enzyme that extends telomeres using its own RNA template, counteracting chromosome shortening.

Repetitive non-coding DNA sequences at chromosome ends that protect against degradation and shorten with each replication cycle.

An enzyme that relieves supercoiling tension ahead of the replication fork by cutting, rotating, and resealing the DNA strands.