AP Bio DNA Enzyme Vocab Quiz

Topoisomerase

An enzyme that relieves the stress caused by the unzipping of the DNA by helicase by cutting, swiveling, and rejoining the sugar backbone

Helicase

An enzyme that unzips the parent DNA strand by breaking the hydrogen bonds between the base pairs

Primase

An enzyme that adds RNA primer

DNA Polymerase III

Enzyme that catalyzes the elongation of the new DNA strand, builds the complement strand according to whatever the original strand bases are

Leading strand

Where DNA polymerase follows helicase and builds complement strand as one long segment from 5’ to 3’

Lagging strand

Built in many segments since it is going in the opposite direction as helicase

Okazaki fragments

Short segments of new DNA on the lagging strand

DNA ligase

Enzyme that joins the gaps in the sugar backbone that DNA polymerase I left

DNA Polymerase I

Removes the primer and replaces it with DNA

Nuclease

Enzyme that cuts out damaged DNA

Telomerase

Maintains the telomeres (ends of chromosomes) in gametes

Single-strand binding protein

Protein that attaches to one strand and keeps the unzipped strands from resealing