DNA Replication Vocabulary

Vocabulary flashcards covering the key enzymes, structures, and processes of DNA replication.

Interphase

The phase in a eukaryotic cell before mitosis or meiosis during which DNA replication occurs.

Helicase

The unzipping enzyme that unwinds double-stranded DNA by breaking through the hydrogen bonds holding the bases together.

DNA Polymerase

The builder enzyme that replicates DNA molecules to build a new strand in the $5'$ to $3'$ direction and possesses proofreading ability.

Primase

The initializer enzyme that synthesizes RNA primers to show DNA polymerase where to start building.

Primer

A short sequence made of RNA that is created by primase so that DNA polymerase knows where to begin replication.

Ligase

The gluer enzyme that seals together gaps between Okazaki fragments on the lagging strand.

Origin

A specific location identified by certain DNA sequences where DNA replication begins and helicase unwinds the double helix.

Single-Stranded Binding (SSB) Proteins

Proteins that bind to separated DNA strands during replication to prevent them from annealing back together.

Topoisomerase

An enzyme that prevents DNA from supercoiling and overwinding ahead of the replication fork.

Supercoiling

The overwinding of DNA that must be controlled during replication so the strands can remain separated for replication enzymes.

Antiparallel

The opposite directional orientation of the two complementary strands in a DNA molecule, where one strand runs $5'$ to $3'$ and the opposite runs $3'$ to $5'$.

Leading Strand

The newly synthesized DNA strand that is built continuously in the $5'$ to $3'$ direction as the replication fork opens.

Lagging Strand

The newly synthesized DNA strand built discontinuously in the $5'$ to $3'$ direction away from the replication fork, requiring repeated RNA primers.

Okazaki Fragments

Short segments of newly synthesized DNA formed discontinuously on the lagging strand during DNA replication.

Semiconservative Replication

The mechanism of DNA replication resulting in two double helix copies, each containing one original template strand and one newly synthesized strand.

Proofreading Ability

The capability of DNA polymerase to identify and correct mismatched bases, preventing errors and incorrectly coded genes.