DNA Replication Lecture Notes

Vocabulary flashcards covering the purpose, enzymes, and sequential steps of DNA replication, as well as its role in mitosis and meiosis.

DNA Replication

The process carried out by a series of enzymes by which DNA is duplicated before a cell divides, ensuring every new cell receives a complete copy of the genetic code.

Mitosis

Cell division in which new body cells are produced for growth and repair, preceded by DNA replication.

Meiosis

Cell division that produces gametes (sex cells = sperm or egg), before whose first division DNA replicates so each gamete receives a copy of genetic material present in body cells.

Gametes

Sex cells (sperm or egg) that each receive a copy of the genetic material present in the body cells during meiosis.

Replication Step 1

An enzyme in the nucleus unwinds and unzips the two strands of the DNA double helix, breaking the weak hydrogen bonds between two bases and exposing them.

Replication Step 2

Complementary base pairing of free-floating DNA nucleotides occurs with the exposed bases of the unzipped original DNA strand ($A$ to $T$; $C$ to $G$).

Replication Step 3

An enzyme joins the new DNA nucleotides together by forming sugar-phosphate bonds, establishing the new strand's backbone.

Complementary Base Pairing

Specific base pairing joined by hydrogen bonding where adenine pairs with thymine ($A$ with $T$) and cytosine pairs with guanine ($C$ with $G$).

Parental Strand

An original DNA strand that separates during replication and serves as a template determining the order of nucleotides along a new complementary strand.

Daughter DNA Molecule

A newly formed DNA molecule resulting from replication that consists of one parental strand and one new strand.

Sugar-Phosphate Backbone

The structural chain created when sugar-phosphate bonds form between adjacent nucleotides in a newly synthesized DNA strand.