BIOLOGY II

CAZARES MENDEZ ADRIANAROSALES J IMENEZ PAMELA

ROSAS HERRERA BENNE ERANDIVILLANUEVA AGUILAR JORGE

ALBERTO

DNA Replication

Background Information.

Watson and Crick discovered DNA’s structure: the double helix.

This structure explained how DNA was copied or replicated.

Each strand of the double helix can reconstruct another strand by the mechanism of base pairing.

These strands are said to be complementary.

Key Concept

During DNA Replication, the DNA molecule separates into two strands. Then, following the rules of base pairing, it produces two

complementary strands. Each strand of the double helix of DNA serves as a template, or

model for the new stand.

DNA replication takes place before cell division. This ensures that each new cell has a complete set of DNA.

In prokaryotes, it begins at a single point in a chromosome and proceeds often in two directions until the entire chromosome is replicated.

In eukaryotes, it occurs at hundreds of places, proceeds in both directions too until each chromosome is copied.

These areas in which separation and replication occur are called: replication forks.

Process of DNA replication

Who makes DNA replication possible

DNA replication is carried out by a series of enzymes. These enzymes unzip a molecule of DNA.

Unzipping occurs when hydrogen bonds between the base pairs are broken and two strands of the molecule unwind.

The principal enzyme involved in this process is called DNA polymerase.

It joins individual nucleotides to produce a DNA molecule (polymer). DNA polymerase also “proofreads” each new

DNA strand to make sure it is a perfect copy of the original strand.

JOKES How do you eat a DNA spaghetti?-With a replication fork (you can also use your zinc fingers...)