Page 171 - MNU microbiology theoritical 2025

General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025

DNA Replication

• DNA replication is an important process that occurs during cell division. It is

also known as semi-conservative replication, during which DNA makes a

copy of itself.

• It is a biological polymerization, which proceeds in the sequence of initiation,

elongation, and termination.

• It is an enzyme-catalyzed reaction. DNA polymerase is the main enzyme in

the replication process.

DNA Replication Steps

1- Initiation

• Replication begins with the origins of replication (bubbles).

• Prokaryotes (bacteria) have a single

bubble, while eukaryotes have many

bubbles.

• A replication fork is created catalyzed

by the helicase enzyme, which unzips the

DNA strand.

Single-Strand Binding Proteins: attach and

keep the 2 DNA strands separated

• Topoisomerase relaxes the supercoiled DNA

General Microbiology & Immunology (PM 401) theoretical handbook Page 160