DNA Replication

Why is DNA Replication needed? When cells are dividing… During Interphase of Mitosis & Meiosis DNA must be copied so that each new cell has a full copy of the DNA Either to GROW or make gametes or replace dead cells

Starting DNA Replication The two strands of DNA are unzipped by an enzyme called HELICASE The hydrogen bonds between the nitrogen bases are broken Creates a replication bubble Each strand is now called a “parent strand”

DNA Replication Each “parent strand” is used as a template to make the strand they are missing This is called the complementary daughter strand of DNA To make the daughter strand complementary nucleotides are added to the bases of the parent strand The enzyme DNA polymerase does this

DNA Replication Once the bases are paired the sugar & phosphate groups are linked together The bases are “proof read” We now have 2 IDENTICAL copies of DNA!!

Semi-Conservative Replication Because 1 parents strand is used to make the daughter strand DNA replication is called semi-conservative…1 parent strand is conserved and joins the newly synthesized complementary strand to form the new double helix!