DNA Replication DNA Replication is the process by
DNA Replication
DNA Replication… • is the process by which DNA is copied • takes place during S phase • is required for the formation of two identical daughter cells in mitosis M S Enough for one cell Enough to share
DNA Replication… • is semi-conservative: § Each half of a DNA “ladder” serves as a template § Each new DNA molecule has one side of original DNA (conserved) and one side that is Original DNA (conserved) brand new Original DNA New DNA
DNA Replication… • relies on enzymes: § Helicase unzips (splits apart) the two sides of a DNA molecule by breaking hydrogen bonds between base pairs § DNA polymerase adds new nucleotides to the templates following the rules of base pairing • occurs at the replication fork (area of unzipping)
STEP ONE • The DNA double helix uncurls to form a ladder shape. • At this point, there are two complementary strands • It prepares for replication
STEP TWO • The two DNA strands are separated by the breaking of the hydrogen bonds by helicase • This forms a replication “fork” • Add clip of replication
STEP THREE • Polymerase attaches free-floating nucleotides into correct base pairs • Hydrogen bonds re-form
STEP FOUR • Two identical daughter strands are formed! • Base pairs consist of one original strand its complement
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