DNA Replication

DNA Replication… M S 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 S M 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 brand new Original DNA (conserved) New DNA Original 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 fork

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 and its complement