DNA REPLICATION An Overview of the Process Replication

DNA REPLICATION An Overview of the Process

Replication Defined… DNA Replication � Prior to dividing, a cell will replicate (or make a copy of) its DNA in the nucleus to ensure that each new daughter cell has a complete set of DNA molecules

When is DNA Replicated? Remember: � The cell cycle consists of a series of steps: Interphase G 1: cell growth S: Chromosome replication/DNA synthesis G 2: organelles essential to division are made M Phase Mitosis Prophase Metaphase Anaphase Telophase Cell Division Cytokinesis

How is DNA Replicated? The long version: � This is when the double helix is separated into 2 separate “template” strands by an enzyme called helicase, so that an enzyme called DNA polymerase can pair free floating bases to the “template” strand forming a new “complimentary” strand, thus duplicating the existing supply of DNA molecules… …whoa…let’s break it down.

How is DNA Separated? The 2 sides of the DNA molecule are separated into 2 separate “strands” by an enzyme called helicase

Key Info: An enzyme called helicase? � Back up: an enzyme is a protein that acts as a biological catalyst � Back up further: a catalyst is a substance that speeds up the rate of a chemical reaction � Put it together: helicase is a substance made of protein that helps the process of DNA replication

How is DNA Separated? As you can see, helicase “unzips” or “unwinds” the double helix of DNA into 2 separate strands by breaking hydrogen bonds between bases You are left with 2 template strands �A template strand is a strand of DNA that you can use to build another matching strand, thus making more DNA replication bubble

How is New DNA Made? With the 2 template strands separated, we can see how new DNA is made: Another enzyme called DNA Polymerase attaches free floating bases to the template strands following the rules of base pairing � (A with T, G with C) Take a look…

How is New DNA Made?

Better Yet…