1. DNA Replication….some facts….. 1.Definition: Process by which DNA copies itself 2.Happens when chromosomes copy themselves before mitosis and meiosis (the processes when cells divide) 3.Semi-conservative replication: Each new piece of DNA is made up of 1 old strand and 1 new strand 4.Replication begins on both strands of the molecule at the same time. http://www.biologie.uni-hamburg.de/b-online/library/bio201/trinity.gif

2. DNA Replication- cont’d 5. Occurs in the nucleus of the cell 6.The end product of DNA Replication is 2 identical strands of DNA. 7. During cell division, each cell gets 1 strand of DNA. 8.In humans, about 50 nucleotides are added every second to a new strand of DNA! http://www.biologie.uni-hamburg.de/b-online/library/bio201/trinity.gif

3. DNA Replication http://www.coolschool.ca/lor/BI12/unit5/U05L02/DNA%20replication.gif animation

4. DNA Replication – The Steps 1. DNA is unzipped (opened) by helicase at numerous places along the strand, creating replication bubbles. 2. Complimentary nucleotides (nitrogen bases, sugar & phosphate) bond to the bases on the original 2 pieces of DNA strands. 3. These nucleotides were free floating in the nucleus of the cell. 4.An enzyme called DNA polymerase bonds the nucleotides together to form these new strands.

5. DNA Replication