DNA Replication This is when DNA replication happens! (part of interphase)

There are many origins of replication in eukaryotic chromosomes. 1) Enzymes unzip the double helix from multiple locations.

2) Free-floating nucleotides form hydrogen bonds with the template strand. nucleotide The DNA molecule unzips in both directions.

3) DNA polymerase enzymes bond the nucleotides together to form the double helix. (forming covalent bonds between nucleotides in the new strand and the outside deoxyribose sugars and phosphates). DNA polymerase new strand nucleotide

4) Two new identical molecules of DNA are formed, each with an original strand and a newly formed strand. ***DNA Replication is “semiconservative” because 1 strand is conserved in the process. original strand new strand Two molecules of DNA

Replication Facts: In human cells, 50 nucleotides are added every second to a new strand of DNA. The replication process takes about 8 hours in human cells. DNA polymerase has a built in “proof-reading” function to correct errors. Errors are limited to 1 error/per billion nucleotides!