The DNA Timeline }

Remember back in the previous module, DNA must replicate before cell reproduction. This is done before mitosis or meiosis takes place. In eukaryote cells, this process takes place in the nucleus. For prokaryotes, this process takes place in the cytoplasm.

DNA REPLICATION

DNA replication is the process of duplicating the DNA molecule. This would happen in the eukaryotic cell's nucleus before the cell divides, whether by mitosis or meiosis. Prokaryotes replicate their DNA in the cytoplasm. Recall that, for eukaryotes, replication occurs during the S phase of Interphase.

Preview the process of DNA replication by watching the following presentation.

Preview the process of DNA replication by watching the following short video.

Pay close attention to how the DNA is copied. Do the two strands of DNA remain attached or break apart to create a copy?

DNA Timeline Challenge and Before You Go

Practice Time! Use the knowledge you learned from the lesson to complete the practice activities below.

Before You Go You Need To Know

The following key points are from the explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

Where in the cell cycle does DNA Replication take place?
- Interphase
What are the base pair rules for DNA?
- Adenine (A) pairs up with Thymine (T); Cytosine (C) pairs up with Guanine (G).
What are the steps of DNA Replication?
- DNA unzips using the helicase enzyme.
- DNA polymerase enzyme attaches the complimentary nucleotide.
- Ligase enzyme connects the sugars and phosphates along the backbone.
- Mistakes are checked and fixed using the nuclease enzyme.
- Each new strand now consists of one parent and one daughter strand.

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