Genetics Test Review

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  • Topic: DNA, DNA replication, DNA polymerase
  • Pages : 4 (1109 words )
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  • Published : April 23, 2013
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Genetics Unit Test Review
1. Six Characteristics of DNA:
1) Consists of 4 bases (GCAT)
2) Double helix
3) The bases are joined by h-bonds
4) The outside of DNA consists of sugar-phosphate bonds
5) The DNA is surrounded by protein
6) Consists of two types of bases:
1. Purines A.G
2. Pyramidines C.T
2. Everything Involved with Replications:
DNA Organization:

*
How does DNA replicate?
3 choices were thought of:

Mechanics of DNA Replication:

Leading Chain:
1) DNA Primase – an enzyme that brings the primer to the Replication fork. 2) DNA Primer – a piece of DNA that attaches to the fork to support the incoming nucleotide. 3) DNA polymerase III – brings in the correct nucleotide to the pre-existing base. 4) Single Stranded Binding Protein (SSB) – holds the 2 original DNA strands apart. 5) Helicase – breaks apart the hydrogen bonds ahead of the fork so the DNA can open up. 6) DNA Topoisomerase IV – makes a clean cut of the sugar-phosphates ahead of the fork to relieve stress. Lagging Chain:

1) Goes in the opposite direction of the leading chain and is discontinuous. 2) RNA Primer supports the incoming nucleotides.
3) DNA Polymerase III brings in the correct nucleotide.
4) DNA Polymerase I attaches bases to the gap left by the RNA primer. 5) Ligase then joins this base to the pre-existing sugar-phosphate chains via phosphodiester bonds. 6) DNA Polymerase II then checks the strand for mistakes. 7) The unconnected DNA segments on the Lagging chain are called Okazaki Fragments. 3. Three Parts of Protein Synthesis:

This is where proteins are made from instructions given by the DNA. These instructions are sent through mRNA to the ribosomes in the Cytoplasm. Ribosomes then turn a specific sequence of amino acids into a certain Protein. 1) Formation of A.A. t-RNA Complex (hooking up):

* An enzyme joins together an amino acid with a specific t-RNA. * A bond is formed...
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