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DNA ..

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Presentation on theme: "DNA .."— Presentation transcript:

1 DNA .

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3 Griffith exp. Hershey and Chase exp.

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5 DNA Deoxyribonucleic acid: DNA two stranded double helix
Purines: adenine and guanine Pyrimidines: thymine and cytosine Bonding: A-T (double bond) and C-G (triple bond) Nucleotide= base-sugar-phosphate 5’ ’ DNA sequence is read in a 5’ to 3’ 3’ ’

6 DNA Replication: unzipping DNA double helix
Replication: the process by which DNA is copied during the cell cycle (s stage) Enzymes and other proteins carry out the work of replication Once the strands are separated: free nucleotides within the nucleus can then be paired up with the separated strand in correct sequence DNA Polymerase: enzyme that bonds the new nucleotides together Also proofreads and corrects any base pairing errors

7 Replication Helicase: enzyme that unzips the DNA double helix into a Y shaped replication fork Leading strand and lagging strand: each strand becomes a template for a new complimentary strand Semiconservative replication: New DNA consists of one old template strand and one new complimentary strand

8 Replication Primase: starts the complimentary strand with short segments called RNA primers DNA polymerase bonds to the primers. This begins elongation: DNA nucleotides added to the complimentary strand Leading strand assembles continuously 5’ to 3’ Lagging strand assembles in short pieces called Okazaki fragments DNA Ligase: joins the fragments together

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