DNA

2 DNA Functions Stores genetic information to build and maintain a living organism Copies itself

3 James Watson & Francis Creek 1953 Determined the three- dimensional structure of DNA One of the greatest discoveries in the history of science Nobel prize in 1962

4 DNA Made of repeating units called nucleotides Each nucleotide made of a sugar named deoxyribose, a phosphate and a base

5 DNA Nucleotide Deoxyribose Phosphate Base =

6 Nucleotides Form a Double Strand Deoxyribose Phosphate Base

7 DNA Molecule is Double Stranded

8 Base Pairing Rule Adenine pairs with Thymine Guanine pairs with Cytosine

9 DNA Total length of DNA in each cell is about 6 feet Wraps around proteins called histones Over 3 billion nucleotide pairs in human DNA!

10 DNA Replication DNA strands separate DNA nucleotides attach to each strand

11 Each new DNA molecule will be an exact copy of the original

12 First, DNA strands separate

13 Second, an RNA attaches to DNA strand DNA cannot start replication on its own

14 Third, DNA nucleotides are attached to DNA strand

15 Fourth and final, the RNA is removed

16 DNA Errors Replication is not 100% accurate –Errors occur when copying DNA DNA damaged –Ultraviolet light –X-rays –Cigarette smoke –Nitrates (smoked meat) –Pesticides & Herbicides

17 The End