1. DNA Structure

2. OBJECTIVES Describe 3 parts of a NUCLEOTIDE Describe a DNA molecule
Demonstrate COMPLIMENTARY base pairing

3. DNA is Genetic Material
DNA stands for: DEOXYRIBONUCLEIC ACID
Controls protein production in cells
Made up of many genes which control traits

4. Why DNA is Important
Passes genetic information from generation to generation
Traits are controlled by DNA
DNA replicates with little error
Can’t live with out DNA because it part of everything in the body

5. DNA structure PO4 DNA is a double Helix
Meaning DNA has two strands. It looks like a twisted ladder
DNA is polymer made up of units called NUCLEOTIDES
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6. DNA Structure
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A molecule of DNA is formed by millions monomers called nucleotides joined together in a long chain
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7. Nucleotide Structure 3 important parts: Phosphate group
Sugar (Deoxyribose)
Nitrogenous base (G,C,A,T)
Phosphate & sugar make up the “backbone”.

8. 4 Nitrogenous Bases
ADENINE
(A)
THYMINE
(T)
CYTOSINE
(C)
GUANINE
(G)

9. 2 PURINES
The PURINES form hydrogen bonds with the PYRIMIDINES

10. PYRIMIDINES
Big name, small structure

11. Base Pairing ADENINE always pairs with THYMINE
Notice the number of hydrogen bonds formed
CYTOSINE always pairs with GUANINE

12. DNA structure
Each strand is COMPLEMENTARY to the other

13. Complementary Strands
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If we know the DNA sequence of one strand, we can predict the DNA sequence of it’s complement C G T C A A G T G G T T C A A C
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14. DNA Structure DNA strands are ANTI-PARALLEL
Phosphates run in different directions

15. What to do next Complete worksheet in class
When done call me over so I can stamp your sheet
Homework: BRING YOUR BOOK TO CLASS!!

16. Replication