1. What is DNA? Instructions for making proteins
‘Blueprint’ for who we are
Where is it found?
Found in the nucleus
What does ‘DNA’ stand for?
Deoxyribonucleic Acid

2. The Structure of DNA
Double helix
Structure of DNA: Twisted Ladder

3. Who Discovered DNA’s Structure?
SCANDAL! Read all about it!
Rosalind Franklin, James Watson, Francis Crick, & Maurice Wilkins discovered the shape (double helix) of DNA is 1953.

4. DNA is a polymer of Nucleotides. What are the 3 parts of a nucleotide?
THINK!
DNA is a polymer of Nucleotides.
What are the 3 parts of a nucleotide?

5. Nucleotides
DNA Subunit
3 components
a sugar
a phosphate group
a nitrogen base

7. Nitrogen Bases 4 Types: Adenine Thymine Guanine Cytosine REMEMBER:
At The Golf Course

8. Complementary Base Pairs
Nitrogen bases always pair with the same partner
Hydrogen bonds hold the bases together.
A--T (At--The)
G--C (Golf--Course)

9. THINK! What would the complementary strand be?
A-T-C-C-G-T-T-T-A-C-A-G-G-A
T-A-G-G-C-A-A-A-T-G-T-C-C-T

10. Nucleotides join to form long chain (polymer) Sides of the ladder:
How DNA Strands Form
Nucleotides join to form long chain (polymer)
Sides of the ladder:
Sugar + Phosphate
Rungs of ladder:
Nitrogen bases bond together

11. How is DNA Organized?
Histone proteins act like spools that wind up DNA to keep it organized.

12. During Interphase…
How does DNA exist?
Unwound! (Chromatin)

13. Why Chromatin? What happens during Interphase?
DNA Replicates!
DNA is uncoiled so that enzymes can unzip it.
When it is unzipped, DNA can be duplicated.

14. DNA Replication
Process where DNA is copied
Occurs before mitosis and meiosis (during interphase!)

15. How DNA Duplication Occurs
Step 1: Enzymes unzip the DNA strand T A G C
ENZYME

16. Step 2: Free nucleotides bind to the complementary bases.G C

17. Result: 2 Complete Strands!G C

18. Semiconservative Replication: one of the original strands is present in each new strand of DNA.

19. The Central Dogma
DNA RNA Proteins