1. DNA
The Molecule of Life

2. What is DNA? DeoxyriboNucleic Acid Chargraff
A=T, G=C
James Watson and Francis Crick
Model of DNA
Double stranded structure
Bases inside

3. What is DNA Made of? Deoxyribose sugar Phosphate Base Purine
A, G
Pyrimidine
T, C

4. What are the Structures of the bases?
Purines
Adenine
Guanine

5. What are the structures of the bases?
Pyrimidines
Thymine
Cytosine

6. Base pairing: how it works
Hydrogen Bonding between bases:
A-T Bonding
2 hydrogen bonds
G-C Bonding
3 hydrogen bonds
Donor and Acceptor

7. A View of base pairing
A:T

8. A View of Base Pairing
G:C

9. What is important about base pairs?
Can predict sequence of one strand based on the sequence of the other.
Replication and Transcription
Repair of damaged DNA

10. Linking it all together:
A, G, C or T
Forms sugar Phosphate Backbone
What makes DNA Different from RNA?

11. Replication: Why? Where? When? What? How?
When cells replicate, each new cell needs it’s own copy of DNA.
Where?
Nucleus in Eukaryotes.
Cytosol in Prokaryotes
When?
S phase of cell cycle
What?
Many proteins: major is DNA Polymerase
How?

12. Replication How? DNA Replication Animation 5’3’ directionality
Starts with RNA primer
Leading Strand
Lagging Strand
Okasaki Fragments
Sequence determined by basepairing
DNA Replication Animation

13. Transcription DNA RNA What is the difference between DNA and RNA?
Ribose Sugar
Uracil not thymine

14. Transcription Where? What? When? Why? How? Nucleus in Eukaryotes
Cytosol in Prokaryotes
What?
RNA Polymerase plus some minor proteins
When?
When RNA is needed
Why?
RNA’s serve many important functions in cells
How?

15. Transcription How? RNA Synthesis Animation 5’3’ directionality
Usually only one strand
Uses Base-pairing
Same idea as with DNA replication
RNA Synthesis Animation

16. Translation What? Where? When? Why? How? RNA Protein Cytosol
When proteins are need, after RNA is made
Why?
Proteins are vital for cells
How?

17. Translation How? Translation Animation Ribosomal Subunits Codon
Small subunit
Large subunit
Codon
Triplet code used
tRNA, rRNA, mRNA
Translation Animation

18. The Genetic Code

19. Why is this important? Genetic Engineering Mutations Cloning
Gene Splicing
Mutations
Cloning