1. Genes and How they Work
Chapter 15

2. The Nature of Genes
Garrod
Beadle and Tatum
Francis Crick

3. Beadle and Tatum Experiment
Used Neurospora crassa
One gene/one polypeptide hypothesis

4. Central Dogma of Molecular Biology
DNA- RNA- Protein
Transcription to translation
Rule breakers?
Retrovirusese
Reverse Transcriptase

5. The Genetic Code Crick and Brenner Codons Spaced or Unspaced?
Frameshift Deletions

6. Nirenberg Deciphered the Code

7. Genetic Code Almost Universal
So where is it not the same?

8. Transcription Template Strand Coding Strand mRNA Initiation Elongation
Termination

9. Translation tRNA Takes place on the ribosome

10. Types of RNA mRNA- make RNA from DNA template rRNA- found in ribosomes
tRNA-adapter molecule between mRNA and AA’s
snRNA’s- involved in the nuclear processing of eukaryotic pre-mRNA
SRP RNA-mediate protein synthesis in eukaryote
Micro-RNA- newly discovered

11. Eukaryotic vs. Prokaryotic Gene Expression
Characteristic
Prokaryotes
Eukaryotes
Introns
No introns
Most genes have introns
Number of genes in mRNA
Several for each mRNA
Only one gene per mRNA
Site of Transcription and Translation
No membrane bound nucleus- t and t are coupled
Transcription in nucleus, outside nucleus for translation
Initiation of Translation
Begins at AUG preceded by special sequence that binds the ribosome
Gegins at AUG preceded by the 5’ methylated GTP cap
Modification of mRNA after transcription
none
Introns are removed, a 5; cap is added; poly A tail is added

12. Videos
Eukaryotes vs prokaryotes
Translation
spliceosome

13. Words to know
Promoter
Terminator
Operon

14. Spliceosome

15. Types of Mutations Point Mutations Chromosomal Mutations
Bases substitution
Missense vs nonsense
Frameshift
Chromosomal Mutations
Deletions
Duplications
Inversions
Translocations

16. Point Mutations

17. Chromosomal Mutations
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