1. Exam #1 W 9/26 at 7-8:30pm in UTC 2.102A
Review T 9/25 at 5pm in WRW 102 and in class 9/26

2. The relationship between DNA and genes
Fig 8.3
The relationship between DNA and genes
a gene
promoter
coding region
terminator
non-gene
DNA

3. Promoter sequences in E. coli
Fig 8.7

4. Transcription initiation in prokaryotes: sigma factor binds to the -35 and -10 regions and then the RNA polymerase subunits bind and begin transcription
Fig 8.8

5. Transcription Elongation
Fig 8.9
Transcription Elongation

6. Termination of Transcription
Fig 8.9

7. Eukaryotic promoters are more diverse and more complex

8. Transcription initiation in eukaryotes
Fig 8.12
Transcription initiation in eukaryotes

9. Some genes code for RNA (tRNA, rRNA, etc) mRNA is used to code for proteins
RNA synthesis
Protein

10. rRNA is transcribed by RNA polymerase I

11. tRNA is transcribed by RNA polymerase III

12. mRNA is transcribed by RNA polymerase II

13. mRNA is processed during transcription and before it leaves the nucleus.
(transcribed from DNA)

14. Addition of the 5’ cap, a modified guanine
Fig 8.13

15. Addition of the 3’ poly-A tail
Fig 8.13
After the RNA sequence AAUAAA enzymes cut the mRNA and add 150 to 200 A’s

16. DNA Composition: In humans:
Each cell contains ~6 billion base pairs of DNA.
This DNA is ~2 meters long and 2 nm wide.
~3% directly codes for amino acids
~10% is genes
In a single human cell only about 5-10% of genes are expressed at a time.

17. mRNA is processed during transcription and before it leaves the nucleus.
(transcribed from DNA)

18. Splicing of introns
Fig 8.13

19. Conserved sequences related to intron splicing

20. Splicing an intron: intron removal.
Fig 8.16

21. Splicing an intron: reattach exons.
Fig 8.16

22. Some introns are self-splicing.
Fig 8.18

23. Alternate splicing of introns/exons can lead to different proteins produced from the same gene.

24. Complex patterns of eukaryotic mRNA splicing
(-tropomyosin)
Fig 8.14

25. Fruit fly DSCAM, a neuron guide,
115 exons over 60,000 bp of DNA
20 exons constitutively expressed
95 exons alternatively spliced
For over 38,000 possible unique proteins

26. Size and Number of Genes for Some Sequenced Eukaryotic Genomes

27. Some mRNAs are changed after transcription by guide RNA
RNA editing:
Some mRNAs are changed after transcription by guide RNA