Lecture 11 Genome Replication and Expression Flashcards
Describe the shape of Prokaryotic DNA
- Usually circular, closed, supercoiled molecule
What is the nucleoid?
Where bacteria pack their DNA into loops or domains
What shape is Eukaryotic DNA
- Linear
What are histones?
Proteins in which Eukaryotes wrap there DNA, all together it is called the nucleosome
What is Semiconservative
- strands separate
- each serves as a template for synthesis of a new strand
Describe DNA replication in Prokaryotes
- bidirectional
- single ori (origin of replication)
- 2 forks
- opposite directions
Look over figures 13.12 and DNA replication
Look over figures 13.12 and DNA replication
Look over the Table 13.1 for E.coli replication machines and their functions
Look over the Table 13.1 for E.coli replication machines and their functions
Transcription - Bacteria
- RNA from DNA
- RNA Polymerase = core + sigma factors
- Antibiotic rifampin targets bacteria RNA polymerase
What are sigma factors
Proteins, direct core to promoters
ex.) sigma 70, sigma S
Look over Figure Describing Transcription in Bacteria
Look over Figure Describing Transcription in Bacteria
What is a Terminator?
- DNA sequence
- encodes RNA stem loop structure
- causes RNA Pol release
- DNA sequence
- Causes RNA pol to pause
- Protein Rho binds RNA
- Moves towards RNA pol and causes release.
What is Histidine Kinase?
Bacteria use two-component signal transduction systems to control gene transcription in response to their environments
What does the EnvZ/OmpR system sense and control?
Read pgs 334-335
Transcription in Eukarya
- In nucleus, uses 3 RNA Polymerases
- Transcription factors ( no stigmas)
- TATA box - promoter element
- RNA splicing to remove introns
