Term
| What is the cell cycle like for bacteria? |
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Definition
-Similar to eukaryotes, but without a G2 phase
-Goes;
C phase (DNA replication); 40min
D phase (division); 20min
G1
...C etc. |
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Term
| What is the difference between slow and fast growing bac? |
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Definition
-Slow only replicated DNA once during the cell cycle
-Fast can replicate continuously so that cycles overlap |
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Term
| Go through the steps for chromosome replication? |
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Definition
-*DNA-A protein binds to *OriC region
-*DNA-B (helicase) starts the unwinding
-SSBPs bind the loose DNA
-Primase/primosome makes the RNA primer
-**DNA polymerase III** (one per fork) starts synthesis
-Topoisomerase (*gyrase) is needed to relieve winding |
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Term
| What are the DNA polymerases and functions? Which DNA Pols have 3-->5, and which have 5-->3 exonuclease activity? |
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Definition
-DNA Pol I; replaces primers and fills gaps
-DNA Pol II; repair
-DNA Pol III; majority of synthesis
-They all have 3-->5 exonuclease activity (reverse spellcheck)
-Only DNA pol I has 5-->3 exonuclease activity (plucks them out while it puts them in) |
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Term
| What is needed for termination of replication? |
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Definition
-Require the **Tus protein which binds DNA and interferes with the helicase protein (no unwinding)
-T1 gets clockwise fork, while T2 gets counterclockwise
-The way it works is that a fork can pass through in one direction, but not the other; to prevent ripping apart and replication of the newly made DNA |
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Term
| Which way are bacterial chromosomes supercoiled and what does that mean? What does it? |
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Definition
-Negatively supercoiled; underwound (twisted in opposite direction as DNA helix)
-*DNA gyrase accomplishes the coiling (uses energy to introduce, and passive to relax) |
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Term
| What inhibits DNA Gyrase? What are some examples? |
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Definition
The quinolones;
-Ciprofloxacin, norfloxacin, novobiocin, coumermycin, malidixic acid |
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Term
| What are inhibitors of chromosome replication (7)? |
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Definition
1. Actinomycin D
2. Proflavine
3. Ethidium bromide
4. Mitomycins
5. Metronidazole
6. Nitrofurans
7. DNA gyrase inhibitors (quinolones) |
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Term
| How do bac terminate transcription? |
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Definition
| -Rho factor or a stem and loop structure forms (from series of U's in the transcript) |
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Term
| What are the strands of DNA called? |
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Definition
-Transcript and coding strand
-The coding strand is basically the same as the one transcribed (save Us instead of Ts) |
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Term
| What are some transcription inhibitors (4)? |
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Definition
1. Rifampin
2. Streptovaricin
3. Streptolydigin
4. Actinomycin D (trans and rep?) |
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Term
| What does the Shine Dalgarno sequence bind? |
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Definition
-To the 16S rRNA in the 30S subunit
-Puts AUG in the A slot |
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