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Description
Flashcards by J yadonknow, updated more than 1 year ago
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Created by J yadonknow
over 6 years ago
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| Question | Answer |
| What is the typical size of an archaeal genome? | 2mBp |
| What is the typical size of an E.coli genome? | 4.6 mBp |
| What is the typical size of a human chromosome? | 100 mBp |
| Why should prokaryotes technically just accumulate bad mutations? | Haploid and reproduce asexually by binary fission, no influx of "fresh" genes |
| Plasmid cohabitation | May be exclusive or exist in multiple species co-existing plasmids = compatible can't co-exist = incompatible |
| What are the 3 basic GI types of plasmids? | 1. Sequences for replication + segregation of plasmids during replication 2. Useful extra genes to confer auxiliary metabolic pathways to host cell. 3. Tra genes to allow transfer of plasmid copy to new cells. |
| What sequences are responsible for rep+segregation? Name 2 examples. (3) | Origin of replication genes OriP in plasmids OriC in chromosomes |
| What methods may they employ to do so? | Recruit host cell enzymes to replicate the plasmid DNA May have systems that allow plasmid to stick to chromosome and "hitch-hike" during cell division. |
| Name 3 functions that additional genes may confer. | i. Carb utilisation ii. Nitrogen fixation iii. Organic compound degradation. |
| What factors in host cell infections are important? Name 2 examples. | Virulence factors like Haemolysis Enterotoxin |
| What can be seen on a typical agar jar with bacteria of differing AB sensitivity? | No resistance = zone of cell death Resistant bacteria grow right next to AB Lawn of bacteria growing on agar |
| What plasmid is responsible for the dangerous staphylococcus strains from hospitals? | pGO1 resistance (R) plasmid |
| What type of plasmid is this? | conjugative R plasmid with trs genes |
| What does it confer resistance to? | 4' ammonium compounds aminoglycosides bleomycin trimethoprim |
| What gene encodes transposases? | Tnp |
| What are the simplest known transposable elements? | called insertion sequences, smallest one is IS1 |
| What do tra genes do? | Allow plasmid conjugation between prokaryotes |
| Outline the process by which a donor cell donates its plasmid to a recipient (7) | 1. tra genes of F+ plasmid encode pilins to form a pilus 2. F+ strain recognises F- and attaches via pilli 3. Pillus retracts, pore forms between cells 4. ssDNA produced from OriT (OG of transfer) 5. ss pulled off like rolling circle 6. Rolling circle replication = sigma replication 7. Recipient F- synthesises comp. DNA to form dsDNA. |
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