12689417
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 |
| How do chromosomal genes end up in plasmids? | Reciprocal strand exchange at sites of homology between insertion sequences, homo reco. |
| What do transposase enzymes do | Move the gene as a TRANSPOSON |
| How do transposons encourage genetic diversity? | Allow homologous recombination |
| How is this process used during DNA replication repair? | Repairs stalled replication forks by resolving Holliday junctions when they arise |
| What is the name of a plasmid that has been inserted into a genome? | integrated plasmid |
| What is an episomal plasmid? | A plasmid capable of reversible integration into a chromosome |
| How can a prokaryotic plasmid and chromsome exhibit diploid characteristics? (4) | 1. Plasmid picks up Gene1 from chromosome via excision. 2. Conjugation with another cell occurs. 3. Homology with chromosomal allele of Gene1 in recipient (little X). 4. HR can occur, recipient cell essentially becomes diploid for the region of chromosome containing Gene1. |
| How do conjugative plasmids unravel chromosomes? (2) | An integrated OriT will mobilise both the plasmid AND the chromosome It still has tra genes and will encode a pili and try to join to F- cells |
| How does this increase the amount of G. variation? | As the chromosome now becomes fully available for HR. |
| Why does the transfer of whole chromosomes rarely occur? | As the conjugation pili is prone to breakage. |
| What name is given to cells that have integrated conjugative plasmids? | Hfr strains |
| What is Transduction? | Chromosomal DNA movement between cells mediated by a prokaryotic virus. |
| What is general transduction? | Viral mediated GI transfer |
| Outline the steps of a lytic lifecycle. (6) | 1. Attachment 2. Injection of viral nuc. acid. 3. N. acid rep. 4. Viral capsid synth. 5. Viral assembly. 6. Cell lysis + virion release |
| MOA of transduction (3) Eat Pack Sex | 1. Digestion Host Chr DNA with nuclease. 2. Encapsulation Host Chr DNA into capsid and incorporation into viral genome. 3. Undergo HR w/ new host cell at sites of homology, as opposed to lytic infection. |
| What is special transduction? | If host cell is exposed to cell-stress, then Lambda virus will leave, accidentally pack host Chr DNA with it. |
| What is transformation? | Deliberate uptake of external DNA |
| How can you force competence in E. Coli? | Treat w/ 100mM CaCl2 and 15s heatshock. |
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