conjugation 2
Terms
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- What is conjugation?
-
1)Direct transfer of DNA btw two bacteria
2)Conjugation pilus
3)Replication of DNA being transfered(Rolling Circle)
4)Generally btw "related species" and within family members. - Donor cell is the ??
- Male
- Recipient cell is the ??
- Female
- What is the Episome?
- It is the DNA transfered, it is like a large plamid.
- Where is the information for Pilus formation and DNA replication?
- On the plasmid.
- What are the gene functions carried on plasmids?
-
1)Antibiotic resistance genes(called the 'R' plasmid)
2)virulence Genes(Virulence plasmids)
3)Antibacterial Genes-for competition(Colicins "Col Plasmids" - What is an Hfr cell?
- A cell in which the episome recombine into the chromosome.
- Can Hfr cells be donors?
- Yes
- What is a F' cell?
- A cell in which the chromosom was integrated into the episome. Also may function as donors.
- What is transformation?
- Uptake of naked DNA.
- What are two examples of species that are good at natural transformation?
-
1)Neisseria gonorrhoae
2)Streotococcus sp. - What is competence?
- relative ability to take up DNA
- What does competence do?
-
1)facilitate DNA uptake by converting DsDNA to ssDNA
2)manifest by proteins associated with the cell envelope(G+ wall G- inner membrane)
3)DNA is taken up generally as a ss molecle.
4)Once inside the host, the DNA can integrate into the genome. - Because this process occurs btw closely related species ___ ___ can occur.
- homologous recombination
- What is a artificial competence enhancement and what is it good for?
- Calcium Chloride. It is good for small plasmid transformation.
- What is transduction?
-
1)Virus mediated DNA transfer
2)bacterial viruses(Bacteriophage) - Studying bacterial viruses allowed for what?
- Major contributions to be made in basic genetics and gene regulation.
- What are the two possiblitites that may result from infection?
- Lytic Cycle or the lysogenic cycle
- What is the lytic cycle?
-
1)Viral DNA replication(host machinery)
2)Utilization of host protein synthesis machinery.
3)Packaging of viral nucelic acids into viral heads.
4)Final assembly.
5)Lysis and release from host. - What is the lysogenic cylce?
-
1)Viral DNA intergrates into host DNA("ATT" sequences)
2)Viral DNA is copied along with host
3)Transferred to offspring with chromosome - What can trigger the lysogenic cyle to enter the lytic cycle?
-
1)UV radiation
2)Chemical(DNA damaging agents) stress
3)heat - Occasionally host(bacterial) DNA that is degraded may ??
- get packaged into a viral head.
- Upon a second infection the first hosts DNA is transferred into the ??
- second host.
- Sometimes viruses integrate their DNA into ??
- host chromosome at specific sites
- Upon starting a lytic cycle viral DNA excision may accidentally take some ??
- host DNA with it. This host DNA and viral DNA may now be transferred to a second host.
- Why is the phage packaged with both viral and bacterial DNA called a speciallized transducing phage?
- Because only DNA sequences that flank the integrated viral DNA may be transferred to the new host.