Bact 7

Front 1

The following are properties of what?
- extrachromosomal, double stranded, CCC (covalently closed circular, supercoiled DNA
- found in gram + & - bacteria, often has several
- DNA is discreet from the chromosome
-Show little homology to host chromosomal DNA

Back 1

plasmid

Front 2

1. Do plasmids encode essential (necessary for transcription) genes?
2. are they useful then?

Back 2

1. No
2. Yes, b/c they may give selective advantage

Front 3

Plasmid types
1. For mating or conjugation
2. Antibiotic resistance
3. encode determinants required for pathogenesis
4. mediate degradation of toxic compounds

Back 3

1. Fertility F-plasmid
2. Resistance R-plasmid
3. Virulence plasmid
4. Metabolic plasmid

Front 4

Compatible vs incompatible plasmids
1. Type that have different replication & segregation systems
2. Use the same replication and segregation system

Back 4

1. Compatible
2. Incompatible - they can't be distinguished from each other so both can't be maintained

Front 5

1. What is stringent plasmid replication?
2. Relaxed?

Back 5

1. Replicates in synchrony w/ chromosome
2. Replicates independent of chromosome (high copy #/cell

Front 6

There are 2 plasmids in a cell:
1. What happens if they are of different incompatibility groups?
2. What about the same?

Back 6

1. Each plasmid type is retained in progeny
2. Then one or the other plasmid will be eventually lost. Ka curing of one of the plasmids

Front 7

1. What are the 3 methods of bacterial plasmid transmission?

Back 7

1. Conjugation, transduction, transformation

Front 8

1. How does a type II endonuclease work?
2. What is recombinant DNA?

Back 8

1. It binds to and cuts DNA at a specific sequence; cut may be blunt or staggered; modification depends on a separate methylase
2. DNA that is made by joining 2 pieces cut by the same endonuclease (restriction enzyme) that creates sticky ends

Front 9

1. What is the fxn of a shuttle vector?
2. Do plasmids enhance virulence?

Back 9

1. Replicates and expresses genes in 2 different organisms
2. Yes

Front 10

1. What is a Phage (bacteriophage)?
2. What 3 components do most have?

Back 10

1. Bacterial parasits
2. Genome (single or double stranded DNA, circular or linear or linear single stranded RNA)
Capsid
- protein shell, protects nucleic acid
Tail
- protein structure attached to the capsid

Front 11

1. What type of phage is capable of only lytic growth?
2. 6 stages of lytic cycle?

Back 11

1. Virulent
2. Adsorption (via receptors) -> Penetration -> Expression (transcription/translation has early and late, early for replication and transcription, late for assembly) -> Replication (synthesis of new phage genomes) -> assembly -> release (usually by lysis)

Front 12

1. What type of phage is capable of lysogeny?
2. What type of nucleotide does this have?
3. What does the nuclear material do in this case?

Back 12

1. Temperate
2. Only Double stranded DNA
3. Incorporates into the host cell chromosome or as a plasmid making it a prophage

Front 13

1. What is "integrated phage genome" ka?
2. What is "bacterium with (1)?

Back 13

1. Prophage
2. Lysogen

Front 14

1. What is the key differing step between lysogen and lytic growth?

Back 14

1. Induction - disruption of the lysogenic state and initiation of lytic phase

Front 15

In the lysis/lysogeny decision:
1. What happens when cro predominates/
2. What about cl
3. what does cll regulate
4. lysis vs lysogeny is favored under good growth conditions?

Back 15

1. synthesis of cl is prevented and lytic genes are expressed
2. synthesis of lytic genes are inhibited goes into lysogeny
3. cl and cro
4. lysis

Front 16

Lysogenic strains of bacteria cannot be infected with a phage of the same type as the prophage. the cl repressor (expressed by prophage) represses it

Back 16

...

Front 17

Expression of lysogenic genes by prophage can alter host cell phenotype e.g. toxins produced by a certain corynebacterium diptheriae is carried on the phage. without the phage there is no toxin

Back 17

...