MBG 3350 FINAL QUESTIONS AND ANSWERS
What are some key properties of E. coli str. K-12? - Answers - - gram negative
- functionally anaerobic
- cannot survive in the small intestine
- easy to grow and manipulate
What does a recA- mutant do? - Answers - High copy number plasmids will not
recombine
What does a endA- mutant do? - Answers - Does not have the endA endonucleases
which increases yield and transmutation efficiency
How is a mutated lacZ used? - Answers - Cannot metabolize lactose on its own, must
be completed with the lacZ-alpha subunit from a plasmid insert
Why would we use hsdA-/hsdS- cells? - Answers - Because those cells facilitate
propagation of unmethylated DNA or RNA products
Why would we use marA-/marB-/mcrr- cells? - Answers - To facilitate cloning of
exogenous animal or plant genomic DNA
What are Dam and Dcm? - Answers - Site specific methylases
What are the three stages of bacterial growth? - Answers - Lag, exponential (log), and
plateau
Define: transformation, transfection, and transduction - Answers - Transformation: the
natural or experimental acquisition of DNA by bacteria
Transfection: the transfer of DNA into animal or plant cells
Transduction: the acquisition of DNA by bacteria, animal, or plant cells by viral infection
What are the steps involved in heat shock? - Answers - Grow cells to the exponential
phase
incubate with circular plasmid
heat shock -- ~42 C for 60s
incubate with selective media
incubate overnight
True or false: E. coli can take up linear plasmid DNA - Answers - False: Circular
How does electroporation work? - Answers - Use high voltage to open pores to
facillitate DNA uptake
- more efficient than heat shock
What are some key properties of E. coli str. K-12? - Answers - - gram negative
- functionally anaerobic
- cannot survive in the small intestine
- easy to grow and manipulate
What does a recA- mutant do? - Answers - High copy number plasmids will not
recombine
What does a endA- mutant do? - Answers - Does not have the endA endonucleases
which increases yield and transmutation efficiency
How is a mutated lacZ used? - Answers - Cannot metabolize lactose on its own, must
be completed with the lacZ-alpha subunit from a plasmid insert
Why would we use hsdA-/hsdS- cells? - Answers - Because those cells facilitate
propagation of unmethylated DNA or RNA products
Why would we use marA-/marB-/mcrr- cells? - Answers - To facilitate cloning of
exogenous animal or plant genomic DNA
What are Dam and Dcm? - Answers - Site specific methylases
What are the three stages of bacterial growth? - Answers - Lag, exponential (log), and
plateau
Define: transformation, transfection, and transduction - Answers - Transformation: the
natural or experimental acquisition of DNA by bacteria
Transfection: the transfer of DNA into animal or plant cells
Transduction: the acquisition of DNA by bacteria, animal, or plant cells by viral infection
What are the steps involved in heat shock? - Answers - Grow cells to the exponential
phase
incubate with circular plasmid
heat shock -- ~42 C for 60s
incubate with selective media
incubate overnight
True or false: E. coli can take up linear plasmid DNA - Answers - False: Circular
How does electroporation work? - Answers - Use high voltage to open pores to
facillitate DNA uptake
- more efficient than heat shock
