1 Explain in 25 sentences the function of the ampicillin in

1.) Explain in 2-5 sentences the function of the ampicillin in our LB Broth:

• Include in your answer what specifically the bacteria need to grow in a medium containing Ampicillin.

2.) 37ºC is the optimal temperature for growing E. coli. In 2-4 sentences explain what would happen if we lowered the temperature to 35ºC.

What do you expect would happen? What if you increased then temperature to 40ºC?

3.) During which of the 4 bacterial growth phases (lag, log, stationary or death phase) should we use the bacteria (spin down the bacteria and isolate the R plasmid they contain)? Briefly explain why.

Solution

Que-1.) Explain in 2-5 sentences the function of the ampicillin in our LB Broth:

• Include in your answer what specifically the bacteria need to grow in a medium containing Ampicillin.

Ampicillin is useful to isolate selective stains which have antibiotic resistance genes from the LB broth. The potential recombinant colonies can be harvested with a stably cloned foreign DNA fragment in the plasmid by subjecting them inoculation in 5 ml of LB broth containing LB broth followed by incubating at 37°C with shaking at 200 rotations per minute. So that ampicillin useful specifically to isolate transformants which have taken up plasmid DNA that has bla gene (amp-antibiotic resistance genes)

QUes-2.) 37ºC is the optimal temperature for growing E. coli. In 2-4 sentences explain what would happen if we lowered the temperature to 35ºC. What do you expect would happen? What if you increased then temperature to 40ºC?

Membrane of the prokaryote is stronger and prevents melting at high temperatures due low membrane. The optimum incubation temperature for the bacterial growth is 37 degrees where inner cell conents and cell wall of bacteria can withstand growing temperature and membrane fluidity will be damaged at lower temperature finally cause leakage of internal cell contents.

High temperature of incubation to 40degrees is leading to lowering transition temperature and causes high membrane fluidity finally cell wall breakage & cell death