Bacteria Transformation Pre-Lab

Question 1

What is genetic transformation?

Answer 1

A host organism takes in foreign DNA and expresses the foreign gene

Question 2

Ampicillin

Answer 2

A synthetic form of penicillin used chiefly to treat urinary and respiratory infections

Question 3

Luria Broth (LB agar)

Answer 3

A subtype of nutrient agar that may be used for routine cultivation or not particularly fastidious organisms, doesn’t preferentially grow one type of bacteria over another

Question 4

Bacterial colony

Answer 4

Millions of individual bacterial cells in a small area on the agar

Question 5

E. coli

Answer 5

Escherichia coli; most common bacteria in human gut, reproduces rapidly, has no true nucleus, all DNA found in single chromosome, contains small plasmids

Question 6

Plasmids

Answer 6

Circular pieces of DNA that exist outside the main bacterial chromosome and carry their own functions, used to introduce foreign bacteria to cells

Question 7

ampR

Answer 7

The gene in some plasmids that confers resistance to the antibiotic ampicillin

Question 8

+ampR

Answer 8

Cells that contain the ampR plasmid that can survive and form colonies on LB agar supplemented with ampicillin

Question 9

-ampR

Answer 9

Cells lacking the ampR plasmid and thus sensitive (killed by) the ampicillin antibiotic

Question 10

Competent cells

Answer 10

Cells that incorporate foreign DNA if their cell walls are altered so that DNA can pass through more easily; cells are made competent through calcium chloride and heat shock

Question 11

Log phase of bacterial growth

Answer 11

Period of rapid cell division, following their lag phase (slow colony growth due to small number of dividing cells), length of period depends on temperature of incubation

Question 12

What are five sterile techniques to practice?

Answer 12

1. Wash hands and works surface before beginning.
2. Keep lid of petri dish on it or over it at all times.
3. Open all sterile tools carefully.
4. Keep hair pulled back and use goggles in presence of flame.
5. Wash hands with soap and hot water before leaving lab.

Question 13

What are four unsafe practices to avoid?

Answer 13

1. Never have food on work surface.
2. Never lay lid of petri dish or culture tube on lab bench.
3. Never touch end of a tool that touches bacteria.
4. Never throw biohazard materials in regular trash.

Question 14

What are four unsafe practices to avoid?

Answer 14

1. Never have food on work surface.
2. Never lay lid of petri dish or culture tube on lab bench.
3. Never touch end of a tool that touches bacteria.
4. Never throw biohazard materials in regular trash.

Question 15

What are the 6 stages of transformation?

Answer 15

1. -ampR cells are transferred to cold CaCl2 solution
2. ampR plasmids added to experimental cells only
3. Cells are heat-shocked at 42 degrees C
4. Treated cells are spread on agar containing ampicillin
5. Cells are incubated for 24 hours.
6. Only colonies of E. coli that have been transformed with ampR gene will grow.