Excersize 12 - Pure Culture Techniques

Question 0

Properties of agar

Answer 0

Polysaccharide produced by seaweed

Adds no nutrient value

Question 1

Procedure for pouring an agar plate, steps in order

Answer 1

Label the bottom of the sterile Petri dish

Allow tube to cool before pouring

Flame tip of tube

Pour a tube of trypticase soy agar into dish

Gently rotate the plate until it becomes evenly distributed

Question 2

What are the 3 key temperatures for agar?

Answer 2

Melts at 100 C

Solidifies at 40-42 C

Pour temp 50 - 55 C

Question 3

Why is the lid on the plate vented after pouring

Answer 3

To prevent condensation build up

Question 4

Streak plate method steps (in order)

Answer 4

Shake culture tube

Flame loop

Remove cap, flame tube

Remove loopful of organisms

Flame tube, replace cap

Return tube to rack

Streak the plate

Flame loop

Question 5

What is the theory behind quadrant streak

Answer 5

Isolate colonies of bacteria

Question 6

Subculture technique, in order

Answer 6

Poke center of isolated colony

Streak on slant tube

Incubate

Question 7

Subculture

Answer 7

Yellow, white, and red bacteria in each slant

Question 8

What final step is performed on to ensure purity of the bacteria?

Answer 8

Gram stain the bacteria and look at it under microscope

Question 9

Pure culture 3 main phases

Answer 9

Streak agar

Transfer pure cultures to slants

Gram stain, look under microscope