Laboratory Exercise 7 Pure Culture Techniques

Question 1

Originate from many strains of bacteria
Colonies have different size, shape, color

Answer 1

Mixed Culture

Question 2

A culture in which only one strain or clone is present
Colonies look the same

Answer 2

Pure culture

Question 3

Importance of Pure Culture Tehniques

Answer 3

Samples from the envi are not pure - mixture of multiple types of bacteria
A pure culture of a single microorganism is required for lab identification and susceptibility technqiues
There are methods that allow one to separate or isolate a single bacterial colony

Question 4

Two most commonly used techniques of getting a pure culture from mixed bacterial population

Answer 4

Streak Plate - Radiant or Quadrant
Pour Plate

Question 5

This method is routinely employed for the isolation of bacteria in pure culture from clinical specimens

Answer 5

Quadrant Streak Plate Method

Question 6

Spread plate vs pour plate
Colonies

Answer 6

Spread plate - surface colonies
Pour plate - surface and subsurface colonies

Question 7

Staphylococcus aureus vs Bacillus cereus

Answer 7

SA - golden yelllow, circular, small, entire, convex, + cocci
B. cereus - white, irregular, medium, undulate, crateriform, + bacilli

Question 8

This technique consists of cooling melted agar (42-45 degrees C) and inoculating the agar medium with an inoculum prior to pouring it into sterile Petri dish. This was developed by bacteriologist _

Answer 8

Pour Plate Method by Robert Koch