LAB week 5 #2

Pure culture

Contains only a single kind of an organism

Contaminated culture

Contains a desired organism but also unwanted organisms

What are two commonly used isolation procedures?

Streak plate and pour plate

Colony

One individual cell divides, and all cells in the colony are assumed to be the identical progeny of the original cell.

Which isolation procedure is most often used by microbiologists to obtain pure cultures?

Streak plate method

What are the different procedures for producing a streak plate?

Quadrant streak (A + B) and radiant streak

What is the most popular and most utilized streak plate method?

Quadrant streak

Which method of isolation separates bacteria by diluting a loopful of organisms across a series of three tubes of liquified nutrient agar?

Pour plate

What is an advantage of using pour plate over streak plate?

It requires less skill

What is an advantage of using streak plate over pour plate?

It requires less media, tubes, and plates

In pour plate method, where will colonies grow?

On the surface and within the agar itself

You should always flame the loop before streaking the loopful of organisms into the next quadrant in quadrant streak. True/false

True

Loops should be flamed before entering a culture tube to prevent contamination of the culture. True/false

True

What temperature should the agar be cooled to before inoculating with bacteria in pour plate?

50 degrees Celsius

What color should S. marcescens be?

Red

M. luteus colonies will be what color?

Yellow/cream

Which of the two bacteria are gram-negative short rods?

S. marcescens

How can you verify the purity of your colonies?

Gram-stained smears