BIO14 exercises 11, 12, 25, and 26
Consist of only one species of microorganisms, needed to characterize and identify microbes
More than one microorganisms growing in the culture
The presence of unwanted microorganism
a loop is used streak the mixed sample many times over the surface. Use an inoculation loop and dip in the same sample then streak it across the petri dish in a zig-zag motion. The theory is that the bacteria will fall off one by one and grow into a colony. This is the most common isolation technique.
Streak plate technique
The antimicrobial drugs with the broadest spectrum of activity are
A small amount of diluted specimen is spread over a surface of a solid medium using a spread rod.
Spread plate technique
Contain various nutrients that allow one to distinguish one bacteria from another by how they metabolize the media with a waste product.
How would you determine whether a colony was a contaminant on a streak plate
A contaminant would be one growing in an area where you did not streak.
What would happen if the plates were incubated a week longer
TNTC - too numerous to count
A month- None will be isolated if a month
Chemicals used on living tissues to decrease the number of microbes
Inhibits nucleic acid synthesis
Is hot oven or incinerators. They denature enzymes, dehydrate microbes, and kills by oxidative effects. Standard application is 170 *C for 2 hours.
Inhibits cell wall synthesis by preventing cross-linking of peptidoglycan
Is 63-degree Celsius for 30 minutes or 72 degrees Celsius for 15 seconds killing pathogenic organism or those that cause spoilage?
If turns yellow then it is _____________________
Cause temporary inhibition to bacterial growth
Is the disk - diffusion technique measuring bacteriostatic or bactericidal activity? Briefly explain.
Measuring bacteriostatic because instead of killing the microorganisms, they inhibit microbial growth.
A substance produced by a microorganism that inhibits the growth of another.
What is the purpose of peptone in the media?
The Peptone is use as a nutrition source of carbon, nitrogen and energy for growth.
What is the purpose of agar in the media
Agar is used to solidify the bacteria in the media
What is the advantage of using Mueller-Hinton Agar
It allows the antimicrobial agent to diffuse freely.
Zone of inhibition
The area around the disc where bacteria does not grow.