Quiz 3

For a Refrigerator, to test the effect of cold you must put it at

4°C

What does Antiseptic do

kills pathogens on living tissue

Antibiotic Sensitivity 1: Swab a nutrient agar plate in 3 directions to cover the plate with bacteria to create

a lawn of bacteria

Cold temperatures inhibit the growth of some microbes but do not always

kill them

Washing removed dead skin and oil, which covers

normal microbiota

More microbiota is transferred to the plates and is viewed as

more growth

No growth in quadrant 6 because there

ethanol had enough time to kill the microbes on the hand

What is Minimal Inhibitory Concentration (MIC)

lowest antibiotic concentration that prevents growth

When listing the antibiotics in the order of effectiveness from

most to least

Cell membranes – semipermeable – water moves across but not

sugar or salt

What is a Hypotonic solution

High solute concentration inside the cell and a low solute concentration outside the cell

Through Salt Sensitivity, the water rushes into

the cell

What is a Hypertonic solution

low solute (dissolved particles) concentration inside the cell and a high solute concentration outside the cell

pH 4 =

acid - high H+ concentration

Boiling (100°C) may not kill

heat resistant spores (endospores)

What is an Autoclave

15 lbs/in2 allows temperature to reach 121°C, which kills spores in 15 min.

What is Coliform

Gram negative, non-spore forming rod, which ferments lactose to produce acid and CO2 gas.

Indicators of fecal contamination are

Coliforms

Lauryl sulfate broth (LSB) comes in both

Selective

Durham tube (detects gas and lactose fermentation)

What is a Most Probable Number (MPN)

estimates the number of coliforms in a water sample