Quiz 2 Study Guide Micro Lab

Colony-forming units per ml is the unit of

plate count

microscopic count

electronic enumeration

turbidimetric measurement

plate count

In the process of dark repair, damaged DNA is repaired by:

UV radiation

visible light

the bacterium undergoing sporulation

enzymes that hydrolyze the bonds at the ends of the damaged region of the DNA strands

enzymes that hydrolyze the bonds at the ends of the damaged region of the DNA strands

Which organism must have oxygen to live?

microaerophile

aerobe

anaerobe

aerotolerant

aerob3

Sour cream, yogurt, and citrus fruits with pH about 4 are easily contaminated by mold because:

fungi grow best in alkaline environments

these foods provide anaerobic conditions

fungi favor acidic conditions

these foods are normally kept at cold temperatures

fungi favor acidic conditions

Most bacteria grow best at pH:

7

1

9

5

14

7

In which of these areas would you most likely find thermophiles growing?

compost pile (57°C)

alpine soil (-12-10°C)

humus layer on forest floor (20-40°C)

hot sulfur spring (36.5-37.5°C)

compost pile (57°C)

A mesophile is able to grow:

in the Old Faithful Geyser of Yellowstone National Park

in the intestinal flora of a cow

in Antarctic soils

in the intestinal flora of a cow

Environmental water will tend to flow out of the cell and if the rate is too great the cell will dehydrate in

hypotonic solution

hypertonic solution

isotonic solution

hypertonic solution

Alkalophiles grow best at which of the following pH values.

pH 7

pH 1

pH 5

pH 10

pH 10

Acetobacter is a bacterium which produces acetic acid (vinegar) and

grows optimally around pH 4.0. Based on this observation, which of the

following describe Acetobacter.

fastidious

acidophilic

autotrophic

mesophilic

acidophilic

A psychrophile is able to grow:

as a pathogen growing in living human tissue

in a deceased lizard in Death Valley, California, in August, temperature 55 degrees C.

under the runners of Santa’s sleigh at the North Pole

under the runners of Santa’s sleigh at the North Pole

Below a species’ temperature minimum:

multiplication of the microbes ceases

the microorganisms thrive

multiplication of the microbes ceases

Pseudomonas aeruginosa is a common pathogen that infects the airways

of patients with cystic fibrosis. It does not grow in the absence of oxygen.

The bacterium is probably which of the following?

an aerotolerant

an obligate anaerobe

an obligate aerobe

a facultative anaerobe

an obligate aerobe

Which method will have colonies embedded in the agar:

spread plate

streak plate

pour plate

pour plate

The damage caused by ultraviolet radiation is:

never repaired

cut out and replaced

repaired during transcription

repaired during translation

repaired by DNA replication

cut out and replaced

Water is a solvent. The dissolved materials in it are called

Solutes

Give the formula for determining bacterial counts.

CFU/ml = number of colonies on plate x dilution factor x plating factor

Bacteria that require oxygen to exist are:

obligate anaerobes

indifferents

facultative anaerobes

obligate aerobes

obligate aerobes

Which of the following best describe an organism growing at 94°C.

extreme thermophile

alkalinophile

psychrophile

mesophile

extreme thermophile

Cultures show a minimum growth rate at their optimum growth temperature.

True

False

False

Which of the following pairs is mismatched?

neutrophile - growth at pH 7

alkalinophile - growth at pH 6

acidophile - growth at pH 5

alkalinophile - growth at pH 6

The germicidal effects of ultraviolet light are limited to specific regions of the ultraviolet spectrum.

True

False

True