(Prelims) MicroBio Lab Exam 3

Question 1

Microbes that are introduced into a culture medium to initiate growth

Answer 1

INOCULUM

Question 2

The microbes that grow and multiply in or on a culture medium

Answer 2

CULTURE

Question 3

• Visible growth of microbes on the surface of the medium.
• It is a population of cells arising from a single cell or spore or from a group of
  attached cells.

Answer 3

COLONY

Question 3

The introduction of microbes into culture medium

Answer 3

INOCULATION

Question 4

A colony is often referred as

Answer 4

colony-forming unit (CFU).

Question 5

used in determining bacterial motility.

Answer 5

• Semisolid media

Question 6

a mixture of polysaccharides derived from red algae.

Answer 6

agar,

Question 7

can be used to determine growth patterns
in a liquid medium, and for certain types of
inoculations and metabolic tests. Also the
method of choice for growing large quantities of
bacteria.

Answer 7

Broths

Question 8

are commonly used to generate
stocks of bacteria.

Answer 8

Agar slants

Question 9

are used for several different types of
differential metabolic tests

Answer 9

Deeps

Question 9

can be used to separate mixtures of
bacteria and to observe colony characteristics of
different species of bacteria.

Answer 9

Agar plates

Question 10

prepared from purified
ingredients and therefore its exact composition is known.

Answer 10

CHEMICALLY DEFINED MEDIUM

Question 11

made up of nutrients including extracts from yeasts, meat, or plants, or digests
of proteins from these and other sources.

Answer 11

COMPLEX MEDIA

Question 12

exact chemical composition is unknown

Answer 12

COMPLEX MEDIA

Question 13

Designed to suppress the growth of unwanted bacteria and
encourage the growth of the desired microbes

Answer 13

SELECTIVE MEDIA

Question 14

Media contain ingredients, such as
sodium thioglycolate, that chemically
combine with dissolved oxygen and
deplete the oxygen in the culture
medium

Answer 14

REDUCING MEDIA

Question 15

is one medium used to isolate the typhoid
bacterium, the gram-negative Salmonella typhi from feces

Answer 15

Bismuth sulfite agar

Question 16

which has a pH of 5.6, is used to
isolate fungi that outgrow most bacteria at this pH.

Answer 16

Sabouraud’s dextrose agar,

Question 17

Used to distinguish one group of
organism from another

Answer 17

DIFFERENTIAL MEDIA

Question 18

used
for Enterobacteriaceae members,
contains bile salt that inhibits most
gram-positive bacteria.

Answer 18

MacConkey’s Agar:

Question 18

For organisms with special contents/ nutrients required for their
growth

Answer 18

ENRICHED MEDIA

Question 19

process of rendering a medium or material free of
all forms of life.

Answer 19

STERILIZATION

Question 19

The medium (enrichment medium) for an enrichment culture is
usually what

Answer 19

Liquid

Question 20

kills by oxidation effect.

Answer 20

Dry Heat

Question 21

burning contaminants to ashes. Method utilized in
inoculating loops.

Answer 21

Direct flaming

Question 21

burns contaminants to ashes. Used to sterilize and dispose
contaminated dressings, bags and cups. An effective way of sterilizing and
disposing of contaminated materials and disposable, tissues, or parts of body

Answer 21

Incineration

Question 22

SHARE KO LANG

Answer 22

c. Hot Air Oven- Exposure to

• 160° C for 2 hours
• 171° C for 1 hour
• Used to sterilize glasswares, oil, jellies and powders
• Kill all microorganisms including sporeformers

Question 23

coagulates (destroys) protein of microoorganisms.

Answer 23

Moist Heat

Question 24

kills vegetative bacterial and
fungal pathogens and all viruses except endospores.
Temperature of 100 C for 30 minutes

Answer 24

Boiling or Flowing Steam

Question 25

steam under pressure; most powerful
sterilizing agent; kills all vegetative cells and their endospores
in 15min. It utilizes pressure (15psi) and temperature (121 ̊C).

Answer 25

Autoclaving

Question 26

kills all pathogens and most pathogens
by heating at 72 ̊C about 15sec. Used to sterilized milk.

Answer 26

Pasteurization

Question 27

Mechanism of action: damage DNA

Answer 27

RADIATION

Question 28

utilizes gamma rays, X rays or high energy electron
beams. It destroys DNA of microbes. Used for sterilizing pharamaceuticals,
medical and dental supplies. Not widespread used.

Answer 28

Ionizing radiation

Question 29

utilizes UV light, radiation not very penetrating but
damages DNA. Control of closed environment with UV lamp.

Answer 29

Nonionizing radiation

Question 30

Mechanism of action: Screen-like materials with pores small enough to retain
microorganisms

Answer 30

FILTRATION

Question 31

most harmful to bacteria

Answer 31

slow freezing

Question 32

Current standard

Answer 32

Use-Dilution Test

Question 32

Best known disinfectant screening test; potency of a
disinfectant is compared to that of phenol

Answer 32

Phenol coefficient test

Question 33

is one in which all organisms are descendants of the
same organism.

Answer 33

pure culture

Question 33

is one which is free of all life forms.

Answer 33

sterile medium

Question 34

practices that prevent the contamination of
growth media.

Answer 34

Aseptic techniques

Question 34

Anything in or on which we grow a microorganism is termed a

Answer 34

medium.

Question 35

the presence of unwanted microorganisms.

Answer 35

Contamination

Question 36

is the purposeful introduction of bacteria into a sterile
growth medium. A material is sterile when it has no living organisms
present.

Answer 36

INOCULATION

Question 37

wire
bent into a loop or circle at
the end.

Answer 37

Inoculating loop

Question 38

straight wire.

Answer 38

Inoculating needle

Question 39

a technique used to isolate a pure strain from a single
species of microorganism, often bacteria.

Answer 39

Streaking

Question 39

The streaking is done using a sterile tool, such as a cotton swab or
commonly an

Answer 39

inoculating loop.

Question 40

The isolation method most commonly used to get pure cultures is the

Answer 40

streak plate method.