Microbiology Quiz 2

Question 1

Organisms growing only in the presence of O2 are called

Answer 1

obligate aerobes

Question 2

organisms that are able to grow in the presence and absence of O2 are called

Answer 2

facultative anaerobes

Question 3

organisms that stricly only grown anaerobically and are actually harmed by the presence of O2 are called

Answer 3

obligate anaerobes

Question 4

which bacteria is a facultative anaerobe?

Answer 4

E. coli

Question 5

which bacteria is an obligate aerobe?

Answer 5

a. faecalis

Question 6

which bacteria is an obligate anaerobe?

Answer 6

C. sporogenes

Question 7

____________ are often used to create anaerobic conditions in a growth chamber. In the gas pack system. hydrogen and CO2 are produced. The palladium catalyst in the growth chamber catalyzes the formation of water from hydrogen and oxygen while CO2 prevents O2 from entering the chamber by creating pressure on the chamber wall

Answer 7

gas pack systems

Question 8

microorganisms that grown at tempreatures ranging from 015 degrees celsius are known as

Answer 8

psychrophiles

Question 9

organisms that can grow in cold temperatures, but grow optimally at temperatures between 25-45 degrees celsisus are called

Answer 9

psychotolerant

Question 10

organisms growing at temperatures between 25-45 degrees celsius are known as

Answer 10

mesophiles

Question 11

organisms that grow at temperatures above 55 degrees celisus are called

Answer 11

thermophiles

Question 12

which type of bacteria is a mesophile

Answer 12

S. aureus

Question 13

Which type of bacteia is a psychotolerant?

Answer 13

P. Plfuorescens

Question 14

Which type of bacteria is a thermophile?

Answer 14

Bacillus stearothermophilus

Question 15

bacteria that are able to tolerate high salt concentrations are called

Answer 15

halotolerant

Question 16

bacteria that thrive in high salt concentrations are known as

Answer 16

halophiles

Question 17

bacteria that are unable to handle high salt concentrations are

Answer 17

non-halophiles

Question 18

which bacteria is a non-halophile?

Answer 18

E. coli

Question 19

Which bacteria is a halotolerant?

Answer 19

S. aureus

Question 20

What makes EMB selective?

Answer 20

dyes limit growth of gram positive, selects for gram negative

Question 21

What makes EMB differential?

Answer 21

detection between lactose/non-lactose fermenting bacteria

Question 22

what makes MSA selective?

Answer 22

selects for halotolerant bacteria such as staphylococcus due to high salt concentrations

Question 23

what makes MSA differential?

Answer 23

contains mannitol and phenol red as a pH indicator

Question 24

what does lactose positive look like on an EMB palte?

Answer 24

black or dark center colonies or green metallic colonies

Question 25

what does lactose negative look like on an EMB plate?

Answer 25

clear to white colonies

Question 26

what does mannitol fermenter look like on a MSA plate?

Answer 26

Mannitol is reduced, pH drops and plate turns yellow

Question 27

what does non-mannitol fermenter looks like on a MSA plate?

Answer 27

mannitol is not reduced, no pH change, plate stays red

Question 28

which bacteria's colony description is lactose?

Answer 28

E. coli and the plate is green metallic

Question 29

which bacteria's colony description is non-lactose?

Answer 29

P. aeruginose and the plate is pink

Question 30

Which bacteria's color of agar is mannitol ferment?

Answer 30

S. aureus and the plate is yellow

Question 31

which bacteria's color of agar is non-mannitol ferment?

Answer 31

S. epidermidis and the plate is pink

Question 32

how is blood agar differential?

Answer 32

differentiates between hemolytic and non-hemolytic behavior

Question 33

what is hemolysins?

Answer 33

enzymes produced that destroy red blood cells

Question 34

what is partial hemolysis that causes a greening of the agar. The cells are left intact but the hemin is chemically altered

Answer 34

alpha hemolysis

Question 35

what is complete hemolysis that is caused by the obliteraion of the red blood cells. It produces a clear zone of agar and you can completely see through the palte?

Answer 35

Beta hemolysis

Question 36

what is no hemolysis, no effect on red blood cells?

Answer 36

gamma hemolysis

Question 37

which organism has beta hemolysis?

Answer 37

S. aureus and it's agar description is complete

Question 38

Which organism has alpha hemolysis?

Answer 38

A. faecalis and it's agar description is green

Question 39

Which organism has gamma hemolysis?

Answer 39

S. faecium and it's agar description is no color

Question 40

How is blood agar differential?

Answer 40

Differentiates between hemolytic and non-hemolytic behavior

Question 41

What is hemolysins?

Answer 41

Enzymes produced that destroy red blood cells

Question 42

What is partial hemolysis that causes a greening of the agar. The cells are left intact but the hemin is chemically altered.

Answer 42

Alpha hemolysis

Question 43

What is complete hemolysis that is caused by the obliteration of the red blood cells. It produces a clear zone of agar and you can completely see through the plate?

Answer 43

Beta hemolysis

Question 44

What is no hemolysis, no effect on red blood cells.

Answer 44

Gamma hemolysis

Question 45

Which organism has beta hemolysis?

Answer 45

S, aureus and it’s agar description is complete

Question 46

Which organism has alpha hemolysis?

Answer 46

A. faecalis and it’s agar description is green

Question 47

Which organism has gamma hemolysis?

Answer 47

S. faecium and it’s agar description is no color.

Question 48

Substances that are commonly applied to the skin are called

Answer 48

antiseptics

Question 49

Substances usually employed to kill microbes on inanimate objects are called

Answer 49

disinfectants

Question 50

Chemicals that are produced by the biochemical activity of a living organism that kills other living organisms are called

Answer 50

antibiotics

Question 51

How are antibiotic sensitivity determined?

Answer 51

Kirby-Bauer Method

Question 52

What is the Kirby-Bauer method?

Answer 52

Antibiotics are impregnated on thin paper disks. Disks are delivered by a mechanical dispenser or using sterile forceps. After incubation, the ‘zone of inhibition’ is measured. A small zone or no zone indicates that the organism is resistant to the antibiotic. A large zone indicates that the organism is susceptible to the antibiotic.

Question 53

What does the term selective toxicity mean?

Answer 53

‘Good antibiotics’ display selective toxicity and are limited in the type of organisms that they kill than are antiseptics and disinfectants.

Question 53

How do antibiotics attack the bacterial cell?

Answer 53

They kill other living organisms.

Question 54

Which type of media favors the growth of a particular organism while inhibiting the growth of other organisms?

Answer 54

Selective Media

Question 55

What type of media distinguishes between different types of bacteria?

Answer 55

Differential Media

Question 56

If bacterium is placed in a ________ solution, water will enter the cell and cause it to become rigid due to the cell wall?

Answer 56

Hypotonic

Question 57

When bacteria are placed in a _______ solution, water leaves and the plasma membrane shrinks away from the wall?

Answer 57

Hypertonic

Question 58

What is process called of the plasma membrane shrinking away from the wall?

Answer 58

plasmolysis