Unit 7 Quizzes

Question 1

If the photo below is of bacteria growing on TSA-blood agar medium, can you determine if the bacteria is Gram(+) or Gram(-)?

A) Yes, because TSA-blood medium is selective as well as differential.
B) No, because TSA-blood is only a differential, not selective medium.

Answer 1

B) No, because TSA-blood is only a differential, not selective medium.

Question 2

What type of blood hemolysis do you see on this CNA-blood agar medium?

A) beta or complete hemolysis
B) alpha or partial hemolysis
C) gamma, no hemolysis

Answer 2

B) alpha or partial hemolysis

Question 3

What is the supportive ingredient in Chocolate Agar?

Answer 3

lysed sheep red blood cells

Question 4

CNA blood agar differentiates according to bacterial

A) blood hemolysis
B) cell wall type
C) lactose fermentation
D) glucose fermentation

Answer 4

A) blood hemolysis

Question 5

Blood hemolyisis is associated with pathogenicity because:

A) Bacteria that can hemolyse blood can evade phagocytosis.
B) Blood hemolysis allows bacteria to live in the nose, throat and intestines.
C) Bacteria that can hemolize blood can utilize the nutrients in the blood to grow.
D) Blood hemolysis provides DNA for bacterial growth.

Answer 5

C) Bacteria that can hemolize blood can utilize the nutrients in the blood to grow.

Question 6

What does a clear growth (not pink) of bacteria signify on MacConkey medium?

A) The organism has the enzyme lactase
B) The organism is a coliform
C) The organism is a non-coliform
D) The organism is not a pathogen

Answer 6

C) The organism is a non-coliform

Question 7

What does bacterial growth with olive green color in the agar around the growth signify on TSA-Blood media?

A) Alpha hemolysis
B) Gamma hemolysis
C) Beta hemolysis

Answer 7

A) Alpha hemolysis

Question 8

All of the following provide nutrition in basic media EXCEPT:

A) digested yeast
B) digested soy
C) digested milk
D) agar

Answer 8

D) agar

Question 9

An organism growing on MacConkey medium with no color change in the medium (a clear growth pattern) is which of the following? Choose all that apply.

A) Lacks the enzyme lactase
B) Has the enzyme lactase
C) Coliform
D) Gram positive
E) Gram negative
F) Is likely a pathogen
G) Cannot ferment lactose
H) Can ferment lactose
I) Not likely pathogenic
J) Non-coliform

Answer 9

A) Lacks the enzyme lactase
E) Gram negative
F) Is likely a pathogen
G) Cannot ferment lactose
J) Non-coliform

Question 10

The bacteria that lives in the intestines and ferments lactose is:

A) Proteus vulgaris
B) Staphylococcus aureus
C) Priestia megaterium
D) E. coli

Answer 10

D) E. coli

Question 11

TSA-blood is:

A) differential
B) supportive
C) non differential
D) both supportive and differential

Answer 11

A) differential

Question 12

Blood is a source of all of the following EXCEPT:

A) amino acids
B) growth factors NAD and hemin
C) DNA
D) iron

Answer 12

C) DNA

Question 13

This bacteria growing on MacConkey ferments _______.

Answer 13

Lactose

Question 14

What is the differential ingredient in CNA blood?

A) lactose
B) whole sheep red blood cells
C) CNA
D) crystal violet and bile salts

Answer 14

B) whole sheep red blood cells

Question 15

An organism growing on TSA Blood that produces NO change in the red blood cells and has a white growth on top is which of the following?

A) A beta hemolyzer
B) An alpha hemolyzer
C) An organism that has hemolysins
D) An organism that ferments lactose
E) A gamma hemolyzer
F) An organism that has no hemolysins

Answer 15

E) A gamma hemolyzer
F) An organism that has no hemolysins

Question 16

The more __________ a bacterial species has, the more likely it is to be ________.

A) virulence factors……. normal flora
B) flagella…… beneficial
C) virulence factors….. pathogenic
D) hemolysins…… beneficial

Answer 16

C) virulence factors….. pathogenic

Question 17

Supportive media got it’s name because it contains agar, which provides a supportive surface for bacterial growth.

A) True
B) false

Answer 17

B) false

Question 18

The bacteria growing on this Chocolate agar plate show which type of hemolysis?

A) alpha or partial hemolysis
B) gamma or no hemolysis
C) beta or complete hemolysis
D) We can not determine hemolysis using Chocolate agar, because the blood has already been lysed.

Answer 18

D) We can not determine hemolysis using Chocolate agar, because the blood has already been lysed.

Question 19

A differential media:

A) selects for bacteria that have either a Gram(+) or Gram(-) cell wall
B) separates bacteria by size
C) supports the grow of many different types of bacteria
D) differentiates between bacteria based on metabolic processes different bacteria have

Answer 19

D) differentiates between bacteria based on metabolic processes different bacteria have

Question 20

CNA blood agar is:

A) differential
B) supportive
C) selective
D) selective and differential

Answer 20

D) selective and differential

Question 21

What does bacterial growth with no clearing in the agar around the growth signify on TSA-Blood media?

A) Alpha hemolysis
B) Beta hemolysis
C) Gamma hemolysis

Answer 21

C) Gamma hemolysis

Question 22

Blood plates are incubated in a candle jar because

A) the increased humidity enhances the growth of the bacteria
B) the low amount of oxygen decreases the chance of contamination
C) the low amount of oxygen enhances the expression of blood hemolysins
D) the candle jar increases the amount of oxygen and the bacteria grow better

Answer 22

C) the low amount of oxygen enhances the expression of blood hemolysins

Question 23

Bacteria that grow on Chocolate agar but not on other types of media are said to be:

Answer 23

fastidious

Question 24

Crystal violet is one selective ingredient in MacConkey. What is the other selective ingredient?

Answer 24

bile salts

Question 25

Which of the following bacteria is Gram(-)? A) Priestia megaterium, will not grow on CNA or Mac B) Staphylococcus aureus, grows on CNA C) Streptococcus oralis, will not grow on Mac D) E. coli, grows on Mac

Answer 25

D) E. coli, grows on Mac

Question 26

An organism growing on MacConkey medium with a bright pink color change in the medium is which of the following? A) Lacks the enzyme lactase B) Gram(-) non-lactose fermenter C) Cannot ferment lactose D) Can ferment lactose E) Has the enzyme lactase F) Gram negative lactose fermenter. G) Gram positive lactose fermentor H) Not likely pathogenic I) non-coliform J) Is likely a pathogen

Answer 26

C) Cannot ferment lactose G) Gram positive lactose fermentor

Question 27

Why is the inability to ferment lactose a virulence factor? A) Because the inability to ferment lactose means the bacteria normally line in the throat, and are therefor pathogenic. B) Because the inability to ferment lactose means the bacteria do not normally live in the gut and therefor may be pathogenic. C) Because the inability to ferment lactose means the bacteria normally live on the skin, and therefore are pathogenic. D) Because the inability to ferment lactose means the bacteria are normal gut flora and therefore pathogenic.

Answer 27

B) Because the inability to ferment lactose means the bacteria do not normally live in the gut and therefor may be pathogenic.

Question 28

The bacteria growing on the plate below produce _____________ to digest the blood in the media.

Answer 28

Hemolysin

Question 29

CNA blood agar selects for: A) Gram - B) rods C) Gram(+) D) cocci

Answer 29

C) Gram(+) D) cocci

Question 30

What is the differential sugar ingredient in MacConkey Media? (The pH Indicator Neutral Red is sometimes also considered a differential ingredient.)

Answer 30

Lactose

Question 31

What can you say aboutthis bacteria growing on MacConkey media? A) It is Gram(+) B) It is Gram(-) C) It does not ferment lactose D) It does not have blood hemolysins

Answer 31

B) It is Gram(-)

Question 32

What does a clearing in the agar around the bacterial growth signify on TSA-Blood media? A) Beta hemolysis B) Alpha hemolysis C) Gamma hemolysis

Answer 32

A) Beta hemolysis

Question 33

Blood plates are always incubated in a ______ ___.

Answer 33

candle jar

Question 34

If this bacteria grows on the Chocolate agar but won't grow on TSA-blood, it is termed: A) robust B) normal flora C) fastidious D) pathogenic

Answer 34

C) fastidious

Question 35

_________ _________ contain ingredients such as digested milk, soy, yeast or beef, which provide nutrients for growth.

Answer 35

Basic media

Question 36

Chocolate agar medium is: A) selective and differential B) supportive C) selective D) differential

Answer 36

B) supportive

Question 37

What advantage does the virulence factor seen in the photo give to the bacteria that have it? A) Makes it difficult to kill the bacteria with antibiotics. B) Allows bacteria to stick to surfaces. C) Produces hemolysins for blood lysis. D) Protects the DNA of the organism in a harsh environment.

Answer 37

D) Protects the DNA of the organism in a harsh environment.

Question 38

The large, Gram(+), rod-shaped bacterium that normally lives in the soil is? A) E. coli B) Priestia megaterium C) Proteus vulgaris D) Streptococcus oralis

Answer 38

B) Priestia megaterium