LAB MIDTERM TESTS

Question 1

identifies bacterium that can ferment glucose

Answer 1

purpose of Carbohydrate (Glucose) Fermentation test:

Question 2

broth turns YELLOW

Answer 2

positive carbohydrate test

Question 3

broth stays RED

Answer 3

negative carbohyrate test

Question 4

phenol red

Answer 4

what acts as a pH indicator in carbohydrate test?

Question 5

lowers pH below 7 (or 6.8)

Answer 5

carbohydrate test: if a bacterium ferments a sugar, what will happen to the pH of the medium?

Question 6

determines which fermentation route is used to utilize glucose; detects the production of acids (lowers pH)

Answer 6

purpose of Mixed Acid (MR) test:

Question 7

RED broth at a pH of 5 or less

Answer 7

pos. MR test

Question 8

broth stays YELLOW

Answer 8

neg. MR test

Question 9

Methyl Red

Answer 9

reagent used in MR test

Question 10

pH of 5 or lower

Answer 10

when does methyl red turn red in the MR test?

Question 11

determines which fermentation route is used to utilize glucose; detects precursors of Butanediol

Answer 11

purpose of Voges-Proskauer (VP) test:

Question 12

RED broth

Answer 12

pos. VP test

Question 13

broth stays YELLOW

Answer 13

neg. VP test

Question 14

Barritt’s A and Barritt’s B reagent

Answer 14

reagents used in VP test:

Question 15

precursors of Butanediol

Answer 15

what does Barritt’s A and B reagent detect in VP test?

Question 16

identifies bacterium that use citrate as a carbon source and form sodium carbonate (Na2CO3)

Answer 16

purpose of Citrate Agar test:

Question 17

blue agar

Answer 17

pos. Citrate test

Question 18

green agar

Answer 18

neg. Citrate agar test

Question 19

bromothymol blue

Answer 19

what acts as pH indicator in Citrate test?

Question 20

green

Answer 20

citrate test: pH indicator bromothymol blue in a NEUTRAL pH

Question 21

blue

Answer 21

citrate test: color of bromothyl blue in an ALKALINE pH

Question 22

identifies bacterium that possess the enzyme catalase (breaks down harmful hydrogen peroxide (HOOH) into water and oxygen

Answer 22

purpose of Catalase test:

Question 23

break hydrogen peroxide into water and oxygen

Answer 23

what does catalase enzyme do?

Question 24

bubbles

Answer 24

pos. Catalase test

Question 25

no bubbles

Answer 25

neg. Catalse test

Question 26

hydrogen peroxide

Answer 26

reagent used for Catalse test

Question 27

used to identify bacterium that produce cytochrome c oxidase (part of electron transport system); means they perform aerobic respiration to obtain energy

Answer 27

purpose of Oxidase test:

Question 28

PURPLE stain on streak

Answer 28

pos. Oxidase test

Question 29

no color change

Answer 29

neg. Oxidase test

Question 30

oxidase reagents

Answer 30

reagents used for Oxidase test

Question 31

aerobic respiration

Answer 31

what type of respiration does a bacterium use if it has cytochrome c oxidase?

Question 32

identifies bacteria that can hydrolyze starch; produce AMYLASE if they do

Answer 32

purpose of Start Hydrolysis test:

Question 33

clear zone around bacteria (means starch was DIGESTED); does NOT turn black from iodine

Answer 33

pos. starch hydrolysis test

Question 34

area around bacteria turns black (means starch was NOT digested)

Answer 34

neg. starch hydrolysis test

Question 35

Iodine

Answer 35

reagent used for Start Hydrolysis test:

Question 36

turns areas where starch was NOT digested black and leaves areas where starch WAS digested clear

Answer 36

how does iodine work in the Starch Hydrolysis test?

Question 37

identifies bacteria than can hydrolyze casein (makes milk white); uses skim milk agar plate

Answer 37

purpose of Casein Hydrolysis test:

Question 38

agar turns CLEAR

Answer 38

pos. Casein test

Question 39

no color change of agar

Answer 39

neg. Casein Hydrolysis test

Question 40

none

Answer 40

reagent used for Casein Hydrolysis test

Question 41

Sulfide Indole Motility

Answer 41

what does SIM stand for?

Question 42

identifies bacteria that produce hydrogen sulfide (through agar color)

Answer 42

purpose of H2S (hydrogen sulfide) Production:

Question 43

BLACK agar

Answer 43

pos. H2S (hydrogen sulfide) Production

Question 44

no color change

Answer 44

neg. H2S (hydrogen sulfide) Production

Question 45

none

Answer 45

reagent used for H2S production test:

Question 46

amylase

Answer 46

if bacteria can hydrolyze starch, what enzyme do they produce?

Question 47

identifies bacteria that produce indole (indole pyruvic acid); means they are capable of breaking down tryptophan

Answer 47

purpose of Tryptophan Degradation (part of SIM tube test):

Question 48

Kovac’s reagent turns RED

Answer 48

pos. Tryptophan Production test

Question 49

Kovac's reagent remains yellow

Answer 49

neg. Tryptophan Production test

Question 50

detects the presence of Indole

Answer 50

what does Kovac's reagent do in the Tryptophan Production test?

Question 51

tryptophan

Answer 51

what amino acid are bacteria capable of breaking down if they are positive for the Indole test?

Question 52

identifies bacteria that produce the enzyme Urease and perform Urea Hydrolysis; break down urea into CO2 + ammonia (NH3)

Answer 52

purpose of Urease test:

Question 53

HOT PINK broth (nikki minaj bby) when pH increase

Answer 53

pos. Urease test

Question 54

broth remains yellow

Answer 54

neg. Urease test

Question 55

phenol red

Answer 55

what is used as a pH indicator in Urease test?

Question 56

8.1

Answer 56

what pH does phenol red turn bright pink in the Urease test?

Question 57

CO2 + ammonia

Answer 57

produces of urea hydrolysis =

Question 58

INCREASE pH

Answer 58

if a bacterium produces urease, what happens to the pH of the culture medium?