Microbiology Lab Final Exam Test Questions - Flashcards | StudyHippo.com (2022)

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Microbiology Lab Final Exam Test Questions - Flashcards | StudyHippo.com (1) Mya Day

7 July 2022

question

Give the steps of a PCR

answer

Heat reaction to 95 C to denature DNA Cool rxn to 55 C to allow primers to anneal Heat rxn to 72 C to allow Taq polymerase to bind

question

What machine is used to carry out a PCR reaction?

answer

thermocycler

question

How many cycles does a PCR rxn usually go?

answer

30

question

Name the 9 organisms used in the unknown lab

answer

Bacillus subtillis Enterobacter aerogenes Entero cloacae Escherichia coli Klebsiella pneumoniae Pseudomonas aeruginosa Salmonella typhimurium Staphylococcus aureus Staphylococcus epidermidis

question

Which organisms can ferment lactose?

answer

E. coli E. cloacae E. aerogenes K. pneumonia

question

Define caliform bacteria

answer

rod-shaped, Gram-negative, non-spore forming, and motile or non-motile bacteria which can ferment lactose with the production of acid and gas

question

Name the selective medias used in class

answer

Blood Agar Bile Esculin Mannitol Salt Agar (MSA) MacConkey Agar (MaC) Eosin Methylene Blue (EMB) Hektoen Enteric Agar (HEA) Xylose Lysine Desoxiolate (XLD)

question

Name the differential medias used in class

answer

O/F Glucose MRVP Catalase Oxidase Citrate Starch Indole TSI

question

What does the acronym IMViC stand for?

answer

indole methyl red vogues proskaver in citrate

question

What is the IMViC series of tests used for?

answer

used to differentiate gram negative rods

question

Which specific orgnaisms are the IMViC tests good at differentiating?

answer

Enterobacter

question

Define selective media

answer

designed to grow only specific bacteria but not others

question

Define differential media

answer

designed to show the difference between different organisms grown on

question

What does blood agar show?

answer

shows the types of hemolysis (ability to break down RBCs) of organisms

question

What are the 3 types of hemolysis?

answer

alpha beta gamma

question

Describe alpha growth on blood agar

answer

partial growth, green

question

Describe beta growth on blood agar

answer

total growth, clear

question

Describe gamma growth on blood agar

answer

nothing, still red

question

Bile esculin shows what?

answer

ability of organisms to tolerate bile and hydrolyze esculin

question

What two types of organisms is bile esculin good at differentiating?

answer

enterococci and streptococci

question

What reagant is added to bile esculin?

answer

ferric citrate

question

What could be the results of a bile esculin test?

answer

black is +

question

What two types of organisms usually grow on bile esculin?

answer

enterococci streptococci

question

MSA stands for

answer

Mannitol Salt Agar

question

MSA shows what?

answer

If the organisms produces acid products

question

MSA is used to identify which organism?

answer

S. aureus

question

What is the indicator in MSA whether the fermentation takes place or not?

answer

phenol red

question

What is the result of a positive MSA test?

answer

yellow is +

question

MaC stands for

answer

MacConkey Agar

question

MaC shows what?

answer

If the organism is a lactose fermenter

question

What are the possible outcomes of a MaC test?

answer

good growth indicates a gram negative bacterium that is not inhibited by crystal violet or bile. pink to red growth without bile indicates that the organism produces acid from lactose fermentation and is a probable coliform. colorless growth is a non lactose fermenting organism and noncoliform.

question

Can gram positive organisms grow on MaC?

answer

No

question

EMB stands for

answer

Eosin Methylene Blue

question

EMB shows what?

answer

tests if an organism is caliform

question

What are the possible results of an EMB test?

answer

dark growth indicates a lactose fermenter and acid production pink growth indicates lactose fermenter

question

HEA stands for

answer

Hektoen Enteric Agar

question

HEA shows what?

answer

indicates lactose fermentation and hydrogen sulfide production

question

HEA is used for?

answer

isolates salmonella & shigella bacteria

question

What are the possible results of a HEA test?

answer

pink growth indicates lactose fermenter and sulfur reducer

question

XLD stands for

answer

xylose lysine desoxiolate

question

XLD shows what?

answer

if an organism can ferment the sugar xylose to produce acid

question

XLD is used for?

answer

isolates salmonella & shigella bacteria

question

What are the possible results of XLD test?

answer

yellow indicates acid production red with some black growth indicates sulfur reduction

question

O/F in O/F glucose stands for

answer

oxidative/fermentation

question

O/F glucose tests show what?

answer

does the organism oxidize and/or ferment glucose

question

What could be the results of an O/F glucose test?

answer

2 tubes, one with oil (anaerobic) and one not: yellow in anaerobic means fermenting glucose but if yellow only in aerobic, then oxidizing glucose

question

MRVP stands for what?

answer

methyl red vouges proskaur

question

MRVP shows what?

answer

MR- tests for acid fermentation VP- can it ferment glucose

question

What could the results of vouges proskauer look like?

answer

red is + nothing is -

question

Catalase tests for what?

answer

does the organism have catalase

question

What could be the results of a catalase test?

answer

bubbles indicates catalase is present no bubles is -

question

Define catalase enzyme

answer

catalyzes the decomposition of hydrogen peroxide to water and oxygen (H₂O² → H₂O + O₂)

question

Oxidase tests for what?

answer

does the organism have cytochrom c oxidase

question

What could be the results of oxidase test?

answer

if the organism becomes blue after 20 secs then cytochrome c oxidase is present

question

Define oxidase enzyme

answer

an enzyme that promotes the transfer of a hydrogen atom from a particular substrate to an oxygen molecule, forming water or hydrogen peroxide.

question

Citrate tests for what?

answer

can the organism use citrate as its sole source of carbon

question

What could the results of a citrate test be?

answer

any amount of blue is + growth but no blue means citrate is utilized nothing is -

question

Starch tests for what?

answer

can the organism break down starch

question

What would a positive starch hydrolysis test look like?

answer

plate appeared white and cloudy where hydrolysis occurred, black is original color

question

Indole tests for what?

answer

does the organism have tryptophan

question

What will a positive indole test look like?

answer

red ring

question

What reagant is added to an indole test?

answer

kovac's reagant

question

TSI stands for

answer

triple sugar iron

question

TSI test for what?

answer

used to differentiate bacteria on the basis of glucose fermentation, lactose fermentation, sucrose, and sulfur reduction

question

What could be the results of a TSI test?

answer

cracks indicate gas production black precipitate indicates sulfur production red slant with yellow butt indicates glucose fermentation yellow slant indicates glucose and lactose fermentation

question

Define restriction digest

answer

aids in the protection of foreign DNA, restriction enzymes function by binding to the DNA and cutting out damaged portions. sites are short, usually 4-8 nucleotides

question

What is the charge of DNA?

answer

negative

question

What determines how far a molecule will move in gel electrophoresis?

answer

its molecular weight

question

Describe the role ethydium bromide gel electrophoresis

answer

binds to DNA and will fluoresce under a UV light

question

Define restriction enzymes

answer

an enzyme produced chiefly by certain bacteria, having the property of cleaving DNA molecules at or near a specific sequence of bases (restriction sites)

question

Define plasmid

answer

a genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium

question

Which test tests for acetoin?

answer

Vouges Proskauer

question

Give an example of a motile bacteria

answer

E. coli can be

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question

Give the steps of a PCR

answer

Heat reaction to 95 C to denature DNA Cool rxn to 55 C to allow primers to anneal Heat rxn to 72 C to allow Taq polymerase to bind

question

What machine is used to carry out a PCR reaction?

answer

thermocycler

question

How many cycles does a PCR rxn usually go?

answer

30

question

Name the 9 organisms used in the unknown lab

answer

Bacillus subtillis Enterobacter aerogenes Entero cloacae Escherichia coli Klebsiella pneumoniae Pseudomonas aeruginosa Salmonella typhimurium Staphylococcus aureus Staphylococcus epidermidis

question

Which organisms can ferment lactose?

answer

E. coli E. cloacae E. aerogenes K. pneumonia

question

Define caliform bacteria

answer

rod-shaped, Gram-negative, non-spore forming, and motile or non-motile bacteria which can ferment lactose with the production of acid and gas

question

Name the selective medias used in class

answer

Blood Agar Bile Esculin Mannitol Salt Agar (MSA) MacConkey Agar (MaC) Eosin Methylene Blue (EMB) Hektoen Enteric Agar (HEA) Xylose Lysine Desoxiolate (XLD)

question

Name the differential medias used in class

answer

O/F Glucose MRVP Catalase Oxidase Citrate Starch Indole TSI

question

What does the acronym IMViC stand for?

answer

indole methyl red vogues proskaver in citrate

question

What is the IMViC series of tests used for?

answer

used to differentiate gram negative rods

question

Which specific orgnaisms are the IMViC tests good at differentiating?

answer

Enterobacter

question

Define selective media

answer

designed to grow only specific bacteria but not others

question

Define differential media

answer

designed to show the difference between different organisms grown on

question

What does blood agar show?

answer

shows the types of hemolysis (ability to break down RBCs) of organisms

question

What are the 3 types of hemolysis?

answer

alpha beta gamma

question

Describe alpha growth on blood agar

answer

partial growth, green

question

Describe beta growth on blood agar

answer

total growth, clear

question

Describe gamma growth on blood agar

answer

nothing, still red

question

Bile esculin shows what?

answer

ability of organisms to tolerate bile and hydrolyze esculin

question

What two types of organisms is bile esculin good at differentiating?

answer

enterococci and streptococci

question

What reagant is added to bile esculin?

answer

ferric citrate

question

What could be the results of a bile esculin test?

answer

black is +

question

What two types of organisms usually grow on bile esculin?

answer

enterococci streptococci

question

MSA shows what?

answer

If the organisms produces acid products

question

MSA is used to identify which organism?

answer

S. aureus

question

What is the indicator in MSA whether the fermentation takes place or not?

answer

phenol red

question

What is the result of a positive MSA test?

answer

yellow is +

question

MaC stands for

answer

MacConkey Agar

question

MaC shows what?

answer

If the organism is a lactose fermenter

question

What are the possible outcomes of a MaC test?

answer

good growth indicates a gram negative bacterium that is not inhibited by crystal violet or bile. pink to red growth without bile indicates that the organism produces acid from lactose fermentation and is a probable coliform. colorless growth is a non lactose fermenting organism and noncoliform.

question

Can gram positive organisms grow on MaC?

answer

No

question

EMB stands for

answer

Eosin Methylene Blue

question

EMB shows what?

answer

tests if an organism is caliform

question

What are the possible results of an EMB test?

answer

dark growth indicates a lactose fermenter and acid production pink growth indicates lactose fermenter

question

HEA stands for

answer

Hektoen Enteric Agar

question

HEA shows what?

answer

indicates lactose fermentation and hydrogen sulfide production

question

HEA is used for?

answer

isolates salmonella & shigella bacteria

question

What are the possible results of a HEA test?

answer

pink growth indicates lactose fermenter and sulfur reducer

question

XLD stands for

answer

xylose lysine desoxiolate

question

XLD shows what?

answer

if an organism can ferment the sugar xylose to produce acid

question

XLD is used for?

answer

isolates salmonella & shigella bacteria

question

What are the possible results of XLD test?

answer

yellow indicates acid production red with some black growth indicates sulfur reduction

question

O/F in O/F glucose stands for

answer

oxidative/fermentation

question

O/F glucose tests show what?

answer

does the organism oxidize and/or ferment glucose

question

What could be the results of an O/F glucose test?

answer

2 tubes, one with oil (anaerobic) and one not: yellow in anaerobic means fermenting glucose but if yellow only in aerobic, then oxidizing glucose

question

MRVP stands for what?

answer

methyl red vouges proskaur

question

MRVP shows what?

answer

MR- tests for acid fermentation VP- can it ferment glucose

question

What could the results of the methyl red look like?

answer

red is + yellow is -

question

What could the results of vouges proskauer look like?

answer

red is + nothing is -

question

Catalase tests for what?

answer

does the organism have catalase

question

What could be the results of a catalase test?

answer

bubbles indicates catalase is present no bubles is -

question

Define catalase enzyme

answer

catalyzes the decomposition of hydrogen peroxide to water and oxygen (H₂O² → H₂O + O₂)

question

Oxidase tests for what?

answer

does the organism have cytochrom c oxidase

question

What could be the results of oxidase test?

answer

if the organism becomes blue after 20 secs then cytochrome c oxidase is present

question

Define oxidase enzyme

answer

an enzyme that promotes the transfer of a hydrogen atom from a particular substrate to an oxygen molecule, forming water or hydrogen peroxide.

question

Citrate tests for what?

answer

can the organism use citrate as its sole source of carbon

question

What could the results of a citrate test be?

answer

any amount of blue is + growth but no blue means citrate is utilized nothing is -

question

Starch tests for what?

answer

can the organism break down starch

question

What would a positive starch hydrolysis test look like?

answer

plate appeared white and cloudy where hydrolysis occurred, black is original color

question

Indole tests for what?

answer

does the organism have tryptophan

question

What will a positive indole test look like?

answer

red ring

question

What reagant is added to an indole test?

answer

kovac's reagant

question

TSI stands for

answer

triple sugar iron

question

TSI test for what?

answer

used to differentiate bacteria on the basis of glucose fermentation, lactose fermentation, sucrose, and sulfur reduction

question

What could be the results of a TSI test?

answer

cracks indicate gas production black precipitate indicates sulfur production red slant with yellow butt indicates glucose fermentation yellow slant indicates glucose and lactose fermentation

question

Define restriction digest

answer

aids in the protection of foreign DNA, restriction enzymes function by binding to the DNA and cutting out damaged portions. sites are short, usually 4-8 nucleotides

question

What is the charge of DNA?

answer

negative

question

What determines how far a molecule will move in gel electrophoresis?

answer

its molecular weight

question

Describe the role ethydium bromide gel electrophoresis

answer

binds to DNA and will fluoresce under a UV light

question

Define restriction enzymes

answer

an enzyme produced chiefly by certain bacteria, having the property of cleaving DNA molecules at or near a specific sequence of bases (restriction sites)

question

Define plasmid

answer

a genetic structure in a cell that can replicate independently of the chromosomes, typically a small circular DNA strand in the cytoplasm of a bacterium

question

Which test tests for acetoin?

answer

Vouges Proskauer

question

Give an example of a motile bacteria

answer

E. coli can be

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