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Microbiology 260 > Lab exam 2: objectives > Flashcards

Lab exam 2: objectives Flashcards

1
Q

What is the name of the pink oxygen indicator?

methylene pink

resazurin

methylene blue

phenol red

A

resazurin

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2
Q

How should a microbe ONLY growing at the very top of a thioglycollate tube be decribed with respect to oxygen?

Facultative anaerobe

Obligate anaerobe

Obligate aerobe

A

Obligate aerobe

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3
Q

How should a microbe growing in the pink and below the pink in a thioglycollate tube be classified with respect to oxygen?

Obligate anaerobe

Facultative anaerobe

Aerobe

Cannot be determined

A

Facultative anaerobe

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4
Q

How should a microbe growing ONLY without oxygen be classified with respect to oxygen?

Aerobe

Facultative anaerobe

Obligate anaerobe

A

Obligate anaerobe

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5
Q

A microbe that grows with and without oxygen is a(n):

obligate aerobe

obligate anaerobe

facultative anaerobe

A

facultative anaerobe

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6
Q

An organism that grows well in the incubator and slightly less in the GasPak is a(n)

Facultative anaerobe

Obligate anaerobe

Obligate aerobe

Cannot be determined

A

Facultative anaerobe

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7
Q

What is the name of the enzyme that hydrolyzes casein?

amylase

casease

lipase

A

casease

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8
Q

How will you know if the bacteria hydrolyze casein?

A clear zone surrounding the growth will be visible following incubation.

A cloudy zone surrounding the growth will be visible following incubation

The area surrounding the growth will turn dark purple.

A

A clear zone surrounding the growth will be visible following incubation.

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9
Q

Starch is hydrolyzed using:

intracellular enzymes

extracellular enzymes

A

extracellular enzymes

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10
Q

Casein is a:

nucleic acid

protein

carbohydrate

A

protein

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11
Q

The products of protein hydrolysis are:

monosaccharides

amino acids

glycerol and fatty acids

A

amino acids

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12
Q

A product of starch hydrolysis is:

monosaccharide

amino acid

glycerol

A

monosaccharide

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13
Q

PCR is an abbreviation for

Polymerase carboxyl reaction

Polymerase chain reaction

Polymer chain reaction

A

Polymerase chain reaction

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14
Q

PCR is like a molecular xerox machine for DNA. The process is designed to make multiple copies (amplify) of a desired gene or other short DNA fragment.

True

False

A

True

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15
Q

PCR rapidly _______ the amount of DNA in a sample. This decreases the need for making cultures or carrying out complex purification techniques. Once multiple copies of DNA are made, they can be used in various ways, ranging from research to _________________.

Decreases….diagnostics and forensics

Increases….culturing bacteria and fungi

Increases…diagnostics and forensics

A

Increases…diagnostics and forensics

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16
Q

Since DNA is tiny and colorless, the resulting PCR products cannot be visualized in the reaction tube. Agarose gel electrophoresis will allow visualization of the DNA as bands in the gel.

True

False

A

True

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17
Q

PCR makes it possible to amplify a target DNA from a few copies to at least_______ of copies in a few hours.

Hundreds

Thousands

Millions

A

Millions

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18
Q

________________are short single-stranded DNA strands of a known sequence that indicate where DNA amplification will begin.

DNA polymerase

Primers

Nucleotides

A

Primers

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19
Q

Taq polymerase is an example of a DNA polymerase used in PCR. This enzyme works at

Low temperatures

Relatively high temperatures

High salt concentration

A

Relatively high temperatures

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20
Q

The machine used in PCR is called the

Thermal cycler

PCR prepper

Thermal vent polymerase

A

Thermal cycler

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21
Q

In the _________ step, primers bind to the test DNA. This occurs around 45-65 degrees C. The temperature allows the primers to complementary base pair to their target sequences on opposite strands of the template DNA.

Denaturation

Annealing

Extension

A

Annealing

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22
Q

In the ________ step, target DNA is heated to 92-96 degrees C so the double stranded DNA will separate into 2 strands. The heat breaks the hydrogen bonds holding the double-stranded DNA together.

Denaturation

Priming

Annealing

A

Denaturation

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23
Q

The _______ step occurs around 72 degrees C. The DNA polymerase uses the raw materials in the form of nucleotides to extend the molecule and produce 2 complete strands of DNA.

Denaturation

Priming

Extension

A

Extension

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24
Q

Which of the following ingredients must be in a PCR reaction?

DNA template

Primers

Nucleotides

DNA polymerase with the appropriate buffer

All of the above

A

All of the above

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25
Q

Your unknown is a member of the Enterobacteriaceae family (enterics). See index or research online if needed. Therefore, it will be

Gram-positive

Gram-negative

A

Gram-negative

26
Q

The description of your Gram-positive colony may be taken from your______plates. Read PEA and Mac labs.

PEA or TSA (nutrient agar)

MacConkey or TSA (nutrient agar)

A

PEA or TSA (nutrient agar)

27
Q

When you perform your Gram stain from your MacConkey plate, you should see

Gram-positive cocci

Gram-negative rods or coccobacilli

Gram-positive rods or coccobacilli

A

Gram-negative rods or coccobacilli

28
Q

Please see your lab schedule for this question. We will be further purifying the Gram-negative unknown away from the Gram-positive contaminant. Therefore, we will pick a colony of the Gram-negative microbe and

grow it in the Gas Pak

grow it on PEA

streak for isolation again onto a TSA plate

A

streak for isolation again onto a TSA plate

29
Q

Please refer to your lab schedule. Your unknown may be ______________. Select all of the correct choices.

Serratia marcescens

Enterococcus faecalis

Escherichia coli

Bacillus subtilis

Klebsiella pnuemoniae

Proteus vulgaris

Staphylococcus aureus

A

Serratia marcescens

Escherichia coli

Klebsiella pnuemoniae

Proteus vulgaris

30
Q

Please read PEA and MAC labs. The description of your Gram-negative colony may be taken from your______plates.

PEA or TSA (nutrient agar)

MacConkey or TSA (nutrient agar)

A

MacConkey or TSA (nutrient agar)

31
Q

With regard to the phenol red broth, what is the function of the Durham tube?

collect gas

trap aerobes

pH indicator

A

collect gas

32
Q

SIM medium is inoculated with a _________ because we can check for _______.

needle….oxygen use

loop….turbidity

needle…motility

A

needle…motility

33
Q

SIM medium may be used to:

differentiate pathogens that cause neurological disorders

differentiate Enterobacteriaceae

differentiate respiratory pathogens

A

differentiate Enterobacteriaceae

34
Q

The sole carbon source in citrate medium is______. This test will help you distinguish among the unknowns.

citrate

glucose

phosphate

35
Q

All of the tests we are setting up for this lab will help differentiate your unknown, so it is important to inoculate carefully.

False

True

36
Q

You will inoculate your unknown into the Enteropluri tube. This test will allow us to perform multiple tests in a single tube. There are ______ individual chambers.

2

6

12

37
Q

A(n) _______________________ is the material used to separate DNA fragments.

Reaction mix

Buffer

Agarose gel

A

Agarose gel

38
Q

The _________are where you put the DNA in a gel at the top.

Dips

Wells

Gels

39
Q

________bands of DNA will migrate the farthest in the agarose gel.

Heavier

Lighter

40
Q

TAE or TBE are types of ___________used during the electrophoresis process.

Enzyme

Buffer

Gel

41
Q

DNA is negatively charged and will run toward the positive pole in gel electrophoresis.

True

False

42
Q

A phenol red broth after incubation appeared yellow with a bubble in the Durharm tube. How would you record this tube?

no reaction

acid without gas

acid and gas

protein degradation

A

acid and gas

43
Q

In the phenol red broths, if an organism released an acidic product, the pH indicator turns:

Pink

Yellow

Red

Blue

A

Yellow - pH below 6.8 (acidic)

Red - neutral

Pink - pH above 7.4 (alkaline)

44
Q

The black color in a SIM tube indicates the bacteria produced a substance called___________.

FeSO4

indole

H2S

FeS

45
Q

With regard to the previous question on SIM medium, the actual chemical representing the black precipitate is ___________.

indole

H2S

FeSO4

FeS

46
Q

A bright red color is observed after an indole test is performed from SIM medium. Is the indole test positive or negative for this organism?

Positive

Negative

47
Q

Would the indole test work if tryptophan was accidentally left out of this media?

Yes

No

48
Q

Name the reagent added to perform the indole test.

Phenol Red

Methyl Red

Ferric chloride

Kovak’s reagent

A

Kovak’s reagent

49
Q

An organism that utilizes citrate will appear:

as no color change with no growth

blue or no color change, but with growth

A

blue or no color change, but with growth

50
Q

MacConkey agar is:

selective and differential

enriched and differential

selective only

differential only

A

selective and differential

51
Q

The use of the streak plate technique is to:

A

obtain isolation of individual species from a mixed sample.

52
Q

How many times will you dip into your original culture when performing a streak plate?

A

only once, to streak the first quadrant.

53
Q

The gram stain is a:

Simple stain

Differential stain

Negative stain

A

Differential stain

54
Q

Describe 2 methods for providing anaerobic growth conditions:

A

Fluid thioglycolate broth (FTB)
Anaerobic jar (gaspak)

55
Q

Know which components of the medium reduce oxygen to water:

Sodium thioglycolate

L-cystine

A

Sodium thioglycolate

L-cystine

56
Q

Interpret the results of a citrate test:

Blue

no color change (growth)

no color change (no growth)

A

Blue - Positive (+ citrate permease is present)

No color change (growth) - Positive

No color change (no growth) - Negative

57
Q

Define Coliforms:

most are normal inhabitants of the human intestinal tract; their presence in the environment may be evidence of fecal contamination.

A

a subgroup of Enterobacteriaceae that produce acid and gas from lactose fermentation.

58
Q

Define Enterics:

Pathogenic bacteria of bacterial gastroenteritis.

A

bacteria of the intestines, and may refer to gut flora, which are always present and usually harmless.

59
Q

Coliforms are normal gram-_______ inhabitants of the human ________.

positive…skin

negative…skin

positive…intestinal tract

negative…intestinal tract

A

negative…intestinal tract

59
Q

Match the types of arrangements:

Diplo- Chains
Strepto- Irregular clumps, grapes
Staphylo- Pairs

A

Diplo - pairs
Strepto- chains
Staphylo - irregular clumps, grapes

59
Q

Phenylethyl alcohol agar (PEA) is mostly selective for _________ organisms. This is because PEA inhibits the growth of many Gram-negative while only some Gram-positive organisms. PEA is _________________.

Gram-positive….selective and differential

Gram-positive….selective only

Gram-negative…selective and differential

Gram-negative…selective only

A

Gram-positive….selective only

60
Q

A hot pink color was observed on colonies growing on MacConkey agar. These organisms are capable of _______________ fermentation.

glucose

lactose

sucrose

galactose

Microbiology 260 (8 decks)

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