Microbiology Lab Exam Houston Community College

Front 1

What are the two lymphocytes?

Back 1

B Cells and T Cells

Front 2

What are B Cells and where do they come from?

Back 2

They are lymphocytes. They come from Lymphoblasts which come from Lymphoid Stem cells. This comes from the Hematopoietic stem cell. B Cells mature in the bone marrow.

Front 3

What are T Cells and where do they mature?

Back 3

T cells are lymphocytes that come from lymphoid stem cells. T cells mature in the thymus gland.

Front 4

What are granulocytes?

Back 4

Granulocytes are granular leukocytes that are present bloodstream. They are neutrophils, basophils, mast cells and eosinophils.

Front 5

Agranulocytes 2 types

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two types: monocytes and Lymphocytes

Front 6

Leukocytes are

Back 6

white blood cells, they are white when they are unstained, but stain bright color when stained. Some have granules and some don't

Front 7

Monocytes: 2 types

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Dendritic Cells and macrophages.

Front 8

Lymphocytes: 2 types

Back 8

B Cells and T Cells

Front 9

Natural Killer Cells

Back 9

Related to T cells but display no antigen specificity.. They are active against cancer and virally infected cells.

Front 10

What do plasma cells produce?

Back 10

antibodies.

Front 11

Endospore

Back 11

dormant bodies that can withstand hostile conditions, they facilitate survival.

Front 12

What bacteria produce endospore (three types)

Back 12

Bacillus, Clostridium and Sporosarcina

Front 13

What is the endospore life cycle?

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Phase 1: vegetative; metabolically active growing stage
Phase 2: endospore; formed during adverse environmental conditions by a process called sporulation

Front 14

Microbiostatic

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inhibit the growth of microorganisms.

Front 15

microbicidal

Back 15

kills microbes

Front 16

TDH

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Thermal Death Time: Under specific temperature, under standard conditions, the time it takes for microbes to die

Front 17

What is the fastest most effect way to heat kill microbes

Back 17

Moist heat at high temperature

Front 18

Purpose of heating experiment

Back 18

1) to determine the effect of heat on bacteria
2) to understand the effect of heat on microorganisms.

Front 19

erythrocytes

Back 19

red blood cells: using blood agar, one can determine if the bacteria produces hemolysins

Front 20

Blood agar

Back 20

5% sheep blood. It grows fastidious bacteria. It is also a differential media.

Front 21

MacConkey's agar

Back 21

Selective and differential media. Bile salts and crystal violet (which inhibit the growth of Gram-Positive bacteria).
Lactose fermenting bacteria produce pink colonies. Non lactose fermenting bacteria produce clear colonies.

Front 22

Mannitol Salt agar

Back 22

selective and differential growth media.
High salt concentration (7.5%). Mannitol fermenters convert red dye to yellow. Non mannitol fermenters stay red.

Front 23

Mordant?

Back 23

gram's iodine. Reacts with crystal biolet to form a crystal violet iodine complex. The mordant fixes the dye to the inside of the cell, but still allows the dye to be washed away with alcohol if the cell is gram negative

Front 24

TSI Agar

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Triple Sugar Iron Agar; Used to differentiate and identify gram-neg enteric bacteria. Three sugars: glucose, lactose, and sucrose. Color indicator with Phenol Red: red=basic, yellow=acidic.

Front 25

Aerobes

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need O2 to for growth. Specifically, oxygen is needed by the electron transport chain

Front 26

Anaerobes

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grow without oxygen. Obligate anaerobes cannot survive in the presence of oxygen.

Front 27

Thioglycollate broth

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helps determine an organism's oxygen needs

Front 28

Selective Media

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One or more agents inhibit growth of certain microbes

Front 29

Differential Media

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Grows several types of bacteria but brings out visible differences in these bacteria (color changes).

Front 30

Enriched Media

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contains complex organic substances such as blood, serum, hemoblobin, or growth factors. Fastidious bacteria grow on an enriched media tailor made for their needs.

Front 31

Crystal Violet, Purpose

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Primary stain, cannot be decolorized (by alcohol ) on Gram + bacterial walls. Will wash off of Gram - walls.

Front 32

Gram's Iodine, Purpose

Back 32

It is a Mordant. Creates a complex with Crystal Violet and takes the dye into the cell. It is washed away by alcohol (the decolorizer) in a Gram - cell because it is washed away with the cell membrane lipids.

Front 33

Alcohol in Gram Staining, Purpose
95% Ethanol

Back 33

It is a decolorizer. It will wash away the Crystal Violet-Iodine Complex in a Gram - cell because the alcohol will wash away the membrane and the CV-I. It cannot wash away the CV-I from Gram + cells because the alcohol just shrinks the cell and secures the dye inside.

Front 34

Safranin, purpose

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Safranin is a counter stain that produces a orangish color for the gram negative cells that have been decolorized. They do not affect the gram positives.

Front 35

Gram Stain-Process

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1) Slides are prepared with heat fixing
2) stained with Crystal Violet for 1 minute and the rinsed with water.
3) Decolorized with 95% ethanol dropwise for about 15 seconds. Immediately rinse with water.
4) Counterstain with Safranin for 30 seconds and rinse.
5) dry

Front 36

Streak Plate Method (2 reasons)

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1) To isolate bacteria
2) To prepare and maintain a pure culture

Front 37

Mixed Culture

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(like in nature) Many microbes are growing together.

Front 38

Pure Culture

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A culture containing one type of microbe. Can be obtained by performing the streak plate method and isolating a colony of clones. These clones can be cultured to produce more of the same bacteria.

Front 39

Colonies

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large groups of a microbe that are visible to the human eye

Front 40

Purpose of heat fixation

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kills the bacteria and makes it stick to the glass slide.

Front 41

Nigrosin

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A negative stain

Front 42

Negative Staining

Back 42

For spirochetes such as Rodospirillum, bacterial capsule and endospore. Creates a dark background for the clear unstained bacteria. The stain is negatively charged while the bacteria is also negative, this is why staining on the bacteria does not occur

Front 43

bacteria in chains is ______

Back 43

Strepto-

Front 44

bacteria in sets of fours is ______

Back 44

tetrad

Front 45

Basic stains-how they work

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The dye is made of positive ions, which become attracted to and diffuse into the negatively charged bacteria.

Front 46

Basic stains - examples

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Methylene Blue
Crystal Violet
Safranin
All have positive dye ions

Front 47

Simple stain

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One dye is used

Front 48

Differential Stain

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two or more stains are used such as in the Gram stain where Crystal Violet is used first followed by Ethanol and then the Safranin stain

Front 49

A grape like cluster of bacteria is ______

Back 49

Staphylo-

Front 50

Diplo means______

Back 50

Two or in pairs

Front 51

Coccus

Back 51

Round

Front 52

Streptococcus Lactis

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oooooooooooo Coccus in a chain

Front 53

Staphylococcus aureus

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000
0000
000
a grape like cluster of cells

Front 54

sarcinae

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group of Eight

Front 55

Base and arm of microscope

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form the frame of microscope

Front 56

stage

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holds the slide

Front 57

sub stage condenser

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just below the stage. It condenses and focuses the light beam from the bulb.

Front 58

Pinion knob

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This know adjusts the sub stage condenser to adjust brightness and contrast

Front 59

Iris Diaphragm

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controls the amount of light going to the object

Front 60

Revolving Nosepiece

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this part holds the objective lenses. It can be rotated to choose between the 4x, 10x, 40x and 100x objective lenses

Front 61

4x

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Scanning objective

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10x

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Low power objective

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40x

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High dry objective

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100x

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oil-immersion objective

Front 65

coarse adjustment knob

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rapidly moves the stage up and down. Should only be used on 4x.

Front 66

Fine adjustment knob

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smaller of the two adjustment knobs. this can be used at 10x and above.

Front 67

oculars or eyepieces

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a set of lenses used to look into the stage view. Magnifies 10x. This amount is multiplied by the objective lens to determine the total amount of magnification

Front 68

illuminator or light source

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the light that is condensed by the sub stage condenser. The light comes from a bulb and creates a bright field.

Front 69

parfocal lenses

Back 69

when only minor adjustments in lenses is required between objective lenses, we call them parfocal.

Front 70

OIl immersion

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keeps the light from refracting too much. It condenses more of the light on the stage. The condenser should be brought closer to do this.

Front 71

Advantages of electron microscope

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has high magnification and resolution. High resolution is achieved because electrons produce much smaller waves than light waves, thus producing a more detailed image.

Front 72

Prokaryote-Unique qualities

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It has circular DNA
It has a nucleoid space, but no nucleus.
Has plasmids which contain some DNA for resistance and other adaptations. These can be shared between bacteria via conjugation, etc.
Has no organelles
Single cell life forms that may clump together in unique ways

Front 73

Eukaryones-Unique Qualities

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Has nucleus
Has

Front 74

E coli

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gram negative

Front 75

bacillus thuringiensis

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gram positive

Front 76

Serratia marcescens

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gram negative (red)

Front 77

Staphylococcus aureus

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Gram positive (purple)

Front 78

identification of pathogenic enterobacteria

Back 78

Mostly Gram -. Use MacConkey's. If they metabolize lactose, RED. If they don't metabolize lactose, YELLOW or CLEAR.

Front 79

bacillus subtilis

Back 79

Gram Positive

Front 80

Using thioglycollate broth in an agar tube, where will the strict anaerobic bacteria settle?

Back 80

On the bottom.

Front 81

Using thioglycollate broth in an agar tube, where will the facultative anaerobic bacteria settle?

Back 81

A wide range in the middle of the tube

Front 82

Using thioglycollate broth in an agar tube, where will the aerobic bacteria settle?

Back 82

At the top

Front 83

Using thioglycollate broth in an agar tube, where will the microaerophilic bacteria settle?

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mid to top middle range.

Front 84

what is the Kirby-Bauer Method

Back 84

Antiobiotic sensitivity testing

Front 85

If an antibiotic is unable to kill a baterium, the bacterium is said to be _________

Back 85

resistant

Front 86

If an antibiotic is able to kill a bacterium, it is ___________

Back 86

sensitive

Front 87

A zone of inhibition is ________

Back 87

the clear area around an antibiotic is a cultured media which represents antibiotic sensitivity.

Front 88

What agar is used for the Kirby-Bauer Method?

Back 88

Mueller-Hinton which is 30% beef solution and other nutrients. Used for microbial growth.