Module 2 Flashcards

1
Q

Cellular Morphology

A

size, shape, arrangement

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2
Q

um (micrometer)

A

1/1 000 000 meter

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3
Q

Average Cell Sizes

A

Average Cocci 1um X 1um

Average Rod 0.5umX3um

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4
Q

Cocci

A
Mostly round (some oval)
Can be seen in Chains, "grape like" clusters, pairs/diplococci, Tetrads (4), Sarcinae (8)
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5
Q

Rod

A

Can be seen as palisades (bacterial lay in sheets), acute angles, chaining

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6
Q

Coccobacilli

A

Short, oval coccoid rods

If bacterium is longer than it is wide, call it a rod!

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7
Q

Spirilla

A

slightly curved to a tight corkscrew

*don’t chain

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8
Q

Involution Forms

A

Dead, degenerating or dying bacteria

Result of poor growth conditions, antibiotic treatment

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9
Q

Bacterial Colony

A

Group of bacteria that divide and grow together to form visible entity on agar plates.

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10
Q

Colonial Morphology

A

Macroscopic appearance of bacterial colonies on agar plates

Color, consistency, hemolysis, size, colony edge appearance

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11
Q

Beta Hemolysis

A

Toxin in bacteria causes a clearing of RBC in agar plate surrounding the colonies on a plate

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12
Q

Flagella

A

Long appendages that enable the cell to move
*No flagella on cocci, rods only
Cannot be seen under light microscope unless stained
Can be seen with electron microscope

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13
Q

Atrichous

A

No flagella (trichous=hair)

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14
Q

Monotrichous

A

one flagella

Directional, rapid darting

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15
Q

Lophotrichous

A

tuft (up to 6 flagella)

Directional, rapid darting

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16
Q

Amphitrichous

A

Flagella on both ends

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17
Q

Peritrichous

A

Flagella around the cell

Cell is pushed in all directions, giving slow, non-directional movement, spinning, tumbling motion

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18
Q

Slide Motility

A

look at a liquid culture microscopically and see if bacteria move
nutrient broth, phosphate buffer
pH6.8 to 7.0
Incubated at RT overnight

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19
Q

Brownian Movement

A

Caused by molecular bombardment by saline molecules against the bacteria
Bacteria appear to vibrate/jiggle

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20
Q

Drifting or Streaming Movement

A

Everything moves in direction with the flow of the liquid

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21
Q

Advantages to Slide Motility

A

rapid results once the bacterial have grown in broth

may be able to tell flagella arrangement based on type of movement

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22
Q

Disadvantages to Slide Motility

A

Tedious and slow for large amounts of tests

Bacteria may not show motility if culture has gone past log phase

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23
Q

Motility Media - Plate Method

A

Outdated, spot of inoculum placed at edge of plate. Incubated and read for spreading growth across plate

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24
Q

Motility Media - Tube Method

A

Most common method, inoculated with straight wire halfway down tube. Incubated and read for growth.

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25
Q

Triphenyltetrazolium Chloride (TTC)

A

May be added to motility medium. TTC changes colour from colourless to red when reduced by bacteria

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26
Q

Advantages to Media Method

A

Fast and easy

Tubes may be incubated for several days and temperature may be varied

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27
Q

Disadvantages to Media Method

A

Obligate anaerobes that require oxygen for growth do no grow very well below the surface of the medium

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28
Q

Capsules

A

Glycocalyx - a polymer composed of polysaccharide (or polypeptide or combo of both)
organized and firmly attached to the cell wall
Appear mucoid and slimy in colonies
Initial culture will have more capsules than subsequent in vitro cultures
Capsule does not pick up stain (remains a colourless “halo” around cell)

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29
Q

Slime Layer

A

Unorganized “capsule”

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30
Q

Function of Capsules

A

Interfere with phagocytosis
More virulent than non-capsulated bacteria
Provide protective layer for bacteria
Allows bacteria to attach to surfaces

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31
Q

Capsular Swelling/ Quellung Reaction

A

When capsules are too small to be seen with light microscope, anti capsular antibody attaches to surface, making the capsule seem larger.

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32
Q

Cell wall composition

A

Peptidoglycan composed of 2 alternating sugars (N-acetylglucosamine (NAG) and N-acetylmuramic Acid (NAM)) to form rows of carbohydrate “backbone”
Tetrapeptide side chain composed of 4 amino acids attaches to NAM
Peptide cross bridge of 1-5 amino acids that bond tetrapeptide side chains

33
Q

Gram Positive Cell Wall

A

Thick layer of peptidoglycan
teichoic acids present
total thickness 30-60nm

34
Q

Gram Negative Cell Wall

A

Thin layer of peptidoglycan
no teichoic acids
outer phosopholipid membrane (toxic to many mammalian cells)
total thickness 10nm

35
Q

Cell wall damage

A

Antibiotics can break the peptidoglycan of the cell wall

Gram Positive more susceptible to damage

36
Q

Lysozyme

A

found in many body fluids, can break bonds between sugars in peptidoglycan

37
Q

Protoplast

A

Gram positive cell that has lost the cell wall

Bacterial cell only surrounded by membrane now

38
Q

Spheroplast

A

Gram negative cell with a lysed cell wall, but some outer membrane is still attached

39
Q

Hypotonic Solution

A

Water moves into cell causing rupture or lysis

Lower concentration of water in the cell than the surrounding solution

40
Q

Hypertonic Solution

A

Water leaves the cell causing shrinkage and collapse

Higher concentration of water in the cell than in surround solution

41
Q

Isotonic Solution

A

0.85% Saline (NaCl) has the same concentration of salt/water in the cell, no water moves in or out of the cell

42
Q

Gram Stain

A

Hans Christian Gram in 1884
Gram pos = Purple Bluish/black
Gram neg = Red/Pink

43
Q

Slide Prep - Broth

A

Transfer broth onto slide using swab, loop or pasteur pipet

44
Q

Slide Prep - Colony

A

Small portion of colony picked up with wire or wooden stick and mixed with a drop of saline on the slide

45
Q

Direct Smear

A

Prepared directly from the patients specimen

Often used for preliminary diagnosis

46
Q

If slide is too thick

A

cellular detail is not clear and bacteria could be missed

47
Q

If slide is too thin

A

slide will not represent the cells and bacteria in the sample and they may be missed

48
Q

Fixation

A

Heat: waved over flame or placed on warm plate for drying
Alcohol: flood completely dried slide with methanol for 1 min, then air dry again before staining (Best keeps their true morphology)

49
Q

Fixation accomplishes:

A

Sticks bacteria to the slide
kills most bacteria (But not spores)
Makes cells more permeable to stain
Prevents autolysis or changes in cells

50
Q

Underfixation

A

everything may wash off

remaining cells may be floating and poorly stained

51
Q

Overfixation

A

Poorly stained cells, usually pale

Shapes may be altered

52
Q

CIAS Staining Procedure

A
C) crystal violet for 1 min
rinse with water
All cells now deep purple
I) Iodine for 1 min
rinse with water
All cells now purple/bluish/black
A) decolourize with Acetone-alcohol until no more blue colour comes off slide
Color differentiation takes place
S) Safranin for 1 min
rinse with water
53
Q

Gram Positive Cell Colour

A

purple to bluish/black

54
Q

Gram Negative Cell Colour

A

pink to red

55
Q

Over Decolourization

A

Gram Pos appear Gram Neg

gram neg cells are not altered

56
Q

Under Decolourization

A

Gram Neg appear Gram Pos
Background and other cells appear Gram Pos
Gram positive cells not altered

57
Q

KOH Test

A

Place drop of Potassium Hydroxide on a slide
Stir colony with straight wire
Gram Neg organisms form a thread as wire is pulled away

58
Q

Antibiotic Susceptibility

A

If organism in question is inhibited by Gram Pos Spectrum, the organisms is gram positive.

59
Q

Factors resulting in disruption of cell wall (4)

A

Lysozome removes cell wall
Rough handing in preparation of slide
Old cells that are no longer in log phase
Antimicrobials inhibit cell wall formation

60
Q

Chromosome

A

DS DNA

1000-5000 genes per cell

61
Q

Plasmids

A

Carry genetic info like chromosomes

5-100 genes per cell

62
Q

How plasmids aid in survival of bacterial cells (5)

A

Resistance to antibiotics
Transfer or resistance factors to other bacterial cells
Allows bacteria to decompose complex organic compounds
Production of toxin harmful to host cells
Allow bacteria to mate and exchange genetic info

63
Q

Fimbriae

A

Not Flagella
hair like structures on Gram pos and Gram new cells
Allow bacteria to adhere to surfaces

64
Q

Pili

A

“sex pili”
1-2 per cell
Form connection between 2 cells when DNA is moving between them

65
Q

Cytoplasmic Membrane

A

located just below cell wall, surround cytoplasm
Phospholipid bilayer with proteins
Selective barrier regulating what enters and leaves the cell

66
Q

Diffusion

A

passive movement from area of high to low concentration

67
Q

Osmosis

A

Passive movement of water

68
Q

Facilitated Diffusion

A

Passive movement from area of low to high concentrations using carrier enzymes

69
Q

Permeases

A

Carrier enzymes that assist in facilitated diffusion

70
Q

Active Transport

A

Requires energy to transport materials from low to high concentration

71
Q

Endospores

A

Gram pos Rods only**
best seen in Death Phase
Spores are resistant to stain (appear refractile)
Heat resistant, disinfectant resistant, can survive in unfavourable conditions

72
Q

Sporulation

A

Formation of spores (takes up to 10 hours)
Copy of chromosome, some cytoplasm, and layers of peptidoglycan create spore (then surrounded by severall layers of spore coat)

73
Q

Ribosomes

A

Free granules, no endoplasmic reticulum
50S and 30S subunits join together to form 70S ribosomes
Function: protein synthesis

74
Q

Inclusions

A

Reserve deposits

75
Q

Volutin/Metachromatic granules (inclusion)

A

phosphate storage for ATP

76
Q

Polysaccharide granules (inclusion)

A

Glycogen and starch, food storage

77
Q

Lipid inclusion

A

Found in few bacteria

78
Q

Sulfur granules (inclusion)

A

energy reserve found in “sulfur bacteria”