Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology - Bacteria > Chapter 2: Bacterial structures > Flashcards

Chapter 2: Bacterial structures Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
0
Q

What bacterial structure gives rigid support, protects against osmotic pressure?

A

peptidoglycan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

peptidoglycan - function?

A

gives rigid support, protects against osmotic pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

peptidoglycan - chemical composition?

A

sugar backbone with peptide side chains cross-linked by transpeptidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what bacterial structure has the chemical composition of a sugar backbone with peptide side chains cross-linked by transpeptidase?

A

peptidoglycan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

cell wall (cell membrane of gram+) - function?

A

major surface antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what bacterial structure is the major surface antigen of gram+ bacteria?

A

cell wall/cell membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

cell wall (cell membrane of gram+) - chemical composition?

A

peptidoglycan for support

lipoteichoic acid induces TNF and IL-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which bacterial structure is composed of peptidoglycan and lipoteichoic acid?

A

cell wall (cell membrane of gram+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

outer membrane (gram-) - function?

A

major surface antigen

site of endotoxin (LPS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what bacterial structure is the major surface antigen of gram- bacteria?

A

outer membrane (containing LPS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

outer membrane (gram-) - chemical composition?

A

Lipid A induces TNF and IL-1

O polysaccharide is the antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what bacterial structure is composed of Lipid A and O polysaccharide?

A

outer membrane of gram-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

plasma membrane - function?

A

site of oxidative and transport enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what bacterial structure is the site of oxidative and transport enzymes?

A

plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

plasma membrane - chemical composition?

A

phospholipid bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what bacterial structure is composed of a phospholipid bilayer?

A

plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

ribosome - function?

A

protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what bacterial structure is the site of protein synthesis?

A

ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

ribosome - chemical composition?

A

50S and 30S subunits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

periplasm - function?

A

space between the cytoplasmic membrane and outer membrane in gram- bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what bacterial structure is the space between the cytoplasmic membrane and outer membrane of gram- bacteria?

A

periplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

periplasm - chemical composition?

A

contains many hydrolytic enzymes, including \beta-lactamases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

which bacterial structure contains many hydrolytic enzymes, including \beta-lactamases?

A

periplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

capsule - function?

A

protects against phagocytosis by macrophages and neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what bacterial structure protects against phagocytosis by macrophages and neutrophils?

A

capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

capsule - chemical composition?

A

polysaccharide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what bacterial structure is composed of polysaccharide? (2)

A

capsule

glycocalyx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the exception to capsule being composed of polysaccharide?

A

Bacillus anthracis, which contains D-glutamate amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the capsule of Bacillus anthracis composed of?

A

D-glutamate amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

pilus/fimbriae - function?

A

mediate adherence of bacteria to cell surface;

sex pilus forms attachment between 2 bacteria during conjugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what bacterial structure mediates adherence of bacteria to cell surface and forms attachment between 2 bacteria during conjugation?

A

pilus/fimbriae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

pilus/fimbriae - composition?

A

glycoprotein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what bacterial structure is composed of glycoprotein?

A

pilus/fimbriae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

flagellum - function?

A

motility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what bacterial structure is used for motility?

A

flagellum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

flagellum - chemical composition?

A

protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

spore - function?

A

resistant to dehydration, heat, and chemicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what bacterial structure is resistant to dehydration, heat, and chemicals?

A

spore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

spore - chemical composition? (3)

A

keratin-like coat
dipicolinic acid
peptidoglycan

39
Q

what bacterial structure is composed of a keratin-like coat, dipicolinic acid, and peptidoglycan?

A

spore

40
Q

plasmid - function?

A

contains a variety of genes for antibiotic resistance, enzymes, and toxins

41
Q

what bacterial structure contains a variety of genes for antibiotic resistance, enzymes, and toxins?

A

plasmid

42
Q

plasmid - chemical composition?

A

small circles of double-stranded DNA

43
Q

glycocalyx - function?

A

mediates adherence to surfaces, especially foreign surfaces (e.g., indwelling catheters). forms biofilms

44
Q

what bacterial structure mediates adherence to surfaces, especially foreign surfaces (e.g., indwelling catheters) as biofilms?

A

glycocalyx

45
Q

glycocalyx - chemical composition?

A

polysaccharide

46
Q

What are the steps to the Gram stain? (4)

A

1) Pour on crystal violet stain (a blue dye) and wait 60 seconds.
2) Wash off with water and flood with iodine solution. Wait 60 seconds.
3) Wash off with water and then “decolorize” with 95% alcohol.
4) Finally, counter-stain with safranin (a red dye). Wait 30 seconds and wash off with water.

47
Q

What color do Gram-positive cells appear on Gram stain? Why?

A

Blue (“I’m positively blue over you”).

Gram+ cells absorb the crystal violet and hold on to it in their thick cross-linked peptidoglycan cell wall.

48
Q

What cells stain blue on Gram stain?

A

Gram-positive

49
Q

What color do Gram-negative cells appear on Gram stain? Why?

A

Red (“No (negative) red commies”.
The crystal violet is washed off by the alcohol (alcohol partially dissolves the LPS-containing outer cell membrane) and the cells absorb the red safranin in their thin peptidoglycan cell wall.

50
Q

What cell stain red on Gram stain?

A

Gram-negative

51
Q

what is the layer just outside of the bacterial cytoplasmic membrane?

A

peptidoglycan layer (cell wall)

52
Q

What kind of cells have a peptidoglycan (cell wall) layer?

A

All bacterial cells, both Gram+ and Gram-

53
Q

transpeptidase - function?

A

catalyzes the formation of peptidoglycan linkages (composed of repeating disaccharides with 4 amino acids in a side chain)

54
Q

what enzyme catalyzes the formation of peptidoglycan linkages (composed of repeating disaccharides with 4 amino acids in a side chain)?

A

transpeptidase

55
Q

penicillin binds to and inhibits what enzyme in bacteria?

A

transpeptidase

56
Q

transpeptidase is inhibited by what antibiotic?

A

penicillin

57
Q

What is the difference in peptidoglycan cell wall between Gram+ and Gram- bacteria? (2)

A

1) thickness: Gram+ cell wall is very thick and Gram- cell wall is very thin
2) cross-linking: Gram+ cell wall has extensive cross-linking of the peptidoglycan amino-acid side chains. Gram- cell wall has a fairly simple cross-linking pattern.

58
Q

What is the composition of the Gram-positive cell envelope?

A

1) cytoplasmic membrane, with embedded proteins

2) peptidoglycan cell wall, with teichoic acid

59
Q

What important molecule is present in the peptidoglycan cell wall of Gram-positives?

A

teichoic acid

60
Q

teichoic acid is present in the peptidoglycan cell wall of which Gram bacteria?

A

Gram-positives

61
Q

What type of bacteria have a thick peptidoglycan cell wall?

A

Gram-positives

62
Q

what type of bacteria have a cell wall with more extensive cross-linking of peptidoglycan amino acid side chains?

A

Gram-positives

63
Q

What type of bacteria have a thin peptidoglycan cell wall?

A

Gram-negatives

64
Q

What type of bacteria have a cell wall with fairly simple cross-linking of peptidoglycan amino acid side chains?

A

Gram-negatives

65
Q

What polysaccharide acts as the major antigenic determinant of Gram-positive bacteria?

A

teichoic acid

66
Q

what is teichoic acid?

A

polysaccharide present in the peptidoglycan cell wall of Gram-positive bacteria

67
Q

What is the composition of the Gram-negative cell envelope?

A

1) cytoplasmic membrane, with embedded proteins
(periplasmic space)
2) peptidoglycan cell wall (thin), with murein lipoprotein
3) outer cell membrane, with LPS

68
Q

What important molecule is present in the peptidoglycan cell wall of Gram-negatives?

A

murein lipoprotein

69
Q

murein lipoprotein is present in the peptidoglycan cell wall of which type of bacteria?

A

Gram-negatives

70
Q

What is murein lipoprotein?

A

a small helical lipoprotein that originates in the peptioglycan layer of Gram-negative bacteria and extends outward to bind the third outer membrane

71
Q

What molecule is found in the unique third outer membrane of Gram-negative bacteria?

A

LPS

72
Q

Where is LPS found?

A

In the third outer membrane of Gram-negative bacteria

73
Q

What components of the cell envelope are unique to Gram-positive bacteria?

A

lipoteichoic acid

74
Q

What components of the cell envelope are unique to Gram-negative bacteria? (3)

A

LPS (endotoxin) (outer membrane)
periplasm
porins

75
Q

What are the 3 components in the structure of LPS?

A

1) O-specific side chain
2) Core polysaccharide
3) Lipid A

76
Q

What is O-antigen/ O-specific side chain?

A

outer carbohydrate chain of LPS (on the outer membrane of Gram-negatives) that extend into the surrounding media. They differ from one organism to another and are antigenic determinants.

77
Q

What is lipid A?

A

aka Gram-negative Endotoxin.
A disaccharide with multiple fatty acid tails reaching into the membrane. interior to the core polysaccharide of LPS on the outer membrane of Gram-negatives.

78
Q

What is endotoxin and how does it work?

A

Endotoxin = Lipid A
When Gram-negative bacteria are lysed by uman immune system, fragments of membrane containing Lipid A are released into the circulation, causing fever, diarrhea, and possibly fatal endotoxic (septic) shock.

79
Q

What are porins and where are they located?

A

Porins allow passage of nutrients.

Embedded in the gram-negative outer membrane.

80
Q

Which type of bacteria are vulnerable to antibiotics and chemicals that attack the peptidoglycan cell wall (penicillins and lysozyme)? Why?

A

Gram-positives are vulnerable.
The Gram-positive thickly-meshed peptidoglycan layer does not block diffusion of low molecular weight compounds, so substances that damage the cytoplasmic membrane (such as antibiotics, dyes, detergents) can pass through.

81
Q

Which type of bacteria are resistant to antibiotics and chemicals that attack the peptidoglycan cell wall (penicillins and lysozyme)? Why?

A

Gram-negatives are resistant.
The Gram-negative outer LPS-containing cell membrane blocks the passage of these substances into the peptidoglycan layer and sensitive inner cytoplasmic membrane.

82
Q

Which 2 tests can be used to visualize capsules under the microscope?

A

1) India ink stain

2) Quellung reaction

83
Q

How does the India ink stain allow you to detect bacterial capsules? What microbe does it detect?

A

India ink stain is not taken up by the capsule, so the capsule appears as a transparent halo around the cell.
This test is used primarily to identify the fungus (yeast) Cryptococcus neoformans

84
Q

How does the Quellung reaction allow you to detect bacterial capsules?

A

The bacteria are mixed with antibodies that bind to the capsule. When these antibodies bind, the capsule swells with water.

85
Q

opsonization - defn

A

the process of antibodies binding to the capsule, and allow macrophages and neutrophils to bind to (via Fc region) antibody and eat the encapsulated bacteria.

86
Q

Examples of encapsulated bacteria (8+1)

A 
"Even Some Super Killers Have (Pretty) Nice Big Capsules" or "SHiNE SKiS"
1) E.coli
2) Streptococcus pneumoniae
3) Salmonella
4) Klebsiella pneumoniae
5) Haemophilus influenzae
() Pseudomonus aerigonosa
6) Neisseria mengitidis
7) Group B Strep
8) Cryptococcus Neoformans (yeast)
87
Q

Why are asplenics at risk for severe infection?

A

Asplenics have decreased opsonizing ability (decreased macrophages and neutrophils) so they cannot easily clear infections

88
Q

Vaccines for S. pneumoniae, H. influenzae, and N. meningitidis target what structure?

A

capsule

Capsule + protein conjugate serve as the antigen in vaccines

89
Q

Vaccines in which the capsule + a protein conjugate serve as the antigen are available for which microbes? (3)

A

1) S. pneumoniae: PCV (Prevnar), PPSV (Pneumovax, no conjugated protein)
2) H. influenzae type B
3) N. meningitidis

91
Q

Which bacteria form endospores? What is their Gram stain and morphology?

A

Bacillus and Clostridium. Both are Gram-positive rods.

92
Q

Bacillus and Clostridium form what specialized structure?

A

endospores

93
Q

Endospores are resistant to what? (4)

A

heat (boiling)
cold
drying
chemical agents)

94
Q

What are the layers of the endospore protective coat? (5)

A

1) cell membrane
2) thick peptidoglycan mesh
3) another cell membrane
4) wall of keratin-like protein
5) outer layer called the exosporium

95
Q

When do spores form?

A

when there is a shortage of needed nutrients, and can lie dormant for years

96
Q

Which bugs are urease-positive? (8)

A

“CHuck Norris hates PUNKSS”

1) Cryptococcus
2) H. pylori
3) Proteus
4) Ureaplasma
5) Nocardia

Microbiology - Bacteria (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions