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Microbial Cell Structure and Function Flashcards

1
Q

pneumonic device for Gram-negative and Gram-positive bacteria & their structure:

A

LONG PPT

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2
Q

what does LONG PPT stand for?

A

Lipopolysaccharide
Outer membrane
Negative
Gram?

Positive
Peptidoglycan (thick)
Teichoic acid

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3
Q

Common bacterial structures (11):

A
  • plasma membrane
  • gas vacuole
  • ribosomes
  • inclusions
  • nucleoid
  • periplasmic space
  • cell wall
  • capsules + slime layers
  • fimbriae + pili
  • flagella
  • endospore
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4
Q

type of common bacterial structure: selectively permeable barrier, mechanical boundary of cell, nutrient and waste transport, location of many metabolic processes (respiration, photosynthesis), detection of environmental cues for chemotaxis

A

plasma membrane

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5
Q

type of common bacterial structure: an inclusion that provides buoyancy for floating in aquatic environments

A

gas vacuole

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6
Q

type of common bacterial structure: protein synthesis

A

ribosomes

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7
Q

type of common bacterial structure: storage of carbon, phosphate, and other substances

A

inclusions

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8
Q

type of common bacterial structure: localization of genetic material (DNA)

A

nucleoid

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9
Q

type of common bacterial structure: in typical Gram-negative bacteria, contains hydrolytic enzymes and binding proteins for nutrient processing and uptake; in typical Gram-positive bacteria, may be smaller or absent

A

periplasmic space

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10
Q

type of common bacterial structure: protection from osmotic stress, helps maintain cell shape

A

cell wall

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11
Q

type of common bacterial structure: resistance to phagocytosis, adherence to surfaces

A

capsuoles and slime layers

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12
Q

type of common bacterial structure: attachment to surfaces, bacterial conjugation and transformation, twitching and gliding motility

A

fimbriae and pili

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13
Q

type of common bacterial structure: swimming ang swarming motility

A

flagella

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14
Q

type of common bacterial structure: survival under harsh environmental conditions

A

endospore

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15
Q

T/F: all bacteria has all of the common bacterial strucutres at one time

A

false

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16
Q

archaea are very similar to bacteria and their structures — the only unique bacteria HAVE that archaea dont is what?

A

capsules + slime layers

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17
Q

the cytoplasm is full of ______

A

proteins

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18
Q

inclusions look like _____

A

popcorn

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19
Q

T/F: inclusions are organelles

A

false!

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20
Q

hairs; attaches to surface

A

fimbriae

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21
Q

thin structure that separates cytoplasm from the environment

A

cytoplasmic membrane (or plasma or cell membrane)

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22
Q

functions of the cell membrane (3):

A

1) permeablility barrier (includes secretion, excretion, and translocation)
2) protein anchor
3) energy conservations

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23
Q

function of cell membrane: prevents leakage and functions as a gateway for transport of nutrients into, and wastes out of, the cell

A

permeability barrier

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24
Q

function of cell membrane: site of proteins that participate in transport, bioenergetics, and chemotaxis — aka transport, energy, and signals

A

protein anchor

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25
Q

function of cell membrane: site of generation and dissipation of the proton motive force; can be used to make ATP through ATP-synthase; separateps charge

A

energy conservation

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26
Q

the cell membrane separates charges, where _____ charges are on the inside and ______ are on the outside

A

negative; postive

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27
Q

the separation of charge by the cell membrane is a form of ____ _____

A

potential energy

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28
Q

permeability barrier of cell membrane: make something insdie (ex: toxin) and release it to the environment with a purpose

A

secretion

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29
Q

permeability barrier of cell membrane: getting rid of waste

A

excretion

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30
Q

permeability barrier of cell membrane: moving things from one part of the cell to another

A

translocation

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31
Q

bacteria do NOT use _____ or ________; everything has to go in/out via the cell membrane

A

endocytosis or exocytosis

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32
Q

most mitochondria use membranes like ______ do

A

bacteria

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33
Q

cell membrane can add structural ________

A

stability

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34
Q

most bacteria DONT use _______

A

sterols

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35
Q

what is the cytoplasmic membrane made out of?

A

lipid bilayer composed of phospholipids

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36
Q

the cell membrane is termed “_______;” means its both polar and non-polar

A

amphipathic

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37
Q

polar ends are _______

A

hydrophilic

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38
Q

non-polar tails are ______

A

hydrophobic

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39
Q

_______ levels of the cell membrane reflect the environment

A

saturation

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40
Q

membranes with ________ fatty acids are much more common in HOT temperatures

A

saturated

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41
Q

membranes with ________ fatty acids are much more common in COLD termperatures

A

unsaturated

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42
Q

which is more flexible? membranes with saturated or unsaturated fatty acid components?

A

unsaturated!

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43
Q

some bacteria have _____ within their lipid bilayer, which adds STRUCTURAL STABLILITY

A

hopanoids

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44
Q

what types of bacteris have hopanoids (2):

A
  • cyanobacteria
  • bacteria in warmer environments
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45
Q

the head groups of the lipid bilayer are _______ and ______

A

hydrophilic (water loving) + polar

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46
Q

the fatty acid tails of the lipid bilayer are _______ and ______

A

hydrophobic (water-hating) + nonpolar

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47
Q

unsaturated fats have _____ double bonds

A

2

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48
Q

T/F: all proteins within the cytoplasmic membrane are involved in some sort of transport

A

false

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49
Q

membrane protein: embedded within the membrane (AMPHIPATHIC - may or may not go all the way through the membrane); comprise 70-80% of the membrane proteins; carry out important function (transport, secretion, energy conservation)

A

integral membrane proteins

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50
Q

membrane protein: proteins only on one side of the plasma membrane; loosely connected to membrane; comprise 20 to 30% of the membrane proteins

A

peripheral protein

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51
Q

integral proteins comprise ____-____% of the membrane proteins

A

70 - 80%

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52
Q

peripheral proteins comprise ____-____% of the membrane proteins

A

20 - 30%

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53
Q

The bacterial cytoplasmic membrane is all of these EXCEPT:
a) selectively permeable phospholipid bilayer
b) amphipathic
c) a possible site for ATP production
d) used for endocytosis
e) structurally weak in most bacteria

A

d) used for endocytosis

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54
Q

important functions of INTEGRAL proteins (3):

A
  • transport
  • secretion and excretion
  • energy conservation
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55
Q

rigid structure that lies outside the plasma membrane; can contain peptidoglycan (only in bacteria)

A

cell wall

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56
Q

peptidoglycan is only found in the cell wall of what domain of microorganisms?

A

BACTERIA

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57
Q

_____ _______ is created in bacterial cells due to the rigidness of the cell wall

A

turgid pressure

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58
Q

functions of the cell wall (4 - in both gram+ and gram-)

A

1) provides shape to cell
2) protects from osmotic lysis
3) may contribute to pathogenenicity
4) protects from toxic substances

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59
Q

when too much water comes into the cell and bursts the cell wall

A

osmotic lysis

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60
Q

cell walls can be _______ – helps it to attach from tissue and prevent toxins from coming in

A

inflammatory

61
Q

in Gram-positive cells, ____% of the cell wall is peptidoglycan; “peptidoglycan sack”

62
Q

Gram-positive or Gram-negative? : TINY periplasmic space; some argue its not even there

A

Gram-positive

63
Q

Gram-positive or Gram-negative? : periplasmic space is FULL of enzymes

A

Gram- negative

64
Q

the outer membrane in Gram-negative bacteria helps with _______

65
Q

important component of BOTH gram-postive and gram-negative bacteria; made of sugars and amino-acids; unique for domain bacteria

A

peptidoglycan

66
Q

peptidoglycan is a ______ polymer

67
Q

two _____ ______ form the backbone of peptidoglycan

A

alternating sugars

68
Q

2 alternating sugars that form the backbone of peptidoglycan =

A
  • N-acetylglucosamine (NAG)
  • N-acetylmuramic acid (NAM)
69
Q

NAG =

A

N-acetylglucosamine

70
Q

NAM =

A

N-acetylmuramic acid

71
Q

along with alternating sugars, the meshlike polymer of peptidoglycan is also made of alternating ____ and ____ ______ _______

A

D- and L- amino acids

72
Q

____ _____ occurs with amino acids in peptidoglycan

A

cross-linking

73
Q

does diversity within peptidoglycan come from the alternating sugars or alternating amino acids?

A

amino acids

74
Q

NAG and NAM are always linked where?

A

beta (1,4) glycotic bond

75
Q

NAM is linked to a ________; can break

76
Q

found in saliva, tears, and sweat; can kill bacteria

77
Q

amino acids ALWAYS hang off the ______ in peptidoglycan

78
Q

how many amino acids come off of NAM?

79
Q

a lot of antibiotics target the ____ _____

80
Q

prevents peptides from linking up; transpeptidation; affects gram-POSTIVE

A

penicillin

81
Q

in E. coli, there is a ______ linkage between peptides

82
Q

in S. aureus, there is a ______ linkage between peptides

A

indirect (has an interbridge between them)

83
Q

in S. aureus, there is an _______ between peptides

A

interbridge

84
Q

what is the interbridge in S. aureus composed of?

A

5 glycines

85
Q

gram-positive cell walls are composed primarily of _______ (up to 90% of wall / 15 layers)

A

peptidoglycan

86
Q

gram-positive cell walls may also contain ________ acids (neg. charged)

A

teichoic acids

87
Q

teichoic acids are ______ charged

A

negatively charged

88
Q

functions of teichoic acids in Gram+ cell walls (4):

A

1) bind Ca+ and Mg2+
2) help maintain strucutre of the cell wall (covalently bonded)
3) protect from harmful substances
4) role in pathogensis

89
Q

glycerol/ribital phosphates; poly-alcohols; ONLY in Gram(+) and gives it a NEG. charge

A

teichoic acids

90
Q

teichoic acids attached to membrane lipids

A

lipoteiochoic acids

91
Q

some Gram(+) bacteria have a layer of _____ on the surface of peptidoglycan – helps with interactions with the ENVIRONMENT

92
Q

the cell wall is a lot less ______ compared to the membrane but still filters through

A

selective (termed “sive”)

93
Q

negatively charged acids on gram(+) bacteria); do NOT go all the way through the cell wall

A

teiochoic acid

94
Q

negatively charged acids on gram(+) bacteria); do go ALL the way through the cell wall

A

lipoteiochoic acids

95
Q

along with teichoic and lipoteichoic acids in the cell wall, gram(+) cell walls also have _____ ______ ______

A

wall-associated proteins

96
Q

detect nutrients, motility, etc. in the cell wall of gram(+) bacteria

A

wall-associated protein

97
Q

consist of a thin layer of peptidoglycan surrounded by an outer membrane

A

gram-negative cell wall

98
Q

gram-negative outer membranes are composed of what 3 things?

A
  • lipids
  • lipoproteins
  • lipopolysaccharide (LPS)
99
Q

T/F: gram-negative bacteria have teoichoic acids in their cell wall

100
Q

another lipid bilayer; more porous; a lot of lipids are replaced with this, so much that some call the outermembrane the ____ layer; only in gram-negative bacteria

A

LPS (lipopolysacchardides)

101
Q

how many layers of peptidoglycan are in gram-negative cells?

A

1-3 layers

102
Q

components of gram-negative cell walls (4):

A
  • peptidoglycan
  • periplasm
  • outer membrane
  • Braun’s lipoproteins
103
Q

component of gram-negative cell wall: up to 10% of the cell wall

A

peptidoglycan

104
Q

component of gram-negative cell wall: HUGE; may consitute 20-40% of cell volume

105
Q

the periplasm of gram-negative cell walls may constitute ____-____% of the cell’s volume

106
Q

there are many _____ present in the periplasm in gram(-) bacteria

107
Q

what kind of enzymes are present in the periplasm within gram(-) bacteria (3)?

A
  • hydrolytic enzymes
  • binding proteins
  • chemoreceptors
108
Q

component of gram-negative cell wall: lies outside the thin peptidoglycan layer; includes PORINS

A

outer membrane

109
Q

channels through qhich small, hydrophilic molecules (like sugars) can pass; 3 tubes stuck together; lined with water; all HYDROPHILIC substancces, neutral, and small substances pass

110
Q

waht kind of substances can pass through porins in gram(-)’s outer membrane (3)?

A
  • HYDROPHILIC substancces
  • neutral
  • small substances pass
111
Q

component of gram-negative cell wall: connect outer membrane to peptidoglycan; ANCHORS

A

Braun’s lipoproteins

112
Q

3 parts of LPS (lipopolysaccharide):

A

1) lipid A
2) core polysaccharide
3) O-specific polysaccharide

113
Q

lipid A is termed an _______

114
Q

part of LPS: varies depending on species; usually the same for the same species

A

core polysaccharide

115
Q

different names for O-specific polysaccharide (2):

A
  • O antigen (stimulate immune responses)
  • O-side chain
116
Q

part of LPS: varies based on the STRAIN

A

O-specific polysaccharide

117
Q

why is the O-specific polysaccharide sometimes called the “O-antigen”?

A

it can stimulate immune responses

118
Q

in LPS, the _____ _______ and ____ _____ ____ extend OUT from the cell

A

core polysaccharide + O side chain

119
Q

severity of salmonella is due to what part of LPS?

A

lipid A (endotoxin)

120
Q

importance/part of LPS: contributes NEGATIVE charge on cell surface =

A

core polysaccharide

121
Q

importance/part of LPS: helps stablize outer membrane structure; replaces phospholipids =

122
Q

importance of LPS: may contribute to attachment to surfaces and ______ formation; uses sugars sticking out helps attach bacteria to other bacteria

123
Q

groups of bacteria sticking together

124
Q

importance of LPS: creates a ________ barrier

A

permeability

125
Q

importance/part of LPS: may mutate to protect from host defenses =

126
Q

why is it good for the O antigen of LPS to be able to mutate easily?

A

immune systems arent able to recognize them; protects them from host defenses

127
Q

importance/part of LPS: acts as an “endotoxin” — AKA POISON

128
Q

a toxin inside out body that colonizes

129
Q

If you only had access to the cell wall of a bacterium, how would you determine if it was gram(+) or gram(-)?

A

look for presence/absence of teichoic acids AND LPS

130
Q

components of Osmotic Protection (2):

A
  • hypotonic environments
  • hypertonic environments
131
Q

component of Osmotic Protection: solute OUTSIDE the cell > solute INSIDE the cell

132
Q

component of Osmotic Protection: solute INSIDE the cell > solute OUTSIDE the cell

A

hypertonic

133
Q

component of Osmotic Protection: water moves INTO the cell and cell swells; cell wall protects from lysis

A

hypotonic environment

134
Q

component of Osmotic Protection: water LEAVES the cell; plasmolysis occurs

A

hypertonic environment

135
Q

where do bacteria want to be — hypo or hypertponic environments?

136
Q

if the cell wall is compromised, the cell could _____ if it is in a hypotonic environment

137
Q

process of a cell shriveling up in a hypertonic environment

A

plasmolysis

138
Q

T/F: fungi can withstand hypertonic environments better than bacteria mostly

A

T (ex: jelly)

139
Q

evidence of protective nature of cell wall: breaks the bond between NAG and NAM

140
Q

what bond does lysozyme break the bond between NAG and NAM?

A

Beta (1,4)

141
Q

evidence of protective nature of cell wall: _______ inhibits peptidoglycan synthesis; messes up peptide bonds between layers

A

penicillin

142
Q

if cells are treated with _____ or _____, they will lyse if they are put in a HYPOTONIC solution

A

lysozyme or penicillin

143
Q

what organisms do NOT have a cell wall and can survive in isotonic environments (2)?

A
  • protoplasts
  • spheroplasts
144
Q

survive in isotonic environments; Gram-POSITIVE cell with its wall removed

A

protoplasts

145
Q

survive in isotonic environments; Gram-NEGATIVE cell with its wall removed

A

spheroplasts

146
Q

no cell wall; plasma membrane more resistant to osmotic pressure; some are pathogenic; SMALLEST BACTERIA; have sterols

A

Mycoplasma

147
Q

what is typically rare for prokaryotes, used to stablize the cell membrane, and MYCOPLAMSA have them ?

148
Q

example of a sterol

A

cholesterol

Microbio (21 decks)

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