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Lecture 2 (bacterial Cell structure with some Archaea stuff) Flashcards

1
Q

Prokaryotes differ from eukaryotes in size and _____

A

simplicity

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2
Q

most prokaryotes lack

A

internal membrane systems

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3
Q

is the term prokaryotes becoming blurred

A

yes

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4
Q

prokaryote comes form the Greek words for

A

pre-nucleus

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5
Q

Eukaryote comes form the Greek words for

A

true nucleus

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6
Q

Are most bacteria monomorphic

A

Yes

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7
Q

What does monomorphic mean

A

one shape

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8
Q

Are a few bacteria pleomorphic

A

yes

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9
Q

what does pleomorphic mean

A

multiple shapes

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10
Q

What are the three basic bacteria shapes

A
  • Bacillus (rod-shaped)
  • Coccus (spherical)
  • Spiral
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11
Q

what are the three types of spiral shapes

A
  • Spirillum
  • Vibrio
  • Spirochete
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12
Q

What is Spirillum

A

Spiral shaped with one or more twists

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13
Q

What is Vibrio

A

type of Spiral shaped

-Curved rod

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14
Q

What is Spirochete

A
  • Type of Spiral shape

- Flexible, helical, spirals

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15
Q

Diplo-

A

pairs

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16
Q

Staphylo-

A

Clusters

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17
Q

Strepto-

A

Chains

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18
Q

The division in staphylo- is in _____ planes

A

multiple

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19
Q

The division in Strepto- is in ____ planes

A

a single plane

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20
Q

Organisms that are variable in shape

A

pleomorphic

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21
Q

Network of long, multinucleate filaments

A

mycelium

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22
Q

what is the smallest bacteria

A

Mycoplasma (0.3 micrometers)

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23
Q

The average rode size

A

1.1-1.5 x 2-6 micrometers

size of E. coli

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24
Q

Epulopiscium fishelsoni is a ___ (size) bacteria

A

very large - 600 x 80 micrometers

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25
Q

____ cells have a larger surface area to volume ratio

A

smaller cells

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26
Q

Function of plasma membrane in bacteria

A
  • Selectively permeable barrier
  • Mechanical boundary of cell
  • Nutrient and waste transport
  • location of many metabolic processes (respiration, photosynthesis)
  • detection of environmental cues for chemotaxis
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27
Q

What is the function of the Gas Vacuole in bacteria

A

an inclusion that provides buoyancy for floating in aquatic environments

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28
Q

What is the function of the ribosomes in bacteria

A

Protein Synthesis

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29
Q

What is the function of inclusions in bacteria

A

storage of carbon, phosphate, and other substances

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30
Q

What is the function of nucleotide in bacteria

A

localization of genetic material (DNA)

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31
Q

What is the function of Periplasmic space in bacteria

A
  • in typical Gram-negative bacteria, contains hydrolytic enzymes and binding proteins for nutrient porcessing and uptake
  • In typical Gram-positive bacteria it may be smaller or absent
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32
Q

what is the function of the cell wall in bacteria

A
  • protection form osmotic stress

- helps maintain cell shape

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33
Q

What is the function of Capsules and slime layers in bacteria

A
  • Resistance to phagocytosis

- Adherence to surfaces

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34
Q

What is the function of Fimbriae and pili in bacteria

A
  • Attachement to surfaces
  • bacterial conjugation and transformation
  • Twitching and gliding motility
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35
Q

What is the function of Flagella in bacteria

A
  • Swimming and Swarming motility
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36
Q

What is the function of endospore in bacteria

A

Survival under harsh environmental conditions

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37
Q

What are the components of the bacterial cell envelope

A
  • Plasma membrane
  • Cell wall
  • Layers outside the cell wall
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38
Q

do some bacteria have an internal membrane system

A

yes

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39
Q

is a plasma membrane an absolute requirement for all living organisms

A

yes

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40
Q

Bacterial membranes lack _______, which is present in Eukaryotic membranes but they do contain _____

A

sterols (like cholesterol), but do contain Hopanoids

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41
Q

What is the function of Hopanoids in the bacterial membranes

A

is a sterol-like molecule and stabilizes the membrane

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42
Q

are Hopanoids found in petroleum

A

yes

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43
Q

Lipid composition of bacterial membranes varies with

A

environmental conditions (ex. Temperature)

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44
Q

do many bacteria have plasma membrane infoldings

A

yes

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45
Q

some Archaeal membranes have a ____ structure instead of a bilayer structure

A

monolayer

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46
Q

Are Archaeal membranes composed of lipids that differ chemically from those of Bacteria and Eukaryotes

A

Yes

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47
Q

bacterial and eukaryotic lipids contain ___ bonds while Archaeal lipids contain ____ bonds

A

Ester, Ether

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48
Q

bacterial and Eukaryotic lipids have ___ hydrocarbons attached to glycerol

A

2

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49
Q

special features of Archaeal lipids

A
  • Ether bonds
  • Branched molecules
  • Tetraethers (some) (note these make a monolayer)
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50
Q

what are the functions of the Plasma membrane

A
  • Encompasses the cytoplasm
  • Selectively permeable Barrier
  • Interacts with External environment
    • receptors for detection of and response to chemical surroundings
    • Transport systems
    • Metabolic processes
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51
Q

Substance in which nucleotide, ribosomes, inclusion bodies, plasmids, and cytoskeletal filaments are suspended

A

Cytoplasm of Bacteria and Archaea

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52
Q

The cytoplasm of bacteria and Archaea lack _____ and are composed largely of ___

A
  • lack organelles bound by unit membranes

- composed largely of water

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53
Q

Homologs of all 3 eukaryotic cytoskeletal elements have been identified in bacteria. What are they

A
  • Actin
  • Intermediate filaments
  • Microtubules
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54
Q

Are the functions of the cytoskeleton in bacteria similar to in eukaryotes

A

yes

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55
Q

Function of microtubule homolog FtsZ in Bacteria

A

Cell division

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56
Q

Microtubule homolog FtsZ is widely observed in

A

bacteria and archaea

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57
Q

Function of microtubule homolog BtubA/BtubB in Bacteria

A

Unknown

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58
Q

microtubule homolog BtubA/BtubB is only observed in ____ and thought to be encoded by

A

Only observed in Prosthecobacter spp

thought to be encoded by eukaryotic tubular genes obtained by horizontal gene transfer

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59
Q

Function of microtubule homolog TubZ in bacteria

A

Possibly plasmid segregation

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60
Q

Microtubule homolog TubZ is encoded by ____ and observed in

A

large plasmids and observed in members of the genus Bacillus

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61
Q

Function of actin homolog MamK in bacteria

A

Positioning magnetosomes

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62
Q

Function of actin homolog MreB/Mbl in bacteria

A

Helps determine cell shape
may be involved in chromosome segregation
localizes proteins

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63
Q

Function of actin homolog ParM in bacteria

A

Plasmid Segregation

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64
Q

Actin homolog MamK is observed in

A

magnetotactic species

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65
Q

Actin homolog MreB/Mbl is observed in

A

Most rod-shaped bacteria

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66
Q

Actin homolog ParM is ____ encoded

A

plasmid

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67
Q

function of intermediate filament homolog CreS (Crescentic)

A

Induces curvature in curved rods

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68
Q

Intermediate filament homolog CreS (crescentin) is observed by

A

Caulobacter crescentus

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69
Q

What are two unique bacterial cytoskeletal proteins

A

MinD and ParA

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70
Q

What is the function of the unique bacterial cytoskeletal protein MinD

A

prevents polymerization of FtsZ at cell poles

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71
Q

What is the function of the unique bacterial cytoskeletal protein ParA

A

Segregates chromosomes and plasmids

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72
Q

The unique bacterial cytoskeletal protein MinD is observed in

A

Many rod-shaped bacteria

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73
Q

The unique bacterial cytoskeletal protein ParA is observed in

A

many species including Vibrio cholerae, C. crescentus, and Thermus themophilus

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74
Q

Microtubule homolog FtsZ is observed in ____ and forms

A

many bacteria and forms ring during septum formation in cell division

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75
Q

Actin homolog MreB is found in ____ and not ___ and maintains

A

found in bacilli and not cocci

maintains shape by positioning peptidoglycan synthesis machinery

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76
Q

Intermediate filament homolog CreS is rare, and maintains

A

curve shape

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77
Q

Inracytoplasmic membranes can be seen as plasma membrane infolding in

A
  • many photosynthetic bacteria

- many bacteria with high respiratory activity

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78
Q

what is Anammoxosome in Plantomycetes

A
  • an Intracytoplasmic Membrane

- An organelle that is the site of anaerobic ammonia oxidation

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79
Q

What are inclusions

A

granules of organic or inorganic material that are stockpiled by the cell for future use

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80
Q

what are some storage inclusions

A
  • Storage of nutrients, metabolic end products, energy, building blocks
  • Glycogen storage
  • Carbon Storage
    • Poly-beta-hydroxybutyrate (PHB)
    • Glycogen
  • Phosphate-Polyphosphate granules (Volutin)
  • Amino Acids- cyanophycin granules
  • Sulfur Granules
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81
Q

Sulphur granules are important in bacteria that don’t use

A

water

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82
Q

Gas vacuoles are found in

A

aquatic, photosynthetic bacteria and archaea

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83
Q

Gas Vacuoles are Aggregates of hollow cylindrical structures called

A

gas vesicles

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84
Q

Function of Gas Vacuoles

A

Provide buoyancy in gas vesicles

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85
Q

Magnetosomes are found in ____ bacteria

A

aquatic

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86
Q

what are the function(s) of magnetosomes

A

magnetite particles (iron) for orientation in Earth’s magnetic field

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87
Q

Cytoskeletal protein ____ helps form magnetosome chain

A

MamK

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88
Q

Microcompartments in bacteria are not bound by membranes but ________ for specific function

A

compartmentalized

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89
Q

What are carboxysomes

A

Microcompartments in CO2 fixing bacteria

- contain the enzyme ribulose-1,5-Bisphosphate carboxylase (Rubisco), enzyme used for CO2 fixation

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90
Q

complex protein/RNA structures that are the sites of protein synthesis

A

Ribosomes

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91
Q

What is the size of bacterial and archaea ribosomes

A

70S

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92
Q

What is the size of Eukaryotic ribosomes

A

80S

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93
Q

What does the S in 80S ribosome stand for

A

Svedburg unit

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94
Q

What are the Bacterial ribosomal RNA subunits

A
  • 16S small subunit

- 23S and 5S in large subunit

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95
Q

The nucleoid of bacteria is usually not _____ bound

A

membrane bound (there are a few exceptions)

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96
Q

____ is the location of chromosome and associated proteins in Bacteria

A

Nucleoid

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97
Q

The nucleoid of bacteria usually 1

A

closed circular, double stranded DNA molecule

98
Q

_____ and ______ (different from histones) aid in folding of DNA in bacteria

A

Supercoiling and nucleoid proteins

99
Q

Characteristics of Prokaryotic Chromosome

A
  • Usually a circular, double-stranded DNA molecule
  • Usually only one
  • Looped and coiled extensively
100
Q

what are plasmids

A
  • extrachromosomal DNA
    • Found in bacteria, archaea, and some fungi
    • usually small, closed circular DNA molecules
  • Exist and replicate independently of chromosome
    • Episomes- may integrate into chromosome
    • inherited during cell division
  • Contain few genes that are non-essential
    • confer selective advantage to host (e.g., drug resistance)
  • Classification based on mode of existence, spread, and function
101
Q

Plasmids are found in

A

bacteria, archaea, and some fungi

102
Q

plasmids exist and replicate _____ of the chromosome

A

independently

103
Q

function of conjugative plasmids

A

Transfer of DNA form one cell to another

104
Q

Example of conjugative plasmids

105
Q

Phenotypic features of conjugative plasmids

A
  • Sex pilus

- Conjugation

106
Q

Hosts for conjugative Plasmids

A
  • E. coli
  • Salmonella
  • Citrobacter
107
Q

What is the function of R plasmids

A

carry antibiotic-resistance genes

108
Q

What is an example of R plasmids

109
Q

What are the hosts of R plasmids

A
  • Pseudomonas

- many other gram-negative bacteria

110
Q

What are the phenotypic features of R plasmids

A
  • Sex pilus
  • Conjugation
  • resistance to Amp, Km, Nm, Tet
111
Q

Function of Col plasmids

A

produce bacteriocins, substances that destroy closely related species

112
Q

host(s) of Col plasmids

113
Q

Phenotypic features of Col Plasmids

A

Colicin E1 production

114
Q

Function of Virulence Plasmids

A

Carry virulence genes

115
Q

Example of Col Plasmids

116
Q

Example of virulence plasmids

117
Q

Hosts of Virulence plasmids

A

-Agrobacterium tumefaciens

118
Q

Phenotypic features of virulence plasmids

A

-Tumor induction in plants

119
Q

Function of metabolic plasmids

A

-carry genes for enzymes

120
Q

Example of metabolic plasmids

121
Q

Hosts of metabolic plasmids

A

Pseudomonas

122
Q

Phenotypic features of Metabolic Plasmids

A

Camphor degradation

123
Q

Rigid structure that lies just outside the cell plasma membrane

A

Peptidoglycan (murein)

124
Q

Stain purple, thick peptidoglycan

A

Gram-Positive Bacteria

125
Q

Stain pink or red; thin peptidoglycan and outer membrane

A

Gram-Negative Bacteria

126
Q

what are the functions of the cell wall

A
  • Maintains shape of the bacterium
    • almost all bacteria have one
  • Helps protect cell from osmotic lysis
  • Helps protect from toxic materials
  • may contribute to pathogenicity
127
Q

Peptidoglycan is a meshlike polymer of identical subunits forming long strands. Two alternating sugars ____ and ___ and alternating ___ and ____ amino acids

A
  • Two alternating sugars
    • N-acetylglucosamine (NAG)
      - N-acetylmuramic acid
    • 4 alternating D- and L- amino acids
128
Q

Chains of peptidoglycan subunits are joined by _______ between the peptides

A

cross-links (covalent bonds)

129
Q

What are the three amino acids found in peptidoglycan that are not found in proteins

A
  • D-glutamic acid
  • D-alanine
  • meso-diaminopimelic acid
130
Q

What is the importance of D-amino acids in peptidoglycan

A

protects against degradation by most peptidases, which recognize only the L-isomers of amino acid residues

131
Q

What are the four amino acids that alternate in the structure of peptidoglycan

A
  • L-Alanine
  • D- Glutamic acid
  • Meso-Diaminopimelic acid
  • D- Alanine
132
Q

The pentapeptide side chain of peptidoglycan terminates with

A

two D-alanines

133
Q

Peptidoglycan strands have a ____ shape

134
Q

Peptidoglycan chains are cross linked by _____ for strength

135
Q

bacteria can cross-link the strands by connecting the carboxyl group of the _____ at position 4 directly to the amino group of _______ (position 3) of the other strand ( the position 5 ______ is removed as the cross-link is formed)

A

D-Alanine, diamiopimelic acid, D-Alanine

136
Q

A peptide interbridge is composed of ____ and goes from ___ of one strand to ___ on the other strand

A

5 glycines, D-alanine, L-lysine

137
Q

Peptidoglycan sacs are _____ networks

A

interconnected

138
Q

Peptidoglycan chains cross-linking is common in

A

Gram-negative bacteria

139
Q

Gram positive cell walls are composed primarily of

A

peptidoglycan

140
Q

Gram positive cell wall are primarily composed of peptidoglycan and may also contain _____

A

teichoic acid (which is negatively charged)

141
Q

What is the function of teichoic acids in the cell walls of gram-positive cell walls

A
  • Helps maintain cell envelope
  • Protect from environmental substances
  • may bind to host cells
142
Q

Do some gram-positive bacteria have layer of proteins on surface of peptidoglycan

143
Q

The periplasmic space of Gram positive bacteria lies between ___ and ____ and is ___ than that of Gram-negative bacteria

A

plasma membrane and cell wall and is smaller than that of Gram negative bacteria

144
Q

The periplasm of gram positive bacteria has relatively few _____

145
Q

Enzymes secreted by Gram-positive bacteria are called

A

exoenzymes

146
Q

Exoenzymes, which are secreted by gram-positive bacteria aid in

A

degradation of large nutrients

147
Q

which has more complex cell walls gram-negative or gram-positive bacteria

A

Gram-negative

148
Q

The cell wall of gram-negative bacteria consists of a ____ layer of peptidoglycan surrounded by an

A

thin layer of peptidoglycan surrounded by an outer membrane

149
Q

The outer membrane of gram-negative cell walls is composed of

A

lipids, lipoproteins, and lipopolysaccharide (LPS)

150
Q

Does the cell wall of gram-negative bacteria have teichoic acids

151
Q

In gram-negative cell walls peptidoglycan is about ______% of cell walls weight

152
Q

The periplasmic space of gram-negative cell walls may constitute ______% of cell volume

153
Q

the periplasmic space of gram-negative cell walls have many enzymes present such as

A

hydrolytic enzymes, transport proteins and other proteins

154
Q

The outer membrane of gram-negative cell walls lays outside the

A

thin peptidoglycan layer

155
Q

_____ connect outer membrane to thin peptidoglycan layer of gram-negative bacteria

A

Braun’s Lipoproteins

156
Q

Lipopolysaccharide (LPS) consists of three parts. What are they

A
  • Lipid A
  • Core polysaccharide
  • O side chain (O antigen)
157
Q

Lipid A is embedded in the

A

outer membrane

158
Q

Core polysaccharide, O side chain extend

A

out from the cell

159
Q

Importance of LPS

A
  • Contributes to negative charge on cell surface
  • Helps stabilize outer membrane structure
  • May contribute to attachment to surfaces and biofilm formation
  • Creates a permeability barrier
  • Protection form host defenses (O antigen)
  • Can act as an endotoxin (Lipid A)
160
Q

What acts as an endotoxin in gram-negative bacteria

161
Q

What is the function of the O antigen in gram-negative bacteria

A

protection from host defenses

162
Q

The Gram-negative outer membrane is more permeable than plasma membrane due to presence of ______ and _____

A

Of porin protein and transporter proteins

163
Q

Porin proteins in the outer membrane of gram-negative bacteria let ______ molecules (_____daltons) pass

A

small (600-700 daltons)

164
Q

Solute concentration outside the cell is less than inside the cell

A

hypotonic environment

165
Q

In a hypotonic environment water moves

A

into the cell and the cell swells

166
Q

The function of the cell wall in a hypotonic environment is that it

A

protects the cell from lysis

167
Q

Solute concentration outside the cell is greater than inside

A

Hypertonic environments

168
Q

In a hypertonic environment water ______ the cell

169
Q

what is plasmolysis

A

when the plasma membrane shrinks but the cell wall remains the same

170
Q

_____ breaks the bond between N-acetyl glucosamine and N-acetylmuramic acid

171
Q

Penicillin inhibits _____ synthesis

A

peptidoglycan

172
Q

Cells that lose a cell wall may survive in _____ environments

173
Q

Mycoplasma does not produce a _____

174
Q

Mycoplasma does not produce a cell wall but their _______ is more resistant to osmotic pressure. Why

A

Plasma membrane. Because it has cholesterol in it

175
Q

examples of cells without cell wall

A
  • Protoplasts
  • spheroplasts
  • Mycoplasma
176
Q

Archaeal cell walls lack peptidoglycan but some have ______ also called ____

A

pseudopeptidoglycan, also called pseudomurein

177
Q

Components outside of the cell wall

A
  • Outermost layer in the cell envelope
  • Glycocalyx
    • capsules and slime layers
    • S layers
  • Aid in attachment to solid surfaces
    • e.g. biofilms in plants and animals
178
Q

Capsules and slime layers aid in attachment to _____

A

solid surfaces

179
Q

Capsules are usually composed of

A

polysaccharides

180
Q

Capsules are well organized and _____ removed form the cell

A

not easily

181
Q

Are capsules visible via light microscope

182
Q

What are the protective advantages of capsules

A
  • Resistant to phagocytosis
  • Protect from desiccation
  • Exclude viruses and detergents
183
Q

Slime layers are similar to capsules except ____, _____ and ____

A

diffuse, unorganized and easily removed

184
Q

Slime layers may aid in

185
Q

S layers are regularly structured layers of ____ or ____ that ____-

A

protein or glycoprotein that self-assemble

186
Q

In gram-negative bacteria the S layer adheres to _____

A

outer membrane

187
Q

In Gram-Positive bacteria the S layer is associated with the ________ surface

A

peptidoglycan surface

188
Q

Functions of S layer

A
  • Protect from ion and pH fluctuations, osmotic stress, enzymes, and predation
  • Maintains shape and rigidity
  • Promotes adhesion to surfaces
  • Protects from host defenses
  • Potential use in nanotechnology
    • S layer spontaneously associates
189
Q

Examples of external structures that extend beyond the cell envelope in bacteria

A
  • Pili and fimbriae

- Flagella

190
Q

Function of external structures that extend beyond the cell envelope in bacteria

A
  • Protection
  • Attachement to surfaces
  • Horizontal gene transfer
  • cell movement
191
Q

short, thin, hairlike, proteinaceous appendages (up to 1,000/cell) that can mediate attachment to surfaces

A

Fimbriae (s. fimbria) ; Pili (s. Pilus)

192
Q

Some (type ____ fimbriae) required for twitching motility or gliding motility that occurs in some bacteria

193
Q

Long, thicker, and less numerous (1-10/cell) and is required for conjugation (mating)

A

sex pili (s. Pilus)

194
Q

Genes for formation of sex pili are found on

195
Q

Threadlike, locomotor appendages extending outward from plasma membrane and cell wall

196
Q

Functions of Flagella

A
  • Motility and swarming behavior
  • Attachment to surfaces
  • May be virulence factors
197
Q

A bacterial flagella has an ultrastructure composed of ____ parts

198
Q

What are the three parts of a bacterial flagella

A
  • Filament
  • Hook
  • Basal body
199
Q

Bacterial flagella are thin, rigid protein structure that cannot be observed with bright-field microscope unless specially

200
Q

The filament of bacterial flagella extends form _____ to the ___

A

cell surface to the tip

201
Q

The filament of bacterial flagella is a ____, ____ cylinder of ______ protein

A

Hollow, rigid cylinder of flagellin protein

202
Q

The hook of bacterial flagella links ____ to ____

A

filament to basal body

203
Q

The basal body of flagella is a series of ___ that _____

A

rings that drive flagellar motor

204
Q

Flagellar synthesis

A
  • Complex process involving many genes/gene products
  • New flagellin molecules transported through the hollow filament using type III-like secretion system
  • Filament subunits self-assemble with help of filament cap at time, not base
205
Q

New flagellin molecules transported through the hollow filament using _____- like secretion system

206
Q

Filament subunits self-assemble with help of _____ at ___, not ___

A

filament cap at tip, not base

207
Q

Monotrichous

A

One flagellum

208
Q

Polar flagellum

A

flagellum at end of cell

209
Q

Amphitrichous

A

one flagellum at each end of cell

210
Q

Lophotrichous

A

cluster of flagella at one or both ends

211
Q

Peritrihous

A

Spread over entire surface of cell

212
Q

bacteria and archaea have direct movement. Name them

A

Directed

  • Flagellar movement
  • Spirochete motility
  • Twitching motility
  • Gliding motility
213
Q

What is movement toward chemical attractants such as nutrients, and away from harmful substances called

A

Chemotaxis

214
Q

Bacteria and archaea move in response to ____, ____, _____, and ___

A

temperature, light, oxygen, osmotic pressure, and gravity

215
Q

In general a bacterial flagellum counterclockwise (CCW) rotation causes _____ motion (run)

216
Q

In general a bacterial flagellum clockwise rotation (CW) causes

A

disrupts run causing cell to stop and tumble

217
Q

____ and ____ create a channel through which protons can flow. This causes the flagellum to rotate

A

MotA and MotB

218
Q

Bacterial flagellum is a ____ part motor producing torque

219
Q

The rotor of the flagellum is composed of _____ and ____, which turn and interact with strator

A

C (FliG protein) ring and MS ring

220
Q

The Strator of a flagellum is composed of _____ and _____ proteins

A

Mot A and Mot B

221
Q

The strator of flagellum form channel through ___

A

plasma membrane

222
Q

Protons move through ____________ using energy of proton motive force

A

Strator (Mot A and Mot B)

223
Q

Torque powers rotation of the _____ and ____

A

basal body and filament

224
Q

Spirochete motility

A
  • Multiple flagella form axial fibril which winds around the cell
  • Flagella remain in periplasmic space inside outer sheath
  • Corkscrew shape exhibits flexing and spinning movements
225
Q

Twitching and Gliding motility may involve _____ and ___-

A

type IV pili and slime

226
Q

Explain twitching motility

A
  • Pili at ends of cell
  • short, intermittent, jerky motions
  • cells are in contact with each other and surface
227
Q

Explain gliding motility

A

smooth movements

228
Q

Movement toward a chemical attractant or away form a chemical repellent

A

chemotaxis

229
Q

changing concentrations of chemical attractants and chemical repellent bind _____ of chemosensing system

A

chemoreceptors

230
Q

in presence of attractant tumbling frequency is _________ and runs in direction of attractant are ____

A

intermittently reduced, longer

231
Q

Behavior of bacterium is altered by _____ concentration of chemical

232
Q

Chemotaxis away from a repellent involves ____ tumbling frequency and run is intermittently ___

A

longer, reduced

233
Q

Complex, dormant structure formed by some bacteria

A

Bacterial endospore

234
Q

Endospores are resistant to

A
  • heat
  • Radiation
  • Chemicals
  • Desiccation
235
Q

Endospore structure is a spore surrounded by thin covering called _____

A

exosporium

236
Q

thick layers of ____ form the spore coat

237
Q

The cortex, beneath the coat of the endospore, is made of ______

A

thick peptidoglycan

238
Q

The core of the endospore has ____ and ___

A

nucleoid and ribosomes

239
Q

What makes an endospore so resistant

A
  • calcium (complexed with dipicolinic acid)
  • Small, acid-soluble, DNA-binding proteins (SASPs)
  • Dehydrated core
  • Spore coat and exosporium protect
  • DNA repair enzymes
240
Q

Process of endospore formation

A

Sporulation

241
Q

Sporulation occurs in

A

hours (up to 10 hours)

242
Q

Sporulation normally commences when growth ___ because of lack of ____

A

ceases, nutrients

Microbiology (16 decks)

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