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Microbio > Bacteria and Archaea (3, 4, 5) > Flashcards

Bacteria and Archaea (3, 4, 5) Flashcards

1
Q

Bacterial cells: components outside cell wall

A

Have ONE of the following:
- slime layers
- capsules
- s-layers (proteins)
Protection, some movement, some adhesion

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2
Q

Capsules

A
  • usually composed of polysaccharides
  • well-organized and not easily removed from cell
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3
Q

slime layer

A
  • diffuse, unorganized, easy to remove
  • motility: helps cells glide
  • biofilms: community of microorganisms, work together
    • waste from one might fuel another
    • example: dental plaque
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4
Q

s-layers

A
  • protect from ions and pH fluctuations, osmotic stress
  • maintains shape and rigidity
  • adhesion
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5
Q

cytoplasmic structures

A
  • cytoplasm
    • ribosomes
    • nucleoid
    • plasmids
    • cytoskeletal proteins
    • inclusions
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6
Q

cytoskeletal proteins: functions

A

similar to those in eukaryotes
- cell division
- protein location and movement
- cell shape

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7
Q

FtsZ: homologue and function

A
  • found in many bacteria and archaea
  • homologue of tubulin (type of microtubule)
  • cell division
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8
Q

MreB: homologue and function

A
  • found in many rods and some archaea
  • homologue of actin (type of microfilament)
  • maintains cell shape
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9
Q

CreS: homologue and function

A
  • found in vibrio bacteria
  • homologue of keratin
  • creates comma shape by building up and inhibiting an area
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10
Q

common storage units: names and functions

A
  • poly-B-hydroxybutyrate (PHB) granules: carbon storage
  • polyphosphate granules: store phosphate
  • sulfur globules: store sulfur
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11
Q

microcompartments: names and functions

A
  • carboxysomes: carbon fixation (CO2 into fuel)
    • found in cyanobacteria
  • gas vacuoles: store gas for buoyancy
    • found in aquatic photosynthetic bacteria
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12
Q

Ribosomes in archaea and bacteria

A
  • type 70s
    • svedberg unit
  • antibiotics target ribosomes
  • since svedberg unit is different in bacteria than in eukaryotic cells, the antibiotics only impact bacterial cells
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13
Q

nucleoid region

A
  • irregularly-shaped
  • usually not membrane-bound
  • usually one chromosome
  • circular, double-stranded DNA
  • nucleoid-associated proteins (NAPS): coil DNA
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14
Q

plasmids

A
  • extrachromosomal DNA
    • found in bacteria and archaea
    • usually small, circular, closed DNA molecules
  • exist and replicate independently of chromosome
  • contain few genes that are non-essential but are of advantage to the organism
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15
Q

plasmids: 5 examples

A
  1. conjugative plasmids: transfer DNA from one cell to another
  2. R-plasmids: antibiotic resistance genes
  3. col plasmids: produce bacterioncins, which can kill other similar species
  4. virulence plasmids: carry virulence genes and cause disease
  5. metabolic plasmids: carry genes for enzymes, degradation
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16
Q

external structures: functions

A
  • protection
  • surface attachment
  • cell movement/motility
  • horizontal gene transfer
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17
Q

pili and fimbria: structure and function

A
  • short, thin, hair-like appendages
  • most mediate attachment to surfaces
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18
Q

Type IV pili

A

motility

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19
Q

Sex pili

A

conjugation

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20
Q

flagella: structure and function

A
  • threadlike, locomotor appendages
  • motility and attachment
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21
Q

patterns of flagella distribution

A
  1. monotrichous: polar flagellum, single, rod-shaped
  2. amphitrichous: one on both end
  3. lophotrichous: tuft
  4. peritrichous: surrounding cell
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22
Q

flagella: 3 parts

A
  1. filament
    - extends from cell surface to tip
    - hollow, rigid structure
    - composed of flagellin protein (some have sheath)
  2. hook
    - links filament to basal body
  3. basal body
    - intrecellular
    - flagellar motor
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23
Q

motility in archaea and bacteria

A
  • directed movement
  • chemotaxis
    • move in response to stimuli: temperature, light, oxygen, osmotic pressure, gravity
    • go to nutrients, away from danger, etc.
  • not all are motile
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24
Q

flagellar movement: 5 types

A

most common
1. swimming
2. swarming
other
3. spirochete
4. twitching
5. gliding

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25
flagellar movement: swimming
- flagellum rotates like a propellor - rapid (1100 revolutions/second) - counterclockwise: run - clockwise: tumble - detecting clues, chemotaxis "check-in" - proton motive force: gradient
26
Peritrichous flagella: swimming
run: form bundle and all rotate same direction tumble: alternate rotational direction (every other flagella)
27
flagellar movement: swarming
- usually peritrichous - multiple cells group together - form distinctive growth patterns
28
flagellar movement: spirochete
- multiple flagella form axial fibril, which winds around cell - endoflagellum - corkscrew shape exhibits flexing and spinning forces
29
flagellar movement: twitching
- type IV pili - short, intermittent, jerky motions
30
flagellar movement: gliding
- slime (ATP or neck proteins) - smooth movement
31
bacterial endospore
- complex, dormant structure formed by some bacteria - various locations - resistant to numerous environmental conditions - heat - radiation - chemicals
32
bacterial endospore: structure
1. core: DNA and ribosomes 2. inner membrane: like plasma membrane 3. core wall: peptidoglycan 4. cortex: peptidoglycan 5. outer membrane 6. coat: protection layer 7. exosporium
33
sporulation (endospores): 7-step process
- takes ~10 hours 1. axial filament formation: DNA condenses to one side 2. septum formation, forespore development: one side of cell walls off into a smaller compartment 3. engulfment of forespore: mother cell "eats" forespore, creating multiple layers 4. cortex formation: cortex develops 5. coat synthesis: protein 6. maturation process 7. lysis of sporangeum: loses mother cell
34
poly-B-hydroxybutyrate granules (PHB)
- storage inclusion - store carbon
35
polyphosphate granules
- storage inclusion - store phosphate
36
sulfur globules
- storage inclusion - store sulfur
37
carboxysomes
- microcompartment - found in cyanobacteria - carbon fixation: CO2 into fuel
38
Gas vacuoles
- microcompartment - store gas for buoyancy - found in aquatic, photosynthetic bacteria
39
plasmids
- extrachromosomal DNA - found in bacteria and archaea - small, closed circular DNA molecules - exist and replicate independently of chromosome - contain few non-essential genes that are of advantage to organism
40
conjugative plasmids
- transfer DNA from one cell to another
41
R-plasmids
- antibiotic resistance genes
42
Col plasmids
- produce bacteriocins, which can kill other similar species
43
virulence plasmids
- carry virulence genes, cause disease
44
metabolic plasmids
- carry genes for enzymes, degradation
45
3 parts of flagella
1. filament: extends from cell surface to tip - hollow, rigid - composed of flagellin protein - some have sheath 2. hook - connect filament to basal body 3. basal body - intracellular - flagellar movement
46
formation of vegetative cells
1. activation 2. germination: environmental nutrients detected, spore swelling/rupture/absorption, increased metabolic activity 3. outgrowth
47
Archaea: similarities with eukarya
- replication, transcription, translation, & the proteins/enzymes involved in these processes
48
Archaea: similarities with bacteria
- metabolism
49
Archaea: size and shape
- commonly found as cocci and rods - can be bottle, square, elongated rod, tear, vibrio - 0.1-1.5 microns in size
50
archaeal cell envelope vs bacterial cell envelope
- archaeal doesn't have peptidoglycan - some have pseudomurein (sugar layer) - some have s-layer - capsules and slime membranes are rare
51
archaeal plasma membrane
composed of unique lipids - branched hydrocarbons - ether linkages (unlike ester in bacteria) - stereochemistry differences - some form monolayers (rather than bilayers like bacteria)
52
archaeal cell walls
- lack peptidoglycan - may contain pseudomurein
53
archaea: cell wall types
1. s-layer canopies 2. protein sheath, s-layer 3. s-layer, pseudomurein (like gram +) 4. polysaccharide (like gram +) 5. double membrane (like gram -)
54
archaea: cytoplasm
similar to bacteria - similar components - ribosomes, nucleoid - FtsZ
55
archaea: nucleoid
- irregularly shaped - usually not membrane bound - double stranded, circular - nucleoid proteins (NAPS) aid in supercoiling
56
archaeal flagella: differences from bacteria
- thinner - more than one type of flagellin protein - not hollow
57
archaea: pili types
cannulae: cell-cell communication hami: like a grappling hook
58
archaeal DNA replication: similarities to eukarya
helicases, DNA polymerase
59
archaeal DNA replication: similarities to bacteria
- circular chromosome - plasmids - bidirectional
60
archaeal transcription: similarities to eukarya
eukarya-like transcription machinery - DNA polymerase - TATA box-binding protein - TFB - similar elongation factors
61
archaeal transcription: similarities to bacteria
regulation of transcription - transcription regulators - 70s ribosomes
62
selenocysteine
- coded for by UGA - protects from oxidative damage
63
pyrrolysine
- coded for by UAG - methanogenic characteristics
64
archaea: protein secretion
- sec system - tat system (unique to bacteria and archaea) - can transport folded proteins
65
archaeal metabolism: 3 pathways
1. emden-meyerhof pathways (glycolysis) 2. 2 modified entner-doudoroff pathways
66
archaeal metabolism: lacks
- pyruvatedehydrogenase complex - pyruvate oxidoreductase - some lack TCA (krebs, citric acid cycle)
67
thermostability of archaea
- chaperones - reverse DNA gyrase - makes DNA more stable - 2003 discovery of strain 121 - goegemma barossii, can withstand 121 degrees C
68
archaeal taxonomy
- 16 proposed phyla - 2 genera - sulfolobus - thermoproteas - 5 physiological groups
69
genus sulfolobus
- irregularly-lobed - aerobic - thermoacidophiles - 70-80 degrees celsius - pH 2-3 - specialized ABC transporters
70
genus thermoproteus
- long, thin rods - anaerobic - thermoacidophiles - 75-100 degrees celsius - pH 3-4 - reductive TCA cycle (reverse: CO2 + ATP-> acetyl coA - acetyl coA: makes fats, ATP, ADH - can be catabolized or used anabolically
71
5 major physiological groups of archaea
- methanogens - haloarchaea - thermoplasms - extreme thermophile - sulfur-reducing archaea
72
methanogens
- produce methane from CO2 via methanogenesis - rods, cocci, curved rods, irregular - unusual metabolism
73
haloarchaea
- aerobic - cubes, pyramids, rods, cocci - high salt requirements - requires at least 1.5 M NaCl - growth optima near 3.4 M NaCl - red to yellow pigment
74
thermoplasms
- thermoacidophiles lacking cell wall - thermoplasma: 59 degrees C, pH 1-2 - picrophilus: 47-65 degrees C, can grow at pH zero
75
extreme thermophile
- motile by multiple flagella - 88-100 degrees C - strictly anaerobic
76
sulfur-reducing archaea
- irregular cocci cells - anaerobes - optimum 83 degrees C - reduce sulfate to sulfide
77
uptake of nutrients: passive diffusion
doesn't need transport proteins
78
uptake of nutrients: facilitated diffusion
needs carrier protein
79
active transport
- requires energy - ATP - goes against concentration gradient - group translocation - primary and secondary active transport
80
primary active transport
- uses solute-binding proteins - unmodified solute - uses ATP to pull it in
81
secondary active transport
- uses ion gradients - no modification - cotransporter - symporter: 2 things in - antiporter: 1 in, 1 out
82
group translocation
- PEP (phosphenyl pyruvate) as energy - modification: phosphorylation - low to high concentration - phosphenol pyruvate: sugar phosphotransferase system (PTS) - phosphorelay: one molecule passes phosphate to the next
83
key players in phosphorelay
1. PEP 2. Enzyme I 3. HPr 4. Enzyme II A 5. Enzyme II B (phosphate stays here) 6. Enzyme II C (conformational change so glucose can enter and become phosphorylated) End: glucose-6-phosphate or mannitol-1-phosphate
84
iron uptake
- complex transported into cells - siderophore: binds to iron and moves into cell
85
culture media
solid or liquid medium used to grow, transport, and store microbes - must contain all nutrients required for the organism to grow - agar, broth
86
culture media: supportive
- many microorganisms - tryptic soy agar
87
culture media: enriched
- fastidious microorganisms with specific nutritional needs ex: blood agar - B-hemolytic colony - different levels of hemolysis - beta: most breakdown, alpha: partial breakdown, gamma: growth w/out breakdown
88
culture media: selective
- favors growth of some microorganisms and inhibits growth of others ex: MacConkey agar: lactose fermenters vs. non-fermenters ex: mannitol salt: selects gram +, differentiates mannitol perm
89
Isolation of pure culture
- population of cells arising from single cell - isolate colony in sterile media - spread & streak plate
90
streak plate
- mixed culture on a plate - each cell can form a separate colony - use single colony to create pure culture - divide plate into quadrants, drag sample to each area - spread evenly with sterile bent rod
91
reproductive strategies
- binary fission (most bacteria) - budding - multiple fission - spore formation
92
binary fission steps
1. cell elongates while chromosome replicates 2. septum forms (FtsZ needed) 3. new peptidoglycan between cells 4. separation
93
multiple fission
- within cell envelope - progyny forms
94
spore formation
forms filaments
95
halotolerant
salinity of up to 3 M
96
halophile
salinity between 0.2-3.5 M
97
extreme halophile
salinity between 2-6 M
98
acidophile
pH 0-5.5
99
neutrophile
pH 5.5-8
100
alkalophile
pH 8-11.5
101
microbes and temperature
- microbes cannot regulate their internal temperature - enzymes have optimal temperature requirements
102
psychrophiles
0-20 degrees C
103
psychrotrophs
0-35 degrees C
104
mesophiles
20-45 degrees C
105
thermophiles
45-85 degrees C
106
hyperthermophiles
70-105 degrees C
107
obligate anaerobe
- cannot grow in presence of oxygen - grow at bottom of tube
108
obligate aerobe
- need oxygen to grow - grow at top of tube
109
microaerophiles
- need a little bit of oxygen - grow close to top
110
facultative anaerobes
- capable of growing in either condition - start with oxygen but can switch to fermentation if needed
111
aerotolerant anaerobes
- can grow under any condition
112
microbes and pressure
- microbes on land/water surface live at 1 atm - some live deep in sea at 600-1100 atm
113
barotolerant
can live at high hydrostatic pressure
114
barophilic
must live at high hydrostatic pressure
115
bacterial cell cycle: steps
- chromosome replication and partitioning - cytokineses
116
chromosome replication and partitioning
- replicates bidirectionally from origin - replisome (machinery involved in DNA replication) - terminus
117
cytokinesis
- separation - selection of site for septum formation - z-ring assembled, cell wall synthesizing machinery - constriction of cell
118
z-ring assembly
- protein FtsZ - MinCDE directs FtsZ: inhibits it from forming in regions where MinCDE is present
119
cell growth
- determined by peptidoglycan synthesis - UDP and bactoprenols - MurJ flippase, glycosyltransferase, transpeptidase
120
UDP
- part of cell growth - collects NAG and NAM and brings it to bactoprenol
121
bactoprenol
- part of cell growth - collects NAG and NAM and brings to MurJ
122
MurJ flippase
- part of cell growth - flips NAG and NAM to periplasmic side
123
geogemma barossii
- strain 121 - can withstand 121 degrees celsius
124
picrophilus
- thermophile that can grow at pH zero
125
glycosyltransferase (GT)
links NAG and NAM together during cell growth
126
transpeptidase (TP)
links NAM together during cell growth
127
growth curve stages
1. lag 2. exponential 3. stationary 4. death 5. long-term stationary
128
lag phase
taking in nutrients and preparing for binary fission
129
exponential phase
binary fission
130
stationary phase
- plateau - threshold reached - waste buildup, need for O2
131
death phase
- natural selection - some cells can withstand toxic levels

Microbio (11 decks)

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