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Microbiology > Bacteria and Archaea Structure, Function, and Nutrition > Flashcards

Bacteria and Archaea Structure, Function, and Nutrition Flashcards

1
Q

Pili: what are they, and what is their purpose

A

Thin, protein appendages on outside of bacteria

Used for attachment

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2
Q

Sex pili: purpose

A

Used for conjugation (form of horizontal gene transfer)

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3
Q

Type IV pili: purpose

A

Twitching motility (cycles of extension, attachment, and retraction)

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4
Q

Monotrichous

A

One flagellum

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5
Q

Polar flagellum

A

Flagellum at end of cell

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6
Q

Amphitrichous

A

One flagellum at each end of cell

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7
Q

Lophotrichous

A

Cluster of flagella at one or both ends of cell

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8
Q

Peritrichous

A

Flagella spread over entire surface of cell

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9
Q

3 parts of flagella

A

Basal body
Hook
Filament

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10
Q

Basal body components

A

Rod and series of rings
Rod and bottom ring turn, but L and P rings don’t
L and P rings stabilize

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11
Q

Basal body acts as what for flagella?

A

Motor

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12
Q

Source of energy for basal body rotation

A

Proton motive force (charge gradient)

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13
Q

Hook features

A

Flexible

Attached to basal body

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14
Q

Filament extends from what structure?

A

Hook

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15
Q

Are basal body, hook, and filament hollow or solid? What are they made out of?

A

Hollow

Protein

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16
Q

Counterclockwise rotation of flagellum causes what type of motion?

A

Forward motion (run)

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17
Q

Clockwise rotation of flagellum causes what type of motion?

A

Disruption of run: cell stops and tumbles

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18
Q

How many revolutions per second can flagellum rotate?

A

1100 revolutions/second

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19
Q

Chemoreceptors

A

Allow cell to sense different environmental conditions

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20
Q

Chemotaxis

A

Sensory system that enables microbes to move toward or away from specific chemicals

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21
Q

Attractants

A

Bacteria travel toward these

Nutrients

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22
Q

Repellants

A

Bacteria travel away from these

Toxins

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23
Q

Attractants cause what type of flagellar rotation?

A

Counterclockwise rotation (run)

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24
Q

In E. coli, which are peritrichously flagellated, how does running work?

A

Flagella bundle is formed near pole, which enables running

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25
Repellants cause what type of flagellar rotation?
Clockwise rotation (tumble and direction change)
26
In E. coli, which are peritrichously flagellated, what happens when running bacteria are exposed to repellants?
Flagella fly apart (flagella bundle dissolves)
27
Runs + tumbles = ?
Random walk
28
Random walk occurs when?
No attractants are present
29
How does bacterial movement change when exposed to an attractant gradient?
Chemoreceptors detect attractant Counterclockwise rotation is favored Runs become longer and tumbles less frequent
30
Biased random walk
Net movement up attraction gradient
31
Are archaea prokaryotic or eukaryotic?
Prokaryotic
32
How do archaea reproduce?
Asexually
33
What habitats are archaea found in?
Terrestrial and aquatic
34
What type of chromosomes do archaea have? Do they have plasmids?
Circular, dsDNA chromosomes | Archaea have plasmids
35
Does Gram positive and negative apply to archaea? Do they come in different shapes?
Archaea can be gram positive or negative | Diverse shapes
36
What scale are archaea measured on?
Micrometers
37
Do archaea have plasma membranes?
Yes
38
Do archaea have cell walls? Are they made of peptidoglycan?
Some have cell walls, but no peptidoglycan
39
Archaea that lack cell walls: what replaces?
S-layers
40
Can archaea have flagella?
Yes
41
Methanogenesis
Unique to archaea | Biological production of methane (CH4)
42
Methane: what is it, and where is it found?
Potent greenhouse gas | Found in ruminants of cattle (contain archaea)
43
Extremophiles
Archaea that can grow in conditions that would normally kill microbes
44
Thermophiles: what temperatures can they grow at?
Between 45 and 85 degrees C
45
Hyperthermophiles: what temperatures can they grow at?
Between 85 and 113 degrees C
46
Strain 121
Archaea that can grow in autoclave (121 degrees C)
47
Haloquadratum
Archaea that can grow in high salt environment (shaped like 4 postage stamps together in a square shape)
48
Similarities between archaeal and bacterial lipids and membranes
``` 2 hydrophilic surfaces with 1 hydrophobic surface Bilayer membrane (only with C20 diethers in archaea) ```
49
Differences between archaeal and bacterial lipids and membranes
Ether linkages to glycerol in archaea rather than ester linkages in bacteria Archaea have isoprene (5 carbon) units as hydrocarbons Monolayers in archaea with C40 tetraethers
50
Archaeal membranes provide what advantage for growing in high temperature environments?
Enhanced stability
51
Pyrococcus furiosus: what type of archaea is it, what is its nickname, how many flagella does it have, and what does it produce?
Hyperthermophile "Rushing fireball" More than 50 flagella Source of Pfu polymerase for PCR
52
To obtain energy and construct new cellular components, microbes must have a supply of what two things?
Raw materials | Nutrients
53
Nutrients
Substances used in biosynthesis and energy release | Required for growth
54
Macronutrients/ macroelements: what are they and what elements are considered to be these?
Required by microbes in large amounts | P, O, N, C, H, S, Fe (Remember "PONCHOS" plus Fe)
55
Micronutrients/ trace elements: what are they and what elements are considered to be these?
Required by microbes in small amounts | Co, Cu, Zn, Mn
56
What sources of nitrogen do bacteria use?
Ammonia (NH3), nitrate (NO3), or nitrogen gas (N2)
57
Nitrogen fixation: what is it, and what 2 types of bacteria do it?
N2 is reduced to NH3 | Rhizobium (in symbiosis with plants in root nodules) and Azotobacter (free living in soil)
58
Food must enter at what rates, across what, in what type of fashion, and against what?
High rates Across membranes Selective fashion Often against concentration gradient
59
Passive transport: is energy required? If not, what is required?
Energy is not required | Requires gradient from higher to lower concentrations
60
Passive diffusion
No carrier molecules needed | Only small molecules and certain gases
61
Facilitated diffusion
Uses membrane carrier proteins that undergo conformation change Example: aquaporins form H2O channels
62
Passive vs facilitated diffusion rates
Passive diffusion: same rate at high and low levels of nutrient (straight line on graph) Facilitated diffusion: higher rate at low level of nutrient, plateaus at high level of nutrient as carrier proteins are saturated (log curve on graph)
63
Active transport: is energy required? If so, where does energy come from? What does it do?
Energy is required ATP or proton motive force used Moving nutrients against gradient
64
2 types of active transport
Primary and secondary
65
ABC transporters: what does ABC stand for, and what type of transporters are they?
ATP-binding cassettes | Primary active transport
66
Steps of primary active transport (ABC transporters)
1. Solute binds to solute binding protein 2. Solute binding protein plus solute triggers conformational change in transporter, catalyzed by ATP hydrolysis 3. Solute is released and transported by transporter across membrane
67
Uptake ABC: function
Move nutrients in to cell
68
Export ABC: function and alternate name
Move substances out of cell | Also called multidrug efflux pumps
69
What export ABCs move out in bacteria, and what that does for the cell
Export ABCs can move antibiotics out of bacterial cells, rendering them antibiotic resistant
70
What export ABCs move out in cancer cells, and what that does for the cell
Export ABCs can move anti-cancer drugs out of tumor cells, rendering them drug resistant
71
Secondary active transport: energy source
Potential energy of ion gradients (proton motive force)
72
How is proton gradient generated
Electron transport across membranes
73
Lac permease: what type of transport, what does it move
Secondary active transport (symport) | Moves lactose and proton in same direction (into cell)
74
Group translocation: phosphotransferase system
Sugars (nutrients) are chemically altered prior to transportation into bacterial cell Energy from phosphoenolpyruvate (PEP) attaches phosphate group to sugars
75
What pathway is phosphoenolpyruvate (PEP) an intermediate of?
Glycolysis (conversion of glucose to pyruvate)
76
Siderophores: what problem do they solve for bacteria?
Little free iron is available in bacterial environments, so siderophores bind iron Siderophore-Fe complex can be transported into cell (often using ABC transporters)

Microbiology (24 decks)

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