Topic 4 - Prokaryotic Cell Morphology Part 2 Flashcards
(66 cards)
0
Q
Functions of external structures in bacteria and archaea
A
- Protection
- Attachment to surfaces
- Horizontal gene transfer
- Cell movement
1
Q
Some structures that extend beyond the cell envelope in bacteria and archaea
A
- Fimbriae
- Pili
- Flagella
2
Q
Short, thin, hairlike, proteinaceous appendages (up to 1,000/cell)
A
Fimbriae (s. fimbria)
3
Q
What is the job of fimbriae?
A
- Mediate attachment to surfaces
- Some (type IV fimbriae) required for motility or DNA uptake)
4
Q
- Longer, thicker, and less numerous then fimbriae
A
Sex pili (pl, pilus)
5
Q
Functions of sex pili
A
- Genes for formation found on plasmids
- Required for conjugation
6
Q
Threadlike, locomotor appendages extending outward from plasma membrane and cell wall
A
Flagella
7
Q
Functions of flagella
A
- Motility and swarming behavior
- Attachment to surfaces
- May be virulence factors
8
Q
- Thin, rigid protein structures that cannot be observed with bright-field microscope unless specially stained
- Pattern of flagellation varies
A
Domain Bacteria flagella
9
Q
One flagellum
A
Monotrichous
10
Q
Flagellum at end of cell
A
Polar flagellum
11
Q
One flagellum at each end of cell
A
Amphitrichous
12
Q
Cluster of flagella at one or both ends
A
Lopchotrichous
13
Q
Flagella spread over entire surface of cell
A
Peritrichous
14
Q
Three parts of a flagellum
A
- Filament
- Hook
- Basal body
15
Q
- Extends from surface to the tip of flagellum
- Hollow, rigid cylinder
- Composed of the protein flagellin
- Some bacteria have a sheath around filament
A
Filament
16
Q
The protein that composes the flagellum filament
A
Flagellin
17
Q
- In the flagellum
- Links filament to basal body; made of protein
A
Hook
18
Q
- Series of rings that drive flagellar motor
A
Basal body
19
Q
Explain flagellar synthesis
A
- Complex process involving many genes and proteins
- New flagellin molecules transported through the hollow filament to tip
- Filament subunits self-assemble with help of filament cap at tip, not base
20
Q
Motility in domain Bacteria and Archaea
A
- Flagellar movement
- Spirochete motility
- Twitching motility
- Gliding motility
21
Q
Directed cell movement in response to some stimulus
A
Taxis
22
Q
Move toward chemical attractants such as nutrients, away from harmful substances
A
Chemotaxis
23
Q
Bacteria and Archaea can also move in response to what?
A
Temperature, light, oxygen, osmotic pressure, and gravity
24
Changing concentrations of chemical attractants and chemical repellents does what?
Binds chemoreceptors of chemosensing system
25
- Flagellum rotates like a propeller
| - Very rapid rotation up to 1100 revolutions/sec
Bacterial flagellar movement
26
The two parts of a flagellum
1. Rotor
| 2. Stator
27
How does the rotor in the flagellum work?
C (FliG protein) ring and MS ring turn and interact with stator
28
Mechanic machine made of Mot A or Mot B proteins
Stator
29
How do stators work?
1. Form channel through plasma membrane
2. Protons move through Mot A and Mot B channels using energy of proton motive force
3. Torque powers rotation of the basal body and filament
30
Have corkscrew shape which allows them to move in viscous media
Spriochete Motility
31
How does spirochete motility work?
1. Multiple flagella form axial fibril which winds around the cell
2. Flagella remain in periplasmic space inside outer sheath
3. Corkscrew shape exhibits flexing and spinning movements
32
- Involves contact with surface
| - May involve Type IV pili and slime
Twitching and gliding motility
33
- Pili at ends of cell
- Short, intermittent, jerky motions
- Cells are in contact with each other and surface
Twitching
34
- Smooth movements
Gliding
35
Prokaryotic cytoplasmic structures
- Cytoskeleton
- Intracytoplasmic membranes
- Inclusions
- Ribosomes
- Nucleoid and plasmids
36
Material bounded by the plasmid membrane
Cytoplasm
37
What is the cytoplasm composed of?
- 90-94% water
- Dissolved solutes (ions, sugars, amino acids)
- Somewhat viscous
- Many enzymes and ribosomes
- Cytoskeleton? Cyclosis?
38
Network of fibrous proteins within cytoplasm
The cytoskeleton
39
What is special about the cytoskelton in regards to the different domains?
Homologs of all 3 eukaryotic cytoskeletal elements have been identified in bacteria and 2 in archaea
40
Function of cytoskeleton in things besides eukaryotes
Role in cell division, protein localization, and determination of cell shape
41
Homologs of all 3 eukaryotic cytoskeletal elements have been identified in ____
Bacteria
42
Membrane bound storage structures containing granules of organic or inorganic material that are stockpiled by the cell for future use
Inclusions
43
Some inclusions are enclosed by a ________, but not a _____
- single layer membrane
| - Unit membrane
44
Three facts about inclusions
1. Membranes vary in composition
2. Some made of proteins; others contain lipids
3. May be referred to as microcompartments
45
Storage of nutrients, metabolic end products, energy, building blocks
Storage Inclusions
46
Not bound by membranes but compartmentalized for a specific function
Microcompartments
47
Contain the enzyme ribulose - 1,5,- bisphosphate carboxylase, enzyme used for CO2 fixation
Carboxysomes - CO2 fixing bacteria
48
- Found in aquatic, photosynthetic bacteria and archaea
| - Provide buoyancy in gas vesicles
Gas vacuoles
49
- Found in aquatic bacteria
| - Magnetite particles for orientation in Earth's magnetic field
Magnetosomes
50
What is in the cytoskeleton of magnetosomes and what does it do?
Protein MamK
| - Helps form magnetosome chain
51
Why are ribsomomes complex structures?
- Consist of protein and rRna
| - Site of protein synthesis
52
Complex, dormant structure formed by some bacteria in various locations within the cell
The bacterial endospore
53
What is the function of the bacterial endospore
To survive extreme environments for the organism
54
What environmental conditions are the bacterial endospore resistant to?
- Heat
- Radiation
- Chemicals
- Dessication
55
What does the endospore structure contain?
1. Spore surrounding by thin covering called exosporium
2. Thick layers of protein form the spore coat
3. Cortex, beneath the coat, thick peptidoglycan
4. Core has nucleoid and ribosomes
56
What makes an endospore so resistant?
- Calcium (complexed with dipicolinic acid)
- Small, acid-soluble, DNA-binding proteins (SAPSs)
- Dehydrated core
- Spore coat and exsporium protect
57
- Process of endospore formation
| - Occurs in a few hours (up to 10)
Sporulation
58
When does sporulation commence?
Normally commences when growth ceases because of lack of nutrients, or presence of toxic substances
59
Transformation of endospore into vegetative cell complex, multistage process
Germination
60
Three steps to formation of vegetative cell
1. Activation
2. Germination
3. Outgrowth
61
- Prepares spores for germination
| - Often results from treatments like heating
Activation
62
- Environmental nutrients are detected
- Spore swelling and rupture of absorption of spore coat
- Loss of resistance
- Increased metabolic activity
Germination
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Emergence of vegetative cell
Outgrowth
64
- May exist in many copies in cell
- Inherited stably during cell division
- Curing is the loss of a plasmid
Plasmids
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What is classification of plasmids based on?
Mode of existence, spread, and function
