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microbio > lecture 3 and 4 > Flashcards

lecture 3 and 4 Flashcards

1
Q

what does Cooci look like? Bacilli? Vibros, spirilla, spirochetes, and pleomorphic?

A

Vibrios - curved/comma shaped
Spirilla - rigid spiral-shaped
Spirochetes - flexible spiral-shaped
Pleomorphic - organisms that are variable in shape
Cocci - single or arranged spheres
Bacilli - rods

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2
Q

What are some common bacterial features?

A

Cell envelope
plasma membrane
cell wall

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3
Q

Cell envelope?

A

the plasma membrane and all of the surrounding layers external to it

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4
Q

Plasma membrane

A
  • innermost membrane that encompasses the cytoplasm
  • selectively permeable barrier
  • Interacts with the external environment (can respond to external stimuli)
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5
Q

Bacterial lipids:

A
  • The plasma membrane is a thin structure mostly composed of a lipid bilayer - amphipathic lipids
  • Hopaniods - hydrophobic molecules similar to cholesterol (impacts fluidity and shape and forms functional microdomains for protein assembly)
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6
Q

Cell wall
- purpose?

A
  • maintain shapes, protects cells from toxic materials and osmotic lysis
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7
Q

Peptidoglycan
- another name?
- what is it

A
  • (murein) - rigid mesh structure lying outside the plasma membrane
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8
Q

what does the cross-linking mean for peptidoglycan and what are the two types?
- what does it alternate?

A
  • The stands have a helical shape and are crosslinked for strength
  • Direct cross-link - between amino and carboxyl groups
  • Indirect cross link - peptide interbridge may form
  • NAG and NAM - alternating sugars
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9
Q

what color does gram-positive stain?
- what kind of membrane?
- peptidoglycan?
- may contain?

A
  • purple
  • it is a monoderm (single membrane) that is only made up of peptidoglycan (thick)
  • teichoic acids and periplasm (not important for +)
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10
Q

what are teichoic acids?

A
  • negatively charged
  • These make sure to maintain the cell envelope
  • Protect from environmental substances
  • May bind to host cells to initiate infection
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11
Q

what color do gram-negative stain?
- what type of membrane? peptidoglycan?

A
  • pink or. red
  • Diderm (2 membrane)
  • A small layer of peptidoglycan
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12
Q

why are gram negatives more complex than gram positives?

A
  • No teichoic acids
  • Outer membrane outside thin peptidoglycan layer, connected to peptidoglycan and has made of lipids, lipoproteins, and lipopolysaccharide
  • Periplasmic space may make up 20-40% of the volume
  • contains proteins, LPS,q and enzymes
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13
Q

what purpose does the periplasmic space have in gram negatives? Is Gram positive?

A
  • gram +: no importance
  • gram -: has two checkpoints in the outer membrane and transports to the cytoplasm (fact check)
    `
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14
Q

LPS - lipospolysaccarides

A
  • contribute to a negative charge on the surface
  • Helps stabilize the outer membrane
  • Host defense protection
  • Acts as endotoxin
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15
Q

what are the components outside the cell wall?

A

capsules
slime layers
S layer
bacterial cytoplasm

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16
Q

what are capsules?

A
  • like a jacket
  • Are well organized and cannot be easily removed from the cell
  • Usually composed of polysaccharides
  • Protective function - resistant to phagocytosis, protects from desiccation, and excludes viruses and detergent
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17
Q

what are slime layers?

A

Similar to capsules but they diffuse, unorganised, and easily removed
May facilitate motility
- Cheap version (like vasleine instead of jacket)

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18
Q

S (surface layer)

A
  • Regularly structures self-assembling layers of protein or glycoprotein
  • Protect from ion/pH fluctuations, osmotic stress, enzymes, predation, host defense - these are only in cells with extreme environments
  • Maintains shape and rigidity
  • Promotes adhesion to surface
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19
Q

bacterial cytoskelton
gas vacuoles

A
  • Bacterial cytoskeleton
    Protein filaments that participate in cell division, localize proteins, and maintain cell shape
  • Gas vacuoles:
    Involved in bacterial movement
    Provide buoyancy to aquatic bacteria
    Made of aggregates of hollow, cylindrical gas vesicles
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20
Q

ribsomes?

A

Complex protein/RNA structure
Sites of protein synthesis

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21
Q

Nucleoid

A

Usually not membrane-bound
- Usually 1 closed circular ds DNA molecule/chromosome

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22
Q

plasmid

A

Small, closed, circular, independent DNA molecules
Carry genes that can confer a selective advantage in some situations

23
Q

what are the external structures of bacteria? what do they do and look like?

A
  • fimbriae/pili
  • sex pilli
  • flagella
24
Q

what are fimbira/pili?

A

Short thin hair-like, protein appendages
Can mediate attachment to surfaces, motility, and DNA uptake

25
Q

sex pili?

A

Longer, thicker, less numerous
Required for conjugation
More defined hollow and produces genetic variation

26
Q

Flagella
function and what it looks like?

A
  • Threadlike, locomotor appendage extending outward from the plasma membrane and cell wall
  • motility, attachment to surface, virulence factor (causes disease)
27
Q

what is flagella structure made up of?

A

filament /flagellum - extends from cell surface to top
Hook - short flexible segment
Basal body - embedded in cell envelope

28
Q

what is the two-part motor-producing technique?

A
  • Rotor - moving parts, C-ring ring interact with stators and connects to the rod
  • Stator- stationary parts, capture PMF through the membrane to generate torque and drive rotation
29
Q

what are two ways that flagella can move?

A
  • rotates like a propeller
    CCW rotation = forward movement
    CW disrupts run = tumble
30
Q

how can flagella move?

A
  • chemotaxis: movement towards a chemical attraction or away from chemical repellant
  • Chemoreceptors transmit signals throughout the chemosensing system - detect external signals and determine whether it should run or tumble
31
Q

swarming?

A
  • long collective run togetehr (lot together)
  • Cells move faster than swimmers and have increased resistance to antibiotics
32
Q

what are the three ways tthat bacteria will move based on non-flagellum moves?

A
  • Twitching motility
    Type IV Pili at ends of the cell
    Short jerky motions
    Cells are in contact with each other and the surface
  • Gliding
    Smooth movements without appendage
    Slime may aid movement on the surface
  • Spirochete motility
    Flagella remain inside the cell wall, winding around the cell
    Corkscrew shape exhibits flexing and spinning movements
33
Q

endospores

A

Complex, dormant structure formed by some bacteria
Form in response to nutrient depletion
Spores are resistant to numerous environmental conditions

34
Q

how does archaea differ from bacteria?

A
  • some lack cell walls
  • The slime layer is used to mediate cell-to-cell interactions
  • s-layer is standard used
35
Q

the common shape of archaea?

A

-cocci and rod shape

36
Q

what does an archaea membrane look like?

A
  • unique lipids - that are branched chains of hydrocarbons attached to a glycerol by ether linkage
  • eukarya and bacteria are connected by esters
37
Q

what is the difference between archea and bacterias cytoplasm?

A
  • A ribosomes have different nuc sequences so which means the protein composition is different (makes them unaffected by antibiotics attacking ribosomes)
  • more similar to Euk
38
Q

what are the two types of pilli? archaea

A
  • cannulae - hollow tube structure (how daughter cells are connected to each other)
  • hami - looks like a grappling hook
39
Q

three characteristics of Archaea flagella?

A
  • thinner than bacteria - not hollow
  • powered by ATP hydrolysis
  • direction moves the cell forward or backward
40
Q

what is EUK plasma membrane made up of?

A

sphingolipids
sterols
phospholipids (hydrophobic fatty acids)

40
Q

Two types of euk? charachteristics?

A
  • protist and fungi
  • common in ecosystems
  • adapts
  • larger than A and B
  • major human pathogen
41
Q

EUK
cytosol?
ribsomes?

A
  • liquids where organelles are located
  • larger than B and A, bound to ER
42
Q

EUK
cytoskeleton (3 types of filaments)

A
  • helps organize cytoplasm
  • cell shape/motor proteins associated with filaments that guide cell movements
    1. actin - small (helps shape)
    2. microtubules - thin (spindles)
    3. intermediate - flexible and structural
43
Q

EUK
nucleus
nuclear envelope

A
  • chromones, chromatin (complex of DNA and proteins)
  • 2 lipid bilayer that surrounds nuc and pores allows the material to be transported in or out of nuc
44
Q

hydrogenosome (euk)

A
  • small energy capture organelles in some anerobic porteist
  • ATP us made by fermination
45
Q

EUK flagella and cillia

A
  • long whiplike and move in undulating fashion
  • short hair like structures and beat with 2 phases
46
Q

virus
- virons?
- nucleocapsids?

A
  • mature virus
  • made up of nucleic acids (DNA or RNA and a protein coat (capsid)
47
Q

2 broad types of virus?

A
  1. non-evloped (naked)
  2. enveloped - has a lipid membrane
48
Q

viral envelope?

A
  • a flexible membraneous layer of lipids and carbs
  • can have spikes or peplomers on their surface
  • can be used to identify a virus
49
Q

one step growth curve?
(4 steps)

A
  • uses radioactively labeled T4 and E. Coli
    1. virus binds to cells
    2. eclipse : virion penetrates the cells (no growth)
    3. burst: The host cell releases as many particles as possible
    4. burst size: number virions released per bacterium
50
Q

viral multiplication steps (5)

A
  1. Attachment : to host cell receptor
  2. entry
    - fusion of viral envelope with host cells plasma membrane
    - endocytosis
    - release of nucleic acids (puncture and inject)
  3. synthesis of viral porteins and nucleic acids
  4. assembly
  5. virons released (2 ways)
    - host cell lysis (nonevloped used)
    - release by budding
51
Q

virulent phage vs temperate phage

A
  • v: multiples and will be released by lyses
  • temperate: 2 reproductive options, reproduces lytically
  • ## can remain in hist cell without destroying it
52
Q

lyses vs lysogeny

A
  • lyses: enters >replicates>leaves
  • lysogeny: inserts>intergrates into host chromsome> replicats so stays dorminant until exposure stresses it > leaves
53
Q

how are viruses cultured and quanitified?

A
  • can not be cultures
  • dilution of virus smples, number of plaques counted and results are in PFU

microbio (5 decks)

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