Chapter 3 Flashcards

(56 cards)

1
Q

morphology

A
  1. cell shape

2. does not predict physiology, ecology, phylogeny of a prokaryotic cell

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2
Q

major cell morphologies

A
  1. coccus
  2. rod
  3. spirillum
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3
Q

coccus

A

spherical or ovoid

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4
Q

rod

A

cylindrical shape

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5
Q

spirillum

A

spiral shape

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6
Q

cells w/ unusual shapes

A

spirochetes, appendaged bacteria, filamentous bacteria

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7
Q

selective forces involved in setting up of morphology

A
  1. optimization for nutrient uptake (small cells w/ high surface to volume ratio)
  2. swimming motility in viscous environments or near surfaces (helical or spiral shaped)
  3. gliding motility (filamentous bacteria)
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8
Q

size range for prokaryotes

A

0.2 micrometers to >700 micrometers in diameter

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9
Q

Rod-shaped bacteria between _______ and _______

A

0.5 and 4.0 micrometer wide, <15 micrometers long

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10
Q

examples of large prokaryotes

A

e. fisheloni, t. namibiensis

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11
Q

size range for eukaryotes

A

10 to >200 micrometers in diameter

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12
Q

advantages to being small

A
  1. small cells have more surface area relative to cell volume than large cells
  2. support greater nutrient exchange per unit cell volume
  3. tend to grow faster than larger cells
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13
Q

lower limits of cell size

A

cellular organisms <0.15 um are unlikely, open oceans tend to contain small cells (0.2-0.4 um in diameter)

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14
Q

cytoplasmic membrane

A
  1. thin structure surrounding cell
  2. vital barrier between cytoplasm and environment
  3. highly selective permeable barrier
  4. enables concentration of metabolites and waste products
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15
Q

composition of membranes

A
  1. phospholipid bilayer
  2. can exist in many chemical forms as a result of variation in groups attached to glycerol backbone
  3. fatty acids point inward to form hydrophobic environment
  4. hydrophilic portions remain exposed to external environment or cytoplasm
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16
Q

cytoplasmic membrane components

A
  1. 6-8 nm wide
  2. embedded proteins
  3. stabilized by h bonds and hydrophobic rxns
  4. mg2+ and ca2+ help stabilize membrane by formation of ionic bonds with negative charges on phospholipids
  5. somewhat fluid
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17
Q

outer surface of plasma membrane can…

A

interact w/ protein that bind substrates OR process large molecules for transport

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18
Q

inner surface of plasma membrane can…

A

interact w/ proteins involved in energy-yielding reactions and other important cellular functions

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19
Q

integral membrane proteins

A

firmly embedded in membrane

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20
Q

peripheral membrane proteins

A

one portion anchored in membrane

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21
Q

membrane strengthening agens

A
  1. sterols

2. hopanoids

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22
Q

sterols

A

rigid, planar lipids found in eukaryotic membranes

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23
Q

hopanoids

A

structurally similar to sterols, present in bacterial membranes

24
Q

cytoplasmic membrane functions

A
  1. permeability barrier (polar and charged molecules must be transported; transport proteins accumulate solutes against concentration gradient)
  2. protein anchor (holds transport proteins in place)
  3. energy conservation
25
3 classes of carrier-mediated transport systems in prokaryotes
1. simple (driven by proton motive force energy) 2. group translocation (chemical modification of transported substance driven by phophoenolpyruvate) 3. ABC system (periplasmic binding) * * ALL REQUIRE PROTEINS AND ENERGY IN SOME FORM (proton motive force or ATP)
26
peptidoglycan
1. rigid layer providing strength to cell wall of bacteria 2. polysaccharide composed of N-acetylglucosamine and acid, amino acids, lysine or DAP, cross-linked differently in gram negative bacteria and gram positive bacteria
27
gram positive cell walls
1. contain up to 90% peptidoglycan 2. common to have teichoic acids embedded in cell wall 3. lipoteichoic acids - teichoic acids covalently bound to membrane lipids
28
prokaryotes lacking cell walls
mycoplasmas (bacteria), thermoplasma (archaea)
29
gram negative cell walls
1. 10% peptidoglycan | 2. most of cell wall composed of outer membrane (LPS layer)
30
LPS
1. consist of core polysaccharide and 0-polysaccharide 2. LPS replaces most of phospholipids in outer half of outer membrane 3. endotoxin - toxic portion of LPS
31
porins
channels for movement of hydrophilic low-molecular weight substances
32
periplasm
1. space located between cytoplasmic and outer membranes 2. 12 nm wide 3. contents have gel-like consistency 4. houses many proteins
33
structural differences between cell walls of gram-positive and gram-negative bacteria are responsible for _______
differences in gram stain rxn
34
archaea cell walls
1. no peptidoglycan 2. no outer membrane 3. pseudomuerin 4. cells walls of some lack pseudomuerin 5. s-layers
35
pseudomuerin
1. polysaccharide similar to peptidoglycan 2. composed of n-acetylglucosamine and acid 3. found in cell calls of methanogic archaea
36
s layers
1. most common cell wall type among archaea 2. consist of protein or glycoprotein 3. paracrystalline structure
37
carbon storage polymers
1. poly-beta0hydroxybutyric acid, lipid | 2. glycogen, glucose polymer
38
polyphosphates
accumulations of inorganic phosphate
39
sulfur globules
composed of elemental sulfur
40
magnetosomes
magnetic storage inclusions
41
gas vesicles
1. confer buoyancy in planktonic cells 2. spindle-shaped, gas-filled structures made of protein 3. gas vesicle impermeable to water
42
endospores
1. highly differentiated cells resitant to heat, harsh chemicals and radiation 2. dormant stage of bacterial life cycle 3. ideal for dispersal via wind, water or animal guy 4. only present in some gram-positive bacteria
43
endospore structure
1. structurally complex 2. contains dipicolinic acid 3. enriched in ca2+ 4. core contains small acid-soluble proteins (SASPs)
44
sporulation process
complex series of events, genetically directed
45
flagellum
1. structure that assists in swimming 2. different arrangements 3. helical in shape
46
flagellar structure
1. consists of several components 2 filament composed of flagellin 3. move by rotation
47
flagellar synthesis
1. several genes required for flagellar synthesis and motility 2. MS ring made first 3. other proteins and hook made next 4. filament grows from tip
48
flagella increase or derease rotational speed in relation to strength of _______
the proton motive force
49
differences in swimming motions
1. peritrichously flagellated cells move slowly in a straight line 2. polarly flagellated cells move more rapidly and typically spin around
50
gliding motility
1. flagella independent 2. slower and smoother than swimming 3. movement occurs along axis odf cell 4. requires surface contact 5. mechanisms: excretion of polysaccharide slime, type IV pili, gliding specific proteins
51
taxes
directed movement in response to chemical or physical gradients
52
chemotaxis
1. response to chemicals 2. best studied in E. coli 3. bacteria respond to temporal, not spatial difference in chemical concentration 4. "run and tumble" behavior 5. attractants and receptors sensed by chemoreceptors
53
phototaxis
response to light
54
aerotaxis
response to oxygen
55
osmotaxis
response to ionic strength
56
hydrotaxis
response to water