CH. 4: Anatomy of Prokaryotic & Eukaryotic Cells Flashcards
1
Q
example of a bacteria that adheres to plastic surfaces using a glycocalyx
A
Serratia
2
Q
prokaryote from greek words for
A
prenucleus
3
Q
eukaryote from greek words for
A
true nucleus
4
Q
PROKARYOTE characteristics:
A
one circular chromosome, NOT in a membrane
no histones
no organelles
binary fission
bacteria: peptidoglycan cell walls
archaea: pseudomurein cell walls
5
Q
EURKARYOTE characteristics:
A
chromosomes in nucleus histones organelles polysaccharide cell walls mitosis
6
Q
prokaryotic cell size
A
0.2-1.0 um x 2-8 um
7
Q
most bacteria are
A
monomorphic (a few are pleomorphic)
8
Q
basic shapes
A
bacillus, coccus, spiral, star-shaped, rectangular
9
Q
bacillus
A
rod-shaped
ie. Bacillus anthracis
10
Q
coccus
A
spherical
ie. Staphylococcus aureus
11
Q
Spiral (3) examples
A
Spirilium – Campylobacter jejuni
Vibrio – Vibrio cholera
Spirochete – Treponema pallidum
12
Q
arrangements (3)
A
pairs, clusters, chains
13
Q
pairs
A
diplo (ie. diplococcic, diplobacilli)
14
Q
clusters
A
staphylococci
15
Q
chains
A
streptococci, streptobacilli
16
Q
Glycocalyx
A
outside cell wall sticky capsule: neatly organized slime layer: unorganized and loose extracellular polysaccharide allows cell to attach capsules prevent phagocytosis can be involved in virulence allows formation of BIOFILMS
17
Q
examples of virulence
A
V. cholerae
B. anthracis
Streptococcus pneumonia
18
Q
flagella located
A
outside cell wall
19
Q
flagella made of
A
chains of FLAGELLIN
20
Q
flagella attached TO
A
a protein hook
21
Q
flagella anchored to the wall/membrane via
A
the basal body
22
Q
GRAM POSITIVE bacteria
A
only one membrane layer (thicker peptido)
23
Q
GRAM NEGATIVE bacteria
A
plasma membrane, thinner peptido, AND outer membrane
24
Q
flagella type: peritrichous or polar
A
distributed over the entire cell (peritrichous) or at one or both ends/poles of the cell (polar)
25
monotrichous and polar
single flagellum at one pole
26
lophotrichous and polar
a tuft of flagella coming from one pole
27
amphitrichous and polar
flagella at both poles of the cell
28
motile cells
rotate flagella to run or tumble
| move toward or away from stimuli (TAXIS)
29
flagella PROTEINS are
H antigens
| e.g.: E.coli O157:H7
30
axial filaments
aka endoflagella
in spirochetes (axial filaments wrap around spirochetes)
anchored at one end of a cell
rotation causes cell to move
31
fimbrae allow
attachement
32
pili (functions)
facilitate transfer of DNA from one cell to another
| & motility (Gliding motility & Twitching motility)
33
cell wall main function
prevents osmotic lysis
34
lysis =
disintegration of a cell by rupture of the cell wall or membrane
35
cell wall maintains
shape, flagellum anchorage
36
cell wall made of
peptidoglycan (in bacteria) aka murein
37
clinical importance of cell wall:
target for antibiotics
38
peptidoglycan: polymer of disaccharide
NAG (N-acetylglucosamine) & NAM (N-acetylmuramic acid)
39
bacteria in gram + bacteria linked by
polypeptides
| -- various structures (always have tetrapeptide side chains**)
40
gram + cell wall
thick peptido
TEICHOIC ACIDS
may regulate movement of cations
polysaccharides provide antigenic variation
41
(gram +) lipotechoic acid links to
plasma membrane
42
(gram +) wall techoic acid links to
peptidoglycan
43
gram negative cell wall
thin peptido
outer membrane
PERIPLASMIC space
44
gram negative OUTER membrane
- - lipopolysaccharides (LPS), lipoproteins, phospholipids
- - forms the periplasm between the outer membrane and the plasma membrane (location of thin peptido layer, contains degradative enzymes and transport proteins)
- - PROTECTION from PHAGOCYTES, COMPLEMET, and ANTIBIOTICS
- - PORINS (proteins) form channels through membrane
45
LPS (lipopolysaccharides) in gram negative OUTER membrane composed of 3 components:
1. core polysaccharide
2. O Polysaccharide antigen, e.g.: E.Coli O157:H7
3. Lipid A is an ENDOTOXIN
46
gram stain mechanism:
crystal violet-iodine crystals form in cell
47
gram positive via gram stain:
alcohol dehydrates peptidoglycan
| CV-I crystals do not leave; they retain the crystal violet stain
48
gram negative via gram stain:
alcohol dissolves outer membrane and leaves holes in peptidogylcan
-- CV-I washes out
49
Safranin counterstain shows only in
gram negative cells
| because the darker colour of the CVI crystals masks it in gram positive cells
50
(staining) if cell walls are degraded, then
gram positive cells will show as gram-negative
51
bacteria examples that are gram variable
Bacillus
| Clostridium
52
(atypical cell walls) acid-fast cell walls
- -waxy lipid (mycolic acid) bound to peptidoglycan (prevents gram stain dye uptake)
- - ie. Mycobacterium, Nocardia
- - dyed with carbolfuchsin which penetrates the cell wall and binds to cytoplasm
- - cells retain colour following washing with acid-alcohol because carbolfuchsin is more soluble in the mycolic acid than in the acid-alcohol
53
(atypical cell walls) mycoplasmas
lack cell walls
- - sterols in plasma membrane
ie. Mycobacterium tuberculosis
54
(atypical cell walls) archaea
wall-less, or
| walls of pseudomurein (lack NAM and D-amino acids)
55
(damage to cell wall)
| Lysozyme digests
disaccharide in peptidoglycan
56
(damage to cell wall)
| penicillin inhibits
peptide bridges in peptidoglycan
57
Protoplast
a wall-less cell
58
Speroplast
a gram-negative cell with its outer membrane damaged
59
protoplasts and speroplasts are susceptible to
osmotic lysis
60
L forms are
wall-less cells that swell into irregular shapes (can return to a walled state)
61
osmotic lysis
bursting of a cell due to excess influx of extracellular fluid which the membrane/wall cannot accommodate
62
the plasma membrane
- phospholipid bilayer
- peripheral proteins
- integral proteins
- transmembrane proteins
63
fluid mosaic model
- membrane is as viscous as olive oil
- proteins move to function
- phospholipis rotate and move laterally
64
the plasma membrane
- selective permeability allows passage of some molecules
- enzymes for ATP production
- photosynthetic pigments
- target
- damage to the membrane by alcohols, quaternary ammonium (disinfectants) and polymyxin antibiotics causes leakage of cell contents (if you've managed to already destroy the cell wall, this is a second tactic you take)
65
target for antimicrobial action is
the plasma membrane
66
photosynthetic pigments of the plasma membrane located
on foldings called chromatophores or thylakoids
67
simple diffusion:
movement of a solute from an area of high concentration to an area of low concentration
68
facilitated diffusion:
solute combines with a transporter protein in the membrane (high to low areas, cell does not use energy) ie/ for water, simple sugars, vitamins, ions.
69
osmosis:
move't of water across a selectively permeable membrane from an area of high to low concentration
70
osmotic pressure:
the pressure needed to stop the movement of water across the membrane
71
water can move through the plasma membrane via (2)
the lipid layer
| aquaporins (water channels)
72
isotonic solutions
no net move't of water occurs
73
hypotonic solutions
water moves INTO the cell
if the cell wall is strong, it can contain the swelling
if the cell wall is weak/damaged, the cell bursts (OSMOTIC LYSIS)
74
hypertonic solution
water moves OUT of the cell
causes its cytoplasm to shrink
can cause PLASMOLYSIS
75
active transport:
requires a transporter protein and ATP
- - against the conc. gradient
- - used for ions, amino acids and simple sugars
76
group translocation:
- - requires a transporter protein and phosphoenolpyruvic acid PEP
- - exclusive to prokaryotes
- - keeps modified compound in the cell
In group translocation, a special form of active transport that occurs exclusively in prokaryotes, the substance is chemically altered during transport across the membrane. Once the substance is altered and inside the cell, the plasma membrane is impermeable to it, so it remains inside the cell. This important mechanism enables a cell to accumulate various substances even though they may be in low concentrations outside the cell.
77
cytoplasm
the substance inside the plasma membrane
78
the nucleoid
bacterial chromosome
79
plasmids
- circular prokaryotic DNA that is separate from the nucleoid
- can have one to many
- size of plasmid can vary
- they can be shared by both the same and different species through a process involving conjugation of the pili
- antibiotic resistance and virulence factors are often acquired in this way
80
the PROkaryotic ribosome
protein synthesis
70S (50S + 30S subunits)
SMALLER AND LESS DENSE THAN EUKARYOTIC RIBOS.
--> differences allow for antibiotic targeting (e.g. streptomycin
81
inclusions
reserve deposits within the cytoplasm of prokaryotic cells
- - may help reduce osmotic pressure
- - can serve as a basis for identification
82
```
[inclusions]
Metachromatic granules (volutin)
```
phosphate reserves
| -- characteristic of Corynebacterium diptheriae, the causative agent of diphtheria
83
[inclusions]
| polysaccharide granules
energy reserves
84
[inclusions]
| lipid inclusions
energy reserves
85
[inclusions]
| sulfur granules
energy reserves
86
[inclusions]
| carboxysomes
Ribulose 1,5-diphosphate carboxylase
| for CO2 fixation
87
[inclusions]
| gas vacuoles
protein-covered cylinders
88
[inclusions]
| magnetosomes
iron oxide (destroys H2O2)
89
endospores
- resting cells
- formed by GRAM POSITIVE cells under NUTRIENT POOR conditions
- RESISTANT to dessication, heat, chemicals
90
examples that form endospores
Bacillus, Clostridium
91
Sporulation:
endospore formation
92
Germination:
return to vegetative state
93
one gram negative species that can produce endospore like structures
Coxiella burnetti
94
flagella and cilia
- - contain cytoplasm
- - microtubules (Tubulin and 9 pairs + 2 array)
- - movement is different than prokaryotic flagella
95
cell wall in
plants, algae, fungi
| carbohydrates (composition)
96
cell wall composition can be of
cellulose, chitin, glucan, mannan
97
protozoa have an outer protein covering called
a pellicle (they have no cell wall)
98
glycocalyx
carbohydrates extending from an animal plasma membrane
| bonded to proteins and lipids in membrane
99
eukaryotic plasma membrane
```
phospholipid bilayre
peripheral proteins
integral proteins
transmembrane proteins
sterols
glycocalyx carbohydrates
```
100
sterols do what?
help prevent lysis
101
eukaryotic plasma membrane functions
simple and facilitative diffusion, osmosis, active transport
endocytosis*
102
endocytosis
1. phagocytosis: pseudopods extend and engulf particles
2. pinocytosis: membrane folds inward, bringing in fluid and dissolved substance
3. receptor-mediated: binding results in inward folding of the membrane (can bring in viruses)
103
cytoplasm membrane:
substance inside plasma and outside nucleus
104
cytosol:
fluid portion of cytoplasm
105
cytoskeleton:
microfilaments, intermediate filaments, microtubules
106
cytoplasmic streaming:
movement of cytoplasm throughout cells
107
eukaryotic ribosomes
protein synthesis
* 80S (60S/40S subunits)
- membrane bound: attached to ER
- free: in cytoplasm
* 70S
- in chloroplasts and mitochondria
108
nucleus
contains chromosomes
109
ER
transport network
110
golgi complex
membrane formation and secretion
111
lysosome
digestive enzymes
112
vacuole
brings food into cells and provides suport
113
mitochondrion
cellular respiration (matrix)
114
chloroplast
photosynthesis (granum -- made up of thylakoids)
115
peroxisome
oxidation of fatty acids; destroys H202
116
centrosome
consists of protein fibers and centrioles
117
endosymbiotic theory
According to the endosymbiotic theory, eukaryotic cells evolved from symbiotic prokaryotes living inside other prokaryotic cells.
118
evidence for endosymbiotic theory:
- size and shape of chloroplasts and MITOCHONDRIA
- ribosomes
- DNA
- mechanisms of protein synthesis
- effects of antibiotics
119
3 organelles associated with the golgi complex:
1. peroxisomes
2. mitochondria
3. lysosomes
120
flagella are much more ___ in eukaryotic cells
complex
121
prokaryotes do not have ____
cilia
