Chapter 3-Cell Structure of Prokaryotes Flashcards
1
Q
How do Prokaryotes differ from Eukaryotes?
A
in size and simplicity
2
Q
most prokaryotes lack a _____________
A
internal membrane system
3
Q
prokaryotes are divided into _____________
A
bacteria and archaea
4
Q
describes cell shape
A
morphology
5
Q
what are the 3 major cell morphologies? (there are variations from the main 3)
A
coccus (cocci), bacillus (bacilli), spirillium
6
Q
2 cocci
A
diplococcus
7
Q
chains of cocci
A
streptococcus
8
Q
4 cocci
A
tetrad
9
Q
8 cocci
A
sarcinae
10
Q
many cocci
A
staphylococcus
11
Q
diplobacilli
A
2 bacilli
12
Q
chains of bacilli
A
streptobacilli
13
Q
several parallel cells along long axis
A
pallisade
14
Q
rods
A
bacilli
15
Q
very short rods
A
coccobacilli
16
Q
resemble rods, comma shaped
A
vibrios
17
Q
rigid helices
A
spirilla
18
Q
flexible helices
A
spirochetes
19
Q
network of long, multinucleate filamentous cells
A
mycelium
20
Q
organisms that are variable in shape
A
pleomorphic
21
Q
Why is it advantageous for a cell to be small?
A
small cells have a higher SA to volume ratio than large cells, allows for greater nutrient exchange per unit of cell volume
22
Q
what makes up the cell envelope?
A
(1) structures exterior to the cell wall
(2) cell wall
(3) cell membrane
23
Q
What are the functions of the cell membrane?
A
maintain cell integrity, regulate transport, protein attachment, receptors for detection of/response to chemicals in surroundings, energy metabolism in prokaryotes
24
Q
describes the cell membrane as somewhat fluid, somewhat solid, lipid bilayer with floating proteins
A
fluid mosaic model
25
phospholipid bilayer with proteins, no sterols, but contains hopanoids (both hydrophobic and hydrophilic components), many variations to glycerol backbone
composition of cytoplasmic membrane
26
loosely connected membrane protein on cytoplasmic side, easily removed
peripheral protein
27
embedded with membrane, project outward and inward, amphipathic, control important functions and microdomains
integral proteins
28
completely cross membrane
transmembrane protein
29
What are two cell membrane strengthening agents?
(1) sterols
| (2) hopanoids
30
rigid and planar, found in eukaryotic membranes, strengthen membrane, only found in a very few prokaryotes
sterols
31
structurally similar to sterols, present in membranes of many Bacteria
hopanoids
32
liquid crystal, rigid and temperature dependent
cell membrane
33
What happens when the cell membrane gets too cold?
solidification occurs, gelling, Van der Waals forces pull tails together
34
What happens when the cell membrane gets too warm?
thermal lysis, cell death
35
How is the correct fluidity of a cell membrane obtained?
adjust fatty acid composition
if cold: more unsaturated fatty acids, minimize VDW forces
if hot: more saturated fatty acids, minimize VDW forces
36
transport which does not require ATP or other cellular energy to be used by the cell
passive transport
37
transport which require the cell to extend its own energy in the form of ATP
active transport
38
transport that doesn't require a transport protein
simple transport
39
transport which requires a transport protein
facilitated transport
40
the movement of a molecule due to inherent kinetic energy from high concentration to low concentration
diffusion
41
the diffusion of water across a membrane
osmosis
42
What are the factors that determine transport across a cell membrane?
(1) Charge of the molecule
(2) Size of the molecule
(3) Shape of the molecule
43
What are the factors that determine movement across a cell membrane?
non-polar or small polar between phospholipids, all ions and all polar substances allowed through transport protein
44
ligand binds specific proteins, slow saturation effect, highly specific
receptor mediated transport systems
45
simultaneous transport and chemical modification of transported substance
group translocation
46
exterior to cell membrane, rigid and mostly structural polysaccharide and peptide/protein, prevent osmotic lysis in colonial prokaryotes
cell wall
47
pressure from water entering the cell, causes a rupture of the cell membrane and death of the cell
osmotic lysis
48
solute concentration outside is less that inside, water moves into cell and cell swells, cell wall protects from lysis
hypotonic environment
49
solute concentration outside the cell is greater, water leaves the cell, plasmolysis occurs
hypertonic environment
50
What will happen to a cell wall in hypotonic solution if no lysozyme or penicillin is present?
the cell will lyse
51
protoplasts are ___________
gram positive
52
spheroplasts are ____________
gram negative
53
purple stain, thick layer of peptidoglycan
gram positive
54
pink or red stain, thin peptidoglycan
gram negative
55
the structural polysaccharide in the cell walls of domain Bacteria prokaryotes, mesh like polymer of identical sub units forming long strands, 2 alternating sugars, alternating D & L amino acids
peptidoglycan
56
peptidoglycan strands have a ________shape, and are cross-linked by ____________
(1) helical
| (2) covalent bonds
57
almost 90% peptidoglycan, have large amounts of teichoric acid (maintain cell envelope, bind to host cell, attract cations) may have layer of proteins on surface
gram positive cell wall
58
thin layer of peptidoglycan, outer membrane composed of phospholipids, lipoproteins, and lipopolysaccharide, Braun's lipoprotein crosses from outer membrane to peptidoglycan
gram negative cell wall
59
have 3 parts (lipid A, a core polysaccharide, and an O side chain), place negative charge on cell surface, stabilize outer membrane structures, helps to create a permeability barrier, protects from host defenses
lipopolysaccharides
60
a gram negative outer membrane is more permeable than a plasma protein due to the presence of ____________ and ___________
porin proteins and transfer proteins (allow small molecules to pass)
61
polysaccharide rich material exterior to the cell wall, has multiple protein components
glycocalyx
62
a dense, tightly attached, regular arrangement of polysaccharides that sits exterior to the cell wall, visible to a light microscope, most are gram +
capsule
63
a diffuse, loosely attached irregular arrangement of polysaccharides, attach to solid surfaces and prevent virus attachment
slime layer
64
regularly structured layers of protein and glycoprotein that self assemble, gram (-) adhere to outer membrane, gram (+) associate with peptidoglycan surface
s-layers
65
What are the functions to the s-layer?
(1) protect from ion/pH/osmotic pressure
(2) maintain shape and rigidity
(3) promote adhesion to surfaces
(4) protect from host defenses
66
short, thin, hairlike proteinaceous appendages that mediate attachment to surfaces
fimbriae and pili
67
similar to fimbriae but longer, thicker and less numerous, genes for formation found on plasmids
sex pili
68
threadlike locomotor appendages that extend outward from plasma membrane, attach to surfaces and provide motility and a swarming behavior
flagella
69
one flagellum
monotrichous
70
flagellum at end of cell
polar flagellum
71
one flagellum at each end of cell
amphitrichous
72
cluster of flagella at one or both ends
lophotrichous
73
spread over entire surface of cell
peritrichous
74
What are the three parts of flagella?
(1) filament
(2) hook
(3) basal body
75
part of flagella, extends from cell surface to the tip, a hollow and rigid cylinder, composed of the protein flagellin
filament
76
part of flagella, links filament to basal body, made of protein
hook
77
part of flagella, series of rings that drive flagella motor
basal body
78
directed cell movement in response to some stimulus
taxis
79
movement toward chemical attractants such as nutrients and away from harmful substances
chemotaxis
80
a flagellum rotates like a ______________
propeller
81
Spirochetes have a ____________ shape which allows for movement in a viscous media.
corkscrew
82
a movement described as short, intermittent jerky motions
twitching
83
moving in smooth motion and movement
gliding
84
material bound by the plasmid membrane, 95% water, dissolved solutes, contains cytoskeleton, enzymes and ribosomes
cytoplasm
85
network of fibrous proteins within the cytoplasm, important in cell division and determine cell shape
cytoskeleton
86
What are two types of intracytoplasmic membranes?
(1) cell membrane infoldings
| (2) anammozosome in planctomycetes
87
membrane bound storage structures containing granules of in/organic material that are stockpiled by the cell for future use, glycogen and carbon storage, amino acids and other nutrients
inclusions
88
not bound by membranes but compartmentalized for a specific function (CO2 fixing bacteria)
microcompartments
89
an inclusion found in aquatic, photosynthetic bacteria and archaea, provide buoyancy in gas vesicles
gas vacuoles
90
found in aquatic bacteria, orientate themselves based on the Earth's magnetic field, help make protein
magnetosomes
91
have a complex structure, site of protein synthesis, larger in eukaryotes than bacteria
ribosomes
92
archaeal __________ are more similar to eukarya than bacteria
ribosomes
93
no nucleus, no membrane around DNA, found in an irregularly shaped region, 10-15% of cytoplasmic volume, DNA is circular and supercoiled
nucleoid
94
extrachromosomal DNA, found in bacteria, archaea and some fungi, small closer, circular DNA molecules, exist and replicate independently of chromosome, exist in many copies within cell, contain four genes that are non-essential
plasmids
95
complex, dormant structure formed by some bacteria, function is to survive extreme environments for organism, resistance to numerous environmental conditions (heat, radiation, chemicals)
bacterial endospore
96
thick covering of exosporium, and spore coat make up the ____________
endospore structure
97
process of endospore formation, occurs in only a few hours, ends when growth ceases b/c of lack of nutrients, complex, multistage process
sporulation
98
How is an endospore resistant?
calcium (complex with acid), small, acid soluble DNA binding proteins, spore coat and exosporium to protect
99
a multistage process that transforms an endospore into a vegetative cell complex
germination
100
prepares spores for germination, often results from treatments like heating
activation formation of a vegetative cell
101
occurs when environmental nutrients are detected, spore swelling and rupture of spore coat, loss of resistance, increased metabolic activity
germination formation of vegetative cell
