Chapter 3 Flashcards
(226 cards)
1
Q
what does the small cell size do for prokarytic cells?
A
high surface area to low volume
* Facilitates rapid uptake of nutrients, excretion of wastes
* Allows rapid growth
2
Q
what are the disadvantages of Prokaryotic cells
A
vulnerability to threats including
predators, parasites, and competitors
3
Q
what does the large size of Eukaryotic cells do for it
A
many cellular processes take
place in membrane-bound compartments
4
Q
(visible light) can magnify 1,000x
Common, important tool in microbiology
A
Light microscope
5
Q
can magnify more than 100,000x
fine details
A
Electron microscope
6
Q
can produce images of individual atoms on a surface
A
Atomic force microscope
7
Q
Light passes through specimen and then series of
A
magnifying lenses
8
Q
is most common type of microscope
Evenly illuminates the filed of view and generates a bright
background
A
Bright-field microscope
9
Q
a selection of lens options provides different magnifications. the total magnification is the product of the magnifying power of the ocular lens and the what lens
A
objective lens
10
Q
controls the brightness of the light
A
rheostat
11
Q
controls the amount of light that enters the objective lens
A
iris diaphragm lever
12
Q
focuses the light
A
condenser lens
13
Q
magnifies the image, usually 10-fold (10x)
A
ocular lens (eye piece)
14
Q
apparent increase in size
A
Magnification
15
Q
two types of lens in modern compound microscopes
A
objective
16
Q
microscope objective lens powers
A
4x, 10x, 40x, and 100x
17
Q
magnification power of ocular lens
A
10x
18
Q
between light source and specimen
A
Condenser lens
19
Q
focuses light on specimen, does not magnify
A
Condenser lens
20
Q
resolving power, or ability to distinguish two objects that are very close together
A
Resolution
21
Q
minimum distance between two points at which those points can be observed as separate
A
Resolution
22
Q
what does resolution depend on
A
quality and type of lens, wavelength of light
magnification
specimen preparation
23
Q
Maximum resolving power of light microscope is
A
0.2 micrometer
24
Q
what is used for maximum resolution?
A
immersion oil
25
is used to displace air
between lens and specimen when using high powered 100x
objective
immersion oil
26
measure of speed of light passing
through medium
refractive index
27
bending of light ray
refraction
28
Refractive index of glass is different from what but similar to what
different from air but similar to oil
29
determines how easily cells can be seen
Contrast
30
do stains kill microbes?
yes
31
- Cells appear bright against a dark background
- Directs light toward specimen at angle
- Only light scattered by specimen enters objective lens
Dark-Field Microscope
32
- Special optics amplify difference between refractive
index of dense material and surrounding medium
- Makes cells and other dense material appear darker
Phase-Contrast Microscope
33
- Like phase-contrast, has special optics that depend
upon differences in refractive index
- Separates light into two beams that pass through
specimen and recombine
- Light waves are out of
phase when recombined,
yield three-dimensional
appearance of image
Differential Interference Contrast (DIC) Microscope
34
- Cells or materials either naturally fluorescent or tagged
with fluorescent dyes
- Molecules absorb light at one wavelength (usually
ultraviolet light) and emit light at longer wavelength
Fluorescence Microscopes
35
UV light projected onto, not
through, specimen
epifluorescent
36
- Allows detailed interior views of intact cells
- May provide 3-D images of thick cells
- Specimens usually stained with fluorescent dye
- Fluorescent tags bind to certain internal compounds
- Marks their location
Scanning Laser Microscopes (SLM)
37
- Uses a laser beam to illuminate a point
- Mirrors scan laser beam across specimen, illuminating
successive planes
– Each plane represents one fine slice of specimen; Computer
constructs 3-D image
– Like a miniature computerized axial tomography (CAT) scan
for cells
Confocal Microscopes
38
- low energy used
- Less damaging to cells; allows time-lapse images
- Give interior views of relatively thick structures
Two-photon Microscope
39
- Can magnify images 100,000x
- One drawback is that lenses and specimen must be in vacuum
- Air molecules would interfere with electrons
- Results in large, expensive
unit and complex specimen
preparation
Electron microscopy
40
wavelength of electrons
~1,000 shorter than light
* Resolving power ~1,000-fold
greater: ~0.3 nm
41
two types of Electron microscopy
Scanning Electron Microscope (SEM)
Transmission Electron
Microscope (TEM)
42
- Beam of electrons pass through or scatter
- Depends on density of region: dark areas dense
- Thin-sectioning used to view fine
internal details, but process can
distort cells
Transmission Electron
Microscope (TEM)
43
- Used to observe surface details
- Surface coated with thin film of metal
* Beam of electrons is scanned over surface
* Electrons released from specimen are observed
* Yields 3-D effect
Scanning Electron Microscope (SEM)
44
types of Scanning Probe Microscopes
Atomic Force Microscopes (AFM)
45
- Detailed images of surfaces
- Resolving power much greater than that of EM
- Avoid special preparation required for EM
- Sharp probe moves across
sample’s surface
- Feels bumps, valleys of atoms
- Laser measures motion,
computer produces surface map
Atomic Force Microscopes (AFM)
46
uses a drop of liquid specimen
Wet mount
47
downsides of wet mount
can be difficult to see when colorless
48
what kind of cells are in wet mount
Live cells
49
drying and fixing specimen before staining to visualize
smear
50
involves one dye
Simple staining
51
what kind of dyes carry positive charge
Basic
52
what kinds of dyes carry negative charge and can be used
on wet mounts
Acidic dyes
53
used to distinguish different
types of bacteria
Differential staining
54
types of Differential staining
Gram stain
Acid-fast staining
55
most common stain for bacteria
Gram stain
56
Two groups of Gram stain
Gram-positive, Gram-negative
57
what color does violet and iodine turn the cells
purple
58
what color does alcohol turn the cells
gram-positive = purple
gram-negative = colorless
59
what color does safranin turn the cells
gram-positive = purple
gram-negative = pink
60
used to detect organisms that do not readily take up dyes
Acid-fast staining
61
special stains
capsule stain
endospore stain
flagella stain
62
a staining procedure used to detect specific cell structures
special stains
63
- Some microbes surrounded by gel-like layer (for protection)
- Stains poorly, so negative stain often used
- India ink added to wet mount is common method
Capsule stain
64
- Members of genera including Bacillus, Clostridium
form resistant, dormant endospore
- Resists Gram stain, often appears as clear object
- Endospore stain uses heat to facilitate uptake of the
primary dye malachite green by endospore
- Counterstain (usually safranin) used to visualize other cells
Endospore stain
65
- Too thin to be seen with light microscope
- coats flagella to thicken and make visible
- Presence and distribution can help in identification
Flagella stain
66
uses fluorescent dye attached
to an antibody to tag unique microbe protein
Immunofluorescence
67
two most common Prokaryotic Cell's shapes
Coccus
Rod
68
spherical
Coccus
69
cylindrical
Rod
70
other prokaryotic cell's shapes
Vibrio
spirillum
spirochete
Pleomorphic
71
shapes of bacteria
Coccus
Bacillus
Vibrio
Spirillum
Spirochete
Pleomorphic
72
Spherical cells, may be flattened
on one end or slightly oval.
coccus
73
A rod shaped, cylindrical cell
Bacillus
74
A short, curved rod.
vibrio
75
A curved rod long enough to
form spirals.
spirillum
76
- form swarms of cells that glide over moist
surfaces as a pack
- Collectively release enzymes and degrade organic
material, including other bacterial cells
Myxobacteria
77
A long, spiral-shaped
cell with a flexible cell wall and a unique mechanism of
motility.
Spirochete
78
Refers to bacteria that characteristically
vary in their shape.
Pleomorphic
79
Most prokaryotes divide by what
binary fission
80
type of cell groupings
chains
packets
clusters
81
cell divides in one plane
chains
82
cells divides in two or more planes perpendicular to each other
packets
83
defines boundary of cell
Cytoplasmic membrane
84
Hydrophobic tails face where
in
85
hydrophilic heads faces where
out
86
Proteins serve numerous functions
* Selective gates
* Sensors of environmental conditions
* Fluid mosaic mode
87
proteins drift about in lipid bilayer
Fluid mosaic model
88
have same general structure of
cytoplasmic membranes
Bacteria and Archaea
89
is selectively permeable
Cytoplasmic membrane
90
what passes freely through Cytoplasmic membrane
O2, CO2, N2, small hydrophobic molecules
91
Other molecules must be moved across membrane via
transport systems
92
Free movement of molecules in and out of the cell through the phospholipid bilayer
Simple Diffusion
93
what is the movement for simple diffusiom
high to low concentration
94
Diffusion of water across
selectively permeable
membrane due to
unequal solute
concentrations
osmosis
95
a solution with a high concentration of solutes relative to water, or to a state of having too much muscle tone.
Hypertonic
96
as a lower concentration of solute than another solution, meaning water will flow out of it
Hypotonic
97
having the same concentration of water and solutes as a cell
isotonic
98
a series of protein complex embedded in the cytoplasmic membrane
Electron Transport Chain
99
Use energy from electrons to move protons out of cell
Electron Transport Chain
100
energy that Electron Transport Chain uses
proton motive force
101
to move nutrients and other small
molecules across the cytoplasmic membrane
transport systems
102
things that transport systems use
Transporters, permeases or carriers
103
move waste products and other toxic substances out of cell
efflux pumps
104
is a form of passive transport
Facilitated diffusion
105
how does Facilitated diffusion move
Movement down gradient; no energy required
106
requires energy
Active transport
107
what movement does Active transport do
Movement against gradient
108
two mechanisms of Active transport
- proton motive force
- Use ATP (ABC transporter)
109
Chemically alter compound
Group Translocation
110
examples of Group Translocation
Glucose
111
active movement out of cell
Protein secretion
112
example of Protein secretion
exoenzymes
113
(extracellular enzymes)
exoenzymes
114
Proteins tagged for secretion via
signal sequence
115
is strong, rigid
structure that prevents cell
lysis
Cell wall
116
two main types of bacteria
* Gram-positive
* Gram-negative
117
color of gram staining for Gram-positive
purple
118
color of gram staining for Gram-negative
pink
119
types of gram positive
bacillus
staphyloccoccus
streptococcus
120
types of gram-negative
escherichia, neisseria, pseudomonas
121
has porin proteins
gram negative
122
Cell wall is made from
peptidoglycan
123
Alternating series of subunits
form
glycan chains
124
types of glycan chains
N-acetylmuramic acid (NAM)
* N-acetylglucosamine (NAG)
125
string of
four amino acids
Tetrapeptide chain
126
links glycan
chains
Tetrapeptide chain
127
Tetrapeptide chain links glycan
chains in gram-negative
Direct link
128
Tetrapeptide chain links glycan
chains in gram-positive
Peptide interbridge
129
has thick peptidoglycan layer
The Gram-Positive Cell Wall
130
lies below peptidoglycan layer
periplasm
131
has thin peptidoglycan layer
Gram-negative
cell wall
132
what is unique about Gram-negative cell wall
outer membrane
133
what is Gram-Negative Cell Wall outermembrane made from
Bilayer made from lipopolysaccharide (LPS)
134
how are Gram-Negative Cell important medically
signals immune system of invasion
by Gram-negative bacteria
135
another name for lipopolysaccharide (LPS)
endotoxin
136
blocks passage of many molecules including certain antibiotics
Outer membrane
137
Small molecules and ions can cross via
porins
138
Between cytoplasmic membrane and outer membrane is
periplasmic space
139
what is Periplasm filled with and why
proteins because exported proteins
accumulate unless specifically moved across outer
membrane
140
Can weaken to point where unable to prevent cell lysis
Peptidoglycan
141
interferes with peptidoglycan synthesis by Preventing cross-linking of adjacent glycan chains
Penicillin
142
is Penicillin more effective against Gram-positive bacteria or
Gram-negative bacteria
Gram-positive
143
breaks bonds linking glycan chain by Destroying structural integrity of peptidoglycan molecule
Lysozyme
144
is Lysozyme more effective against Gram-positive bacteria or
Gram-negative bacteria
Gram-positive
145
have a thick peptidoglycan layer as their primary cell wall component
gram-positive bacteria
146
have a thin peptidoglycan layer covered by an additional outer membrane, making them more resistant to antibiotics due to this extra barrier
gram-negative bacteria
147
do notes on graph on slide 59
148
bacteria that lack a cell wall
Mycoplasma
Penicillin
Lysozyme
149
have variety of cell walls
Archaea
150
have variety of cell walls
Archaea
151
do Archaea have peptidoglycan
no
152
what molecule does archaea have that is similar to peptidoglycan
pseudopeptidoglycan
153
other type of bacteria that has no cell wall
microbacteria
154
Gel-like layer outside cell wall that protects or allows attachment to surface
capsules and slime layers
155
distinct, gelatinous
capsule
156
diffuse, irregular
Slime layer
157
Allow bacteria to adhere to
surfaces
capsules and slime layers
158
allow bacteria to evade host immune system
capsules
159
unique type of dormant cell
Endospores
160
what kind of layers does archaea have
S-layers
161
Extremely resistant to heat, desiccation, chemicals, ultraviolet light, boiling water
Endospores
162
Endospores that survive can
germinate to become
vegetative cell
163
formation of endospores
▪ Sporulation
164
what is Sporulation triggered by
triggered by
carbon or nitrogen limitation
165
how long does it take for sporulation to complete
8 hours
166
maintains core in dehydrated state, protects from
heat
cotex
167
has small proteins that bind and protect DNA
Core
168
what is Germination triggered by
heat, chemical exposure
169
how long does germination take
1-2 hours
170
involved in motility
Flagella
171
types of Flagella
Peritrichous
Polar flagellum
172
how does flagella move
Spin like propellers to
173
three parts of flagella
* Filament - moves
* Hook
* Basal body
174
what is flagella is powered by in bacteria
proton pump
175
what is flagella is powered by in ATP
Archaea
176
Bacteria can sense what
chemicals
177
bacteria response to O2
Aerotaxis
178
bacteria response to earth's magnetic field
Magnetotaxis
179
bacteria response to temperature
Thermotaxis
180
bacteria response to light
Phototaxis
181
are shorter
and thinner than flagella and
the function is differen
Pili (sing. pilus)
182
Common pili
fimbriae
183
allow the bacterial cells to attach to specific surfaces
fimbriae
184
help bacterial cells
move with a twitching or
gliding motility
pili
185
used to join bacteria for DNA transfe
Sex pilus
186
forms the nucleoid
▪Chromosome
187
gel-like region
nucleoid
188
are circular, supercoiled, dsDNA
Plasmids
189
antibiotic resistance can
spread how
sharing Plasmids with other bacteria
190
are involved in protein synthesis
Facilitate joining of amino acids
Ribosomes
191
how are Ribosomes's size expressed
S (Svedberg)
192
Prokaryotic ribosomes are
70S
193
Eukaryotic ribosomes are
80S
194
can transport compounds
Buds off from organelle, fuses with membrane of another
Vesicles
195
Cytoplasmic membrane in eukaryotic cells
hospholipid bilayer embedded with proteins
196
Proteins in outer layer serve as
receptors
197
Bind specific molecule termed
ligand
198
Transport proteins in eukaryotic cells
* Carriers
* Channels
* Aquaporins
199
facilitated diffusion, active transport
Carriers
199
form small gated pores, allow ions to diffuse
Channels
200
water passage
Aquaporins
201
types of Endocytosis
Pinocytosis
Receptor-mediated endocytosis
Phagocytosis
202
most common in animal cells
Liquids and dissolved substances
Pinocytosis
203
Cell internalizes extracellular ligands binding to surface
Receptor-mediated endocytosis
204
used by protozoa, phagocytes to engulf
Phagocytosis
205
is the reverse of endocytosis
Exocytosis
206
* Secreted proteins carry a signal sequence that acts as a tag
* Vesicles transport tagged proteins
Secretion
207
does protein synthesis
ribosomes
208
allow movement
Actin filaments
209
are thickest component.
Make up mitotic spindles to separate chromosomes as cell divide.
Framework for organelle and vesicle movement
Microtubules
210
types of Microtubules
Cilia and flagella
211
provide mechanical support (physical stress)
Intermediate filaments
212
function in motility
Propel via whiplike motion or
thrash back and forth to pull
cell forward
Flagella
213
are shorter, move
synchronously
Can move cell forward or
move material past stationary
cell
Cilia
214
contains DNA
Nucleus
215
Nuclear pores allow
large molecules to pass
216
is region where ribosomal RNAs synthesized
Nucleolus
217
Nucleus surrounded by
two lipid bilayer membranes
218
generate ATP
Mitochondria
219
Mitochondria Bounded by
two lipid bilayers
220
Mitochondrial matrix contains
DNA and 70S ribosomes
221
evolved from bacterial cells
Endosymbiotic theory
222
are site of photosynthesis
Chloroplasts
223
Chloroplasts are found where
plants, algae
224
Harvest light energy to generate ATP
Chloroplasts
225
ancestors of mitochondria
and chloroplasts were bacteria
Endosymbiotic theory
