Lecture 2 Microscopy Cell Morphology Flashcards
(158 cards)
1
Q
What are the two types of cells?
A
Prokaryotic, eukaryotic
2
Q
What is an example of prokaryotic cells?
A
Bacteria
archaea
3
Q
What is an example of eukaryotic cells?
A
Eukarya
4
Q
Which cell is larger?
A
Eukaryotic
5
Q
Which cell is smaller?
A
Prokaryotic
6
Q
What is eukaryotic cells defined by?
A
Presence of a nucleus
7
Q
What is light microscopes magnification?
A
1,000x
8
Q
What is electron microscopes magnification?
A
more than 100,000x
9
Q
Scanning probe microscope can produce images of what?
A
Individual atoms on a surface
10
Q
What are the three concepts of a bright field microscope?
A
Magnification, resolution, contrast
11
Q
What is resolution?
A
Ability to distinguish two objects that are very close together
12
Q
What are the two lens types in a compound microscope?
A
Objective and ocular
13
Q
What are the magnifications of objective lenses?
A
4x, 10x, 40x, 100x
14
Q
What is the magnification of the ocular lens?
A
10x
15
Q
What does the condenser lens do?
A
focuses light on specimen
16
Q
Which lens does not magnify?
A
Condenser lens
17
Q
What is maximum resolving power of the light microscope?
A
0.2 micrometers
18
Q
What is the point of the immersion oil on the 100x objective?
A
Prevents refraction of light, keeps rays from missing openings in objective lens
19
Q
What do stains do in contrast?
A
They increase contrast but kill microbes
20
Q
Electron microscopes use _______ lenses
_______
and _______ screen to replace glass lenses
A
Electromagnetic lenses
electrons
fluorescent
21
Q
Resolving power of electron microscope
A
1,000 or greater
TOTAL power = 100,000x
22
Q
In an electron microscope, lenses and specimen must be in _______
A
vacuum
23
Q
Two types of electron microscopes
A
Transmission Electron Microscope TEM
Scanning Electron Microscope SEM
24
Q
TEM is beam of electrons that pass ________ specimen or scatters
A
Through
25
TEM depends on the ________ of the region
________ is used to view internal details
density
thin-sectioning
26
what microscopy is a newer method that reduces damage to cells and creates 3-D images
Cry-electron microscopy
27
SEM is beam of electrons that scans ________ of specimen
Surface
28
in SEM, electrons are ________ from specimen
Released
29
What is a drop of liquid specimen that is overlaid with a coverslip?
Wet mount
30
What is simple staining?
uses a single dye to stain specimen
31
in a simple stain, what carries the positive charge? what carries the negative charge?
Basic dyes
acidic dyes
32
What are methylene blue and crystal violet?
basic dyes
33
An acidic dye can be done as a ________ ________
wet mount
34
What is differential staining
used to distinguish different groups of bacteria
35
What do gram positive and negative distinguish?
difference in cell wall structure
36
Steps of gram staining
1. crystal violet (primary stain)
2. iodine (mordant)
3. alcohol (decolonizers)
4. Safranin (counterstain)
37
In what step will gram + cells remain purple and gram - cells become colorless?
step 3 (alcohol)
38
What happens to cells in step 3 of gram stian?
gram positive: purple
Gram negative: clear
39
What happens in step 4 of gram stain?
gram positive: purple
gram negative: turns pink
40
What does the success of a gram stain depend on?
The length of time of the decolorizing step (step 3) and the age of culture
41
What is the acid fast stain?
used to detect organisms that do NOT readily take up dyes
42
What does acid fast stain detect?
Mycobacterium species such as causative agents of tuberculosis and Hansen's disease (leprosy)
43
What do the cell walls of mycobacterium contain?
High concentrations of mycolic acids
44
Procedure of the acid fast stain
1. Primary stain is concentrated red dye
2. Acid fast cells retain red dye after being flooded with acid alcohol
3. Methylene blue used as COUNTERSTAIN
45
What is the capsule stain?
Allows observation of gel-like layer that surrounds some microbes
46
What is stained in capsule staining?
The background
47
What is added to the wet mount in capsule stain?
India ink
48
What is endospore stain?
Allows visualization of endospores, resistant dormant cells often formed by Bacillus and Clostridium
49
What do endospores resist?
Gram stain, appears as clear object
50
Endospores stain use what to facilitate the uptake of the primary dye
Heat
51
What is the primary stain of endospore stain
Malachite green
52
What does the counterstain color in endospore stain?
Colors other cells pink that aren't endospores
53
What is the counterstain of endospore stain?
Safranin
54
What is the flagella stain?
uses a substance that makes the dye adhere to thin flagella, making them visible
55
What is peritrichous cell?
Flagella surrounds the cell
56
What is polar cell?
Flagellum on one end
57
immunofluorescence uses what to tag a unique microbe protein?
Fluorescent dye-antibody labels
58
What shape is coccus
Spherical
59
What shape is rod?
Cyclindrical
60
Rod is also called
Bacillus
61
What is short rods called
Coccobacillus
62
Where is great diversity found?
in low nutrient environments
63
list other shapes from least curly to most curly
Vibrio (bent shape)
Spirillum (3 curls)
Spirochete (very curly)
64
Most prokaryotes divide by
Binary fission
65
What shape is staphylococcus
Grape like clusters
66
What shape is sarcina
Cubical packets
67
What shape is streptococcus
Chains
68
What shape is Neisseria gonorrhoeae
Diplococci
69
What layers are in the cell wall of the prokaryotic cell?
cytoplasmic membrane, cell wall, capsule (if present)
70
Where is chromosome located in a prokaryotic cell?
Nucleoid
71
What are the things on the surface of the prokaryotic cell that help with motoin?
pilus
72
What defines the boundary of a prokaryotic cell?
Cytoplasmic membrane
73
What layer is embedded with proteins?
Phospholipid bilayer
74
What tails face in?
Hydrophobic tails
75
What tails face out?
Hydrophilic tails
76
What are the functions of proteins?
Selective gates, sensors of environmental conditions, enzymes
77
What is the fluid mosaic model?
Proteins drift about in lipid bilayer
78
The cytoplasmic membrane is how permeable?
Selectively permeable
79
What passes through the cytoplasmic membrane?
O2, CO2, N2, water, small HYDROPHOBIC molecules
80
Some cells facilitate water passage with ________
Aquaporins
81
How do other molecules that can't permeate the membrane move?
Transport systems
82
What does not pass through the membrane?
Sugars, ions, amino acids, ATP, macromolecules
83
What is simple diffusion?
Movement from high to low concentrations until equilibrium is each
84
What does the speed of diffusion depend on?
concentration
85
The greater the difference in concentration on either side of a membrane, what happens to the rate of the diffusion?
It's higher, increases
86
What is osmosis?
the diffusion of water across a selectively permeable membrane due to UNEQUAL solute concentrations
87
Water diffuses from what areas to what areas?
high water (low solute) concentration to low water (high solute) concentration
88
Water flows from what solution to what solution?
hypotonic to hypertonic
89
There is no net water flow between what soluteions?
isotonic
90
Environment of prokaryotes are typically ________
Dilute/hypotonic
91
Water flows into the cell where the cytoplasm is a ________ solution
Concentrated/hypertonic
92
What prevents the cell from bursting during osmosis?
Cell wall
93
The electron transport chain is embedded in what?
Cytoplasmic membrane
94
The ETC uses energy from ________ to move ________ out of cell
Electrons, protons
95
ETC creates ________ gradient across membrane
Electromechanical
96
Energy in ETC is called
Proton motive force
97
Proton motive force is harvested to drive ________ and some forms of transport/motilify
ATP synthesis
98
Most molecules must pass through proteins functioning as ________
Selective gates
99
Transport systems have
Permeases or carriers
100
What system is highly specific?
Transport system
101
What is the cell wall like in a prokaryotic cell?
strong, somewhat rigid, prevents cell from bursting
102
Cell wall distinguishes what two types of bacteria?
Gram positive, gram negative
103
What is ONLY found in bacteria?
Peptidoglycan
104
What is peptidoglycan shaped like?
alternating series of subunits form glycan chains
105
What are the subunits in glycan chains
N-acetylmuramic acid (NAM)
N-acyetylglucosamine (NAG)
106
What are the chains that link glycan chains?
Tetrapeptide chains
107
What are tetrapeptide chains?
peptide interbridge in gram POSITIVE cells
108
Tetrapeptide only in gram....
Positive
109
The gram positive cell has a thick ________ layer
Peptidoglycan
110
What extends above peptidoglycan layer?
teichoic acids
111
What material is BELOW the peptidoglycan layer?
Gel-like
112
What is the gram negative cell wall have?
Thin peptidoglycan layer
113
Outside the peptidoglycan layer of the gram negative cell is a
unique outer membrane
114
What is the unique outer layer membrane of a gram negative cell made of
Lipopolysaccharide (LPS)
115
What is the function of LPS
Signals immune system of invasion by gram neg cell
- small levels elicit response to eliminate invader
116
What is LPS also called?
Endotoxin
117
What happens when large amounts of endotoxin are accumulating in the blood stream?
Can be deadly
118
What does LPS include?
Lipid A and O antigen
119
Lipid A
Recognized by immune system
120
O antigen
Can be used to identify species or strains
121
Outer membrane of gram neg cell blocks passage of many molecules like
Antibicrobial medications
122
Small molecules and ions can cross the outer membrane via
Porins
123
What is between cytoplasmic membrane and outer membrane?
Periplasmic space
124
What periplasmic space filled with?
gel-like periplasm
125
What happens in the periplasmic space?
Exported proteins accumulate unless specifically moved across outer membrane
126
What part of cell does crystal violet stain?
inside of cell
127
Gram ? cell wall prevents crystal violet-iodine complex from being washed out
positive
128
What dehydrates the thick layer of peptidoglycan
Decolorizing agent
129
What does the decolorizing agent do to the gram neg cell wall?
Damages outer membrane of the cell wall, because thin layer of peptidoglycan can't retain dye complex
130
What bacteria lacks a cell wall?
Mycoplasma
131
What is different about mycoplasma?
It is unaffected by penicillin and lysozyme
cytoplasmic membrane contains sterols that increase strength
132
What is the cell walls of archaea like?
- No peptidoglycan, pseudopeptidoglycan instead
- S-layers that self assemble; built from sheets of flat protein or glycoprotein subunits
133
What is the description of the capsule?
distinct, gelatinous
134
What is the description of slime layer?
Diffuse, irregular
135
Most composed of glycolyx
sugar shell but some are polypeptides
136
Once attached to a surface, cells can grow as _______
biofilm
137
What is a biofilm?
Polymer encased community like dental plaque
138
Some capsules allow bacteria to evade ______-
Host immune system
139
What involves motility?
Flagella
140
What is an important disease related to flagella?
helicobacter pylori
141
What are the three parts of the bacterial flagellum
Basal body
Hook
Filament
142
What is different about archael flagella?
Chemically distinct, use energy from ATP instead of proton motive force
143
What is chemotaxis?
Bacteria sense a chemical and move toward it if its a toxin
144
Movement is a series of what two movements due to coordinated rotation of flagella?
Runs: straight lights
Tumbles: changes in direction
145
Which is longer, pili or flagella?
Flagella
146
Pili that allow surface attachment are called
Fimbriae
147
What movements involve pili?
Twitching motility, gliding motility
148
What do sex pilus do?
joins bacteria for DNA transfer
149
What is endospores?
unique type of DORMANT cell
150
What is endospores produced by
Bacillus, Clostridium
151
What is endospores resistant?
Heat, desiccation, chemicals, UV light, boiling water
152
Endospores can _______ to become _______ cells that can multiply
Germinate, vegetative cells
153
_______ is triggered by limited or nitrogen in endospores
Sporulation
154
What do endospore layers do?
Prevent damage
155
What protects the core of an endospore in dehydrates state and protects from heat?
Cortex
156
what plays an important protective role in endospores sporulation?
Calcium dipicolinate
157
_______ is triggered by heat, chemical exposure
Germination
158
Is germination and sporulation a means of reproduction?
No
