Lectures 1 & 2 Flashcards
(139 cards)
1
Q
what are the two fundamental cell types?
A
prokaryotic and eukaryotic
2
Q
which cell type has a nucleus?
A
eukaryotic
3
Q
what is resolving power?
A
determines how much detail can be seen in the observed specimen
4
Q
what is unique about scanning probe microscopes (what can they do)?
A
can produce images of individual atoms on a surface
5
Q
what are the three principles of light microscopy?
A
magnification, resolution, contrast
6
Q
what does resolution depend on?
A
quality and type of lens, wavelength of light, magnification, specimen preparation
7
Q
what is resolution?
A
the ability to distinguish two objects that are very close together
8
Q
why can you not observe living cells through staining?
A
it kills the cells
9
Q
what determines how easily cells can be seen?
A
contrast
10
Q
what does a condenser lens do?
A
focuses light on specimen
11
Q
how are wavelength and resolving power related?
A
lower wavelength results in higher resolving power
12
Q
what is the maximum resolving power of light microscope?
A
0.2 micrometer
13
Q
what does immersion oil do?
A
prevents refraction of light and keeps rays from missing opening in objective lens
14
Q
how can contrast be increased?
A
stain
15
Q
what is dark field microscopy?
A
cells appear as bright objects against dark background
16
Q
which bacterias is dark field microscopy often used to see?
A
syphillis pathogen, gonarrhea, or Lyme disease pathogen
17
Q
name the features of electron microscopy
A
uses electromagnetic lenses, electrons, and a fluorescent screen to replace glass lenses, visible light, and the eye
18
Q
what is the resolving power of an electron microscope?
A
0.3 nanometer (1000x greater than light microscope)
19
Q
what are the two major types of electron microscopes?
A
transmission and scanning electron microscope
20
Q
why must lenses and specimen be in a vacuum during electron microscopy?
A
air molecules would interfere with electrons
21
Q
describe transmission electron microscope
A
beam of electrons passes through specimen or scatters
22
Q
how is thin-sectioning different than freeze-fracturing?
A
both view internal details; however, thin sectioning is dehydrated then cut, freeze-fracturing is frozen then broken in half like a coconut
23
Q
describe scanning electron microscope
A
beam of electrons scans over surface of specimen
24
Q
which type of electron microscopy is used to observe surface details?
A
SEM
25
what are wet mounts used to observe?
living organisms
26
what are the two differential stains?
gram stain and acid-fast stain
27
what are the types of special stains?
capsule stain, endospore stain, flagella stain
28
what are examples of simple stains?
methylene blue and crystal violet
29
what is different about gram positive and gram negative stains?
chemical structure of the cell walls
30
what are acidic dyes used for?
negative staining (colors background)
31
which genus do acid-fast stains take up?
mycobacterium
32
how can you tell if a patient has tuberculosis?
use an acid-fast stain
33
what are the types of fluorescent dyes and tags?
fluorescent dyes and tags
34
most bacteria is ____ charged
negatively
35
basic dyes carry which type of charge?
positive
36
which dyes are used for negative staining?
acidic dyes
37
what is the state of bacteria and the end of the staining process (gram stain)?
gram positive cells remain purple, gram negative cells appear pink
38
a patient possibly has a UTI. which stain is used to confirm?
gram stain
39
what is the function of a mordant in a gram stain procedure?
it stabilizes the dye in the cell and it reacts with the dye to form a complex that is less likely to be washed from the cell
40
what does iodine do in a gram stain?
stabilizes dye in cell
41
what does the decolorizing agent do in a gram stain?
removes dye-iodine complex from gram negative, but not gram positive bacteria
42
what does safranin do in a gram stain?
give color (pink) to the colorless gram negative bacteria
43
what is the order of staining in a gram stain?
crystal violet (primary)
iodine (mordant)
alcohol (decolorized)
safranin (counterstain)
44
what is the counterstain in an acid-fast stain?
methylene
45
name some examples of diseases caused by mycobacterium (also which staining method is used to uptake them?)
tuberculosis, Hansen's disease (leprosy)
acid-fast stain
46
what are endospores?
resistant dormant cells often formed by bacillus and clostridium
47
what colors are associated with the visualization of endospores in endospore stains?
endospores become green, and the counterstain (safranin) colors other cells pink
48
what do capsule stains allow observation of?
the gel-like layer that surrounds some microbes
capsule stains poorly, so background is stained to make capsule visible
49
what is the purpose of a flagella stain?
it uses a substance that makes the dye adhere to the thinnn flagella, making them visible
50
how do prokaryotes divide?
binary fission
51
result of prokaryotic cells dividing in one plane
diplococcus or chain of cocci (draw and check)
52
result of prokaryotic division in two or more planes perpendicular to one another
packets
53
result of prokaryotic division in several planes at random
clusters
54
example of diplococci
neisseria gonorrhoeae
55
example of chains of prokaryotic division
streptococcus
56
example of cubical packets (division)
sarcina
57
example of grape-like clusters (division)
staphylococcus
58
what is a peritrichous flagella?
flagella surrounds cell
59
what is a polar flagella?
flagellum on one end
60
describe coccus bacteria
spherical
61
describe rod bacteria
cylindrical, also called a bacillus
62
what are short rod bacteria called?
coccobacillus
63
water flows from ________ solution to _______ solution.
hypotonic; hypertonic
64
there is no_________ between isotonic solutions
net water flow
65
what are some functions of proteins in the cytoplasmic membrane?
selective gates
sensors of environmental conditions
enzymes
66
what do aquaporins do?
facilitate water passage
67
Dilute solution are (hypertonic or hypotonic)
hypotonic
68
Compare gram positive and gram negative bacteria: peptidoglycan
GP: thick layer
GN: thin layer
69
Compare gram positive and gram negative bacteria: teichoic acids
GP: present
GN: absent
70
Compare gram positive and gram negative bacteria: outer membrane
GP: absent
GN: present
71
Compare gram positive and gram negative bacteria: Lipopolysacharride (endotoxin)
GP: absent
GN: present
72
Compare gram positive and gram negative bacteria: Porin proteins
GP: absent (no outer membrane)
GN: present
73
Compare gram positive and gram negative bacteria: sensitive to penicillin
GP: more
GN: less
74
Compare gram positive and gram negative bacteria: Sensitive to lysozyme
GP: yes
GN: no
75
what freely passes through the cytoplasmic membrane?
oxygen, carbon dioxide, nitrogen, small hydrophobic molecules, water
76
where is peptidoglycan found?
only in bacteria
77
what are the subunits that form glycan chains?
NAM and NAG
78
what extends above the peptidoglycan layer in the gram positive cell wall?
teichoic acids
79
what is the outer membrane of the gram negative cell wall?
lipopolysacharride (LPS)
80
what is LPS also called?
endotoxin
81
what is the function of lipopolysacharride?
signals immune system of invasion by gram-negative bacteria, and small levels elicit response to eliminate invader
82
where/ what is Lipid A?
gram-negative cell wall, it is recognized by the immune system
83
where/what is O antigen?
in gram-negative cell wall; it can be used to identify species or stains
84
how do small molecules and ions cross the GN cell wall?
porins
85
what is the function of the outer membrane of the GN cell wall?
blocks passage of many molecules
86
what is between the cytoplasmic membrane and outer membrane of the GN cell wall?
periplasmic space
87
what is the periplasmic space filled with?
gel-like periplasm
88
where do exported proteins accumulate in the GN cell wall?
periplasmic space
89
how does the gram-positive cell prevent the crystal violet- iodine complex from being washed out?
the decolorizing agent dehydrates the peptidoglycan (its a thick layers), so this thick, dry layer becomes a barrier
90
why can the GN cell wall not retain the dye complex?
the thin layer of peptidoglycan
91
what is an example of a bacteria that does not have a cell wall?
mycoplasma
92
why is mycoplasma unaffected by penicillin and lysosome?
it does not have a cell wall
93
how do mycoplasma species remain strong without a cell wall?
cytoplasmic membrane contains sterols that increase strengths.
94
what are the s-layers of archaea built from?
sheets of flat protein or glycoprotein subunits
95
what are the capsule and slime layer mostly composed of?
glycocalyx (sugar shell), but some are polypeptides
usually made of polysaccharide
96
what is the capsule and slime layer?
it is a gel-like layer outside the cell wall that protects or allows attachement
97
what do cells grow as once they attach to a capsule or slime layer?
biofilm
98
what is an example of biofilm?
dental plaque
99
which flagella is important in disease?
helicobacter pylori
100
what are the three parts of bacterial flagellum?
basal body
hook
filament
101
which part of flagellum anchors to the cell wall and cytoplasmic membrane?
basal body
102
how do archael flagella move?
use energy from ATP instead of proton motive force
103
what is chemotaxis?
bacteria senses a chemical and moves towards it (nutrient) or away from it (toxin)
104
how do flagella move during chemotaxis?
runs and tumbles
105
what are pili that allow surface attachment?
fimbria
106
what do sex pillus do?
used to join bacteria for a type of DNA transfer
107
what do endospores germinate into?
vegetative cells that can multiply
108
what is sporulation triggered by?
limited carbon or nitrogen
109
what is germination in endospores triggered by?
heat or chemical exposure...NOT a means of reproduction
110
what does calcium dipicolinate do?
plays an important protective role in sporulation of endospores
111
what is the difference between prokaryotic and eukaryotic cells?
prokaryotic do not have a membrane bound nucleus
eukaryotic have a membrane bound nucleus and organelles
112
what are the three domains that all living cells can be classified as?
bacteria, archaea, and eukarya
113
which domain has peptidoglycan in the cell walls?
bacteria (not archaea or eukarya)
114
name the four types of eukaryotes
algae, protozoa, fungi, helminths
115
which type of eukaryotic organism uses sunlight for energy?
algae
116
what are the acellular infectious agents?
viruses, viroids, prions
117
what is the human microbiome project?
DNA sequencing studies to characterize microbial communities that inhabit the human body
118
which acellular infectious agents consist of DNA or RNA?
viruses can consist of either, viroids only consist of RNA
119
which acellular infectious agent consists of protein?
prions
120
what is an emerging infectious disease?
one that has become more common in the last 35 years; examples include ebola, zika, MERS, and the influenza
121
what are examples of chronic diseases once thought to have genetic origins, but are caused by microbial pathogens?
stomach ulcers are caused by helicobacter pylori, and cervical cancer is caused by HPV
122
what do plasmids of prokaryotic cells do?
carries genetic information that may be advantageous to the cell in certain situations
123
do archaea have peptidoglycan?
no
124
which domain do extremophiles belong to?
archaea
125
what are protists?
another term for algae and protozoa
126
what is bioremediation?
use of microorganisms to hasten decay of pollutants
127
how do immunofluorescent stains work?
uses fluorescent dye-antibody labels to tag a unique microbe protein
128
draw a vibrio, spirillum, and spirochete prokaryotic cells?
do it right!
129
what is nitrogen fixation?
microbes are the only organisms that can fix atmospheric N2 into amino nitrogen (NH3)
130
which bacterial genera lack cell walls?
mycoplasma
131
the environment of prokaryotes are typically....
dilute (hypotonic)
132
describe the cytoplasmic membrane
the phospholipid bilayer is embedded with proteins
the hydrophobic tails face in, and the hydrophilic heads face out
the fluid mosaic model describes the proteins that drift about in the lipid bilayer
it is selectively permeable
133
what is the representative genera of gram positive bacteria?
bacillus, staphylococcus, streprococcus
134
what is the representative genera of gram negative bacteria?
escherichia, neisseria, pseudomonas
135
what links the glycan chains in peptidoglycan?
tetra peptide chain
136
what interbridge is unique to gram positive bacteria?
the peptide interbridge
137
what does penicillin do to peptidoglycan?
interferes with peptidoglycan synthesis
138
what does lysozyme do to peptidoglycan?
destroys structural integrity of peptidoglycan
139
what prevents the uptake of dyes in mycobacterium?
mycolic acids
