Exam 1 Flashcards
(281 cards)
1
Q
are all microbes germs
A
no–> most are harmless
2
Q
True/false: All microorganisms cannot be seen with the naked eye
A
false
3
Q
what is a microbe
A
- small organisms
- some are microscopic, others can be seen with the eye
4
Q
where did life come from
A
- life began early in our planet’s history with microscopic organisms
- microbial life shaped our atmosphere, our geology, and the energy cycles of all ecosystems
- early microbes eventually evolved into multicellular plants and animals
5
Q
organism
A
the unit element of a continuous lineage with an individual evolutionary history
6
Q
“forms of life”
A
viruses and prions
7
Q
rules for being a living organism
A
- Metabolism (the cell is an open system)
- Reproduction (chemicals from the environment are turned into new cells under the direction of preexisting cells)
3.Differentiation - Communication
- Movement (some organisms are capable of self-propulsion)
- Evolution (cells evolve to display new biological properties. Phylogenetic trees show the evolutionary relationships between cells)
8
Q
early notions of disease, contagion, and containment
A
- notion that disease could be transmitted by invisible things
- Bad air (miasmatic odors– sewage and clean aqueducts built in Roman times)–> protected from epidemics of waterborne illness
- some doctors, philosophers, and scientists also attempted to find what the invisible forces were
9
Q
pasteurization
A
raw milk sterilized to get rid of bacteria
10
Q
germ theory of disease
A
microorganism is responsible for a disease if the microorganism can be isolated from diseased person AND if healthy person comes into contact with microorganism they get sick
11
Q
taxonomy
A
classification, description, identification, and naming of living organisms
12
Q
classification
A
practice of organizing organisms into different groups based on their shared characteristics
13
Q
phylogeny
A
classifying groups of organisms based on their evolutionary relationship
- usually shown by phylogenetic tree
14
Q
phylogenetic tree
A
diagram where groups of organisms are arranged by how closely related they are thought to be
15
Q
How is a microorganism named
A
- binomial nomenclature
- italics
- genus is capitalized
- species name is not
16
Q
prokaryotes
A
- lack a nuclear membrane
- include bacteria and archaea
- no membrane bound organelles
- genetic material floating around in cell
17
Q
eukaryotes
A
- possess a nuclear membrane
- membrane bound organelles
- include fungi, protozoa, and algae
18
Q
bacteria
A
- eubacteria, gram-negative, gram-positive, acid fast, cyanobacteria
- peptidoglycan cell walls
- prokaryotes, unicellular, reproduce by binary fission
- chemoheterotrophs, photoheterotrophs, chemoautotrophs, photoautotrophs
- some bacteria are able to produce endospores
- tetanus, botulism, gonorrhea, chlamydia, tuberculosis
19
Q
photo
A
energy source= light
20
Q
chemo
A
energy source= chemicals
21
Q
archaea
A
- prokaryotic
- if cell wall is present, lack peptidoglycan
- live in extreme environments (methanogens, extreme halophiles, extreme thermophiles)
22
Q
methanogens
A
methane is carbon source
23
Q
extreme halophiles
A
high salt concentrations
24
Q
extreme thermophiles
A
extreme temperatures
25
Algae
- photosynthetic aquatic eukaryotes, photoautotrophs, with cellulose cell walls
- both unicellular and multicellular types
- both sexual and asexual reproductive forms
26
photosynthetic
energy source is sunlight
27
photoautotroph
sun and CO2
28
fungi
- eukaryotes, chemoheterotrophs, produce spores
- yeasts (unicellular fungi), molds (filamentous fungi)
- live in dry conditions, are plant decomposers, chitin cell wall
- molds and mushrooms are multicellular consisting of masses of mycelia, which are composed of filaments called hyphae
29
chemoheterotrophs
energy from chemicals, organic compounds as carbon source
30
helminths
- parasitic
- eukaryote, chemoheterotrophs, flatworms and roundworms
- diseases caused by helminths involve microscopic eggs and larvae
31
protozoa
- eukaryotes
- mainly chemoautotrophs, unicellular, flagellates, ciliates
~30 human pathogens, some are capable of forming cysts
32
microbes in our lives
- majority of microorganisms help maintain the balance of living organisms and chemicals in our environment
- microbes make up most of the Earth's biosphere
- responsible for cycling the many minerals essential for all life (break down waste and incorporate nitrogen on plants)
- used to synthesize chemicals (vitamins, organic acids, vinegar, pickles, cheese, bread, cellulose...etc)
33
microbiota
- bacteria present in the human body
- prevent growth of pathogens
- produce growth factors
34
resistance
- ability of the body to ward off disease
- resistance factors include skin, stomach acid, and antimicrobial chemicals
35
resolution
the smallest distance by which two objects can be separated and still be distinguished
36
microscope
used to magnify or increase the apparent size of an image in order to increase resolution
37
bacterial shapes
- coccus (spherical)
- bacillus (rod-shaped)
- spirillum (wavy bacillus)
- spirochete (spiral)
- star
- square
38
strepto
end to end
39
wavelength
- the distance between troughs or crests
- distance between one peak and the next
40
frequency of the wave
- rate of oscillation
- number of wavelengths in a specific time period
41
electromagnetic spectrum
- shorter wavelength toward violet
- inc energy level and resolving power= dec wavelength
42
conditions needed to resolve an object from its surroundings
- contrast between the object and its surroundings
- wavelength smaller than the object
- a detector with sufficient resolution for the given wavelength
43
absorption
the material captures the energy of a light wave
44
reflection
wave bounces off a material
45
refraction
light bends when it enters a substance that changes its speed
46
scattering
a small fraction of the incident light is scattered in all directions
47
focal point
- where parallel light rays entering the lens emerge at angles so as to intersect each other
48
1 m
1000 mm
49
1000 micrometer
1 mm
50
1000 ng
1000 micrometers
51
low frequency
longer wavelength (inc freq= inc energy= shorter wavelength)
52
refractive index
the extent to which a material slows transmission speed relative to empty space
- large difference between refractive indices of 2 materials= large amt of refraction
53
Antonie van Leeuwenhoek
the first person to create a microscope powerful enough to view microbes
54
Robert Hooke
first to observe cells
55
compound light microscopy
- brightfield microscopy
- darkfield microscopy
- phase contract microscopy
- fluorescence microscopy
56
brightfield microscopy
2 or more lenses that produce dark image on bright background
57
phase contrast microscopy
- uses refraction/interference caused by structures in specimen to create high-contrast, high-resolution images altering wavelengths of light rays passing through specimen
- usually observe live specimen
58
electron microscopy
- scanning electron microscopy (SEM)
- transmission electron microscopy (TEM)
59
longer wavelength
= lower resolution
= higher refraction
60
wavelength of brightfield microscope
increase in resolution is limited by the wavelength of light
61
light and contrast of brightfield microscope
optimal amount of light yields highest contrast between dark specimen and light background
- high contrast needed to achieve maximum resolution
62
lens quality of brightfield microscope
- minimize shape defect
- construct a series of lenses that multiply eah other's magnifications, and correct for aberrations
63
compound light microscope
contains multiple lenses to correct or compensate for aberration
- light source is placed at the bottom, shining upward through a series of lenses
64
how is total magnification calculated
ocular magnification x objective magnification
65
magnification
ability of a lense to enlarge the image of an object when compared to the real object
66
immersion oil
- used to keep light from bending because light may bend in air so much that it misses the small high-magnification lens
67
contrast
visible differences between the parts of a specimen
68
darkfield microscopy
the only light that reaches objective lens is light thats been refracted/reflected by structures in specimen
69
fluorescence microscope
use fluorochromes capable of absorbing energy from a light source and then emitting this energy as visible light
- energy absorption causes electrons to jump to higher energy states, when fall back to ground state, emit photons
- uses fluorescent stains or tags to produce image
- normally has UV, laser, or LED light sources
- normally named for microscopes you can aquire 1D images
70
confocal microscope
uses a laser to scan multiple 2-planes successively
- produces 2D images at various depths that can make 3D image by computer
- uses fluorescence stains or tags to produce an image
- uses lasers as light sources
- can scan multiple planes successively
- produces 2D high-resolution images at various depths
71
electron microscopy
uses short wavelength electron beams rather than light to increase magnification and resolution
- beams of electrons generate images at resolution levels up to a 1000-fold greater than that possible for light microscopy
- can be used to observe subcellular structures/organelles and viruses
72
Transmission Electron Microscopy
- electron beams penetrate thin section of tissue with very high resolution
- electron beam from above the specimen focused on magnetic ions and projected through the specimen onto detectors that captures image
73
Scanning electron microscopy
- electron beams scan the specimen and are reflected by the stain molecules to reveal the contours of its 3D surface
- form images of surface of specimens, usually from electrons that are knocked off specimens by a beam of electrons
74
wet mount
drop of liquid placed on slide
- often stains are added to enhance contrast
75
smear
a bacterial smear is a dried preparation of bacterial cells on a glass slide
76
heat fixation
- fixing= attaching cells to a slide
- smear is fixed on the slide by heat otherwise smear will be washed away during the staining procedure
- heat fixation coagulate bacterial proteins so bacteria stick to the slide surface
77
Once a sample is heat fixed, the bacterial cells on that sample are...
dead
78
staining
- colors certain features of a specimen before examining it under a light microscope
- coloring the microbes with a dye that creates a contrast between the bacteria and the background, emphasizes certain microbial structures
- enables the study of the microbial properties and to group the microbes in specific groups for diagnostics
79
positive stain
dye that will be absorbed by the cells or organisms being observes
- adding color to objects of interest to make them stand out against background
80
acidic dye
negative ion is the chromophore
81
basic dye
- positive charged ion
- cells usually have negative charged cell walls==> this dye sticks to cell walls
82
negative stain
absorbed by the background but not by cells/organisms in the specimen--> produces outline/silhouette of organisms against colorful background
83
simple stains
- use a single dye
- do not distinguish organisms or structures by differential staining reactions
- will make all organisms appear to be the same color
84
differential stains
- use two or more dyes that react differently with various kinds or parts of bacteria, allowing them to be distinguished
- distinguished organisms based on their interactions with multiple stains
85
gram staining
- distinguishes two classes of bacteria
- gram positive cells appear purple
- gram negative cells appear pink
86
gram negative cells
- tend to be more resistant to certain antibiotics than gram positive bacteria
- single layer of peptidoglycan
- outer membrane containing LPS/endotoxin
87
gram positive cells
- multiple layers of peptidoglycan
- no outer membrane, no LPS/endotoxin
88
Ziehl-Nielson Stain
- acid fast stain
- carbolfuschin (red) retained after HCl and ethanol wash step
- color of acid fast: red
- color of non acid fast: red--> colorless--> blue
89
endospore staining
- primary stain= malachite green (stains the spores)
- counter stain (safranin (stains other parts of cell)
90
spontaneous generation
idea that life can arise from nonliving matter
91
spontaneous generation myths
- snakes from horse hairs in stagnant water
- mice from grain and cheese wrapped in sweater
- fleas from hair
- racoons from hollow tree trunks
... etc
92
Redi
- tried to disprove spontaneous generation
- showed that maggots could only form when flies were allowed to lay eggs in the meat and maggots were offspring of flies, not due to spontaneous generation
- BUT scientists did not believe in his work
93
John Needham
- nutrient broth heated, then placed in sealed flask
- resulted in microbial growth
- he likely did not boil the broth for long enough to kill preexisting microbes
94
Lazzaro Spallanzani
- nutrient broth boiled, then sealed
- no microbial growth
95
biogenesis
- living organisms arise from preexisting life
96
germ theory of disease
0 microorganisms can invade macroorganisms and cause disease
97
cell theory
cells arise from other cells
98
endosymbiotic theory
mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship within eukaryotic host
99
Louis Pasteur
- debunked spontaneous generation
- neck of flask twisted so air can get out BUT air/dust can't get in
- when neck broke off, microorganisms could get in and grow
- tilting= nutrient media in neck--> air from environment can get in and microorganisms can grow
100
Robert Koch
proposed series of postulated based on the idea that the cause of a specific disease is a specific microbe
101
Koch's Postulates
- one infectious agent causes one disease
1. the specific causative agent must be found in every case
2. the infectious agent must be isolated in pure culture
3. Inoculation of the pure infectious agent into a susceptible animal must result in the same disease
4. the infectious agent must be recovered from the inoculated animal
102
Can Koch's Postulates be applied to all infectious agents
NO
- can't culture viruses/prions
- some diseases are genetic
- not all bacteria can be cultured in lab
- asymptomatic carriers
103
immunization
- smallpox inoculation was introduced from Turkey by Lady Mary Wortley Montagu
104
aseptic technique
- Ignaz Semmelweis and Joseph Lister
-Semmelweis: found that adequate handwashing limited disease transmission
- Lister: used carbolic acid to sterilize dressings and developed sprays in the surgical room
105
aseptic
sterile
106
monoseptic
equipment contaminated with one microorganism
107
septic
variety of microorganisms
108
Alexander Flemming
- mold contaminant caused a "zone of clearing"
- Penicillin produced
109
antibiotic resistance
- lost effectiveness against certain strains of major pathogens
- caused by widespread and indiscriminate use of antibiotics
110
endosymbiotic theory
theory that mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship within a eukaryotic host
111
evidence for endosymbiotic theory
- they are the same size as bacteria
- double membrane structure identical to gram negative bacteria
- have their own DNA
- DNA arranged like prokaryote (circular)
- have 70S ribosome
- divide independently of the host eukaryotic cell
112
every cell has 4 fundamental properties
1. a cell membrane/plasma membrane/cytoplasmic membrane
2. A cytoplasm ( a gel-like substance composed of water and molecules/materials required for cell growth
3. A chromosome (containing a genetic material
4. Ribosome (where proteins are translated/produced
113
cytoplasm
gel-like network of proteins and macromolecules, required for cellular function
- surrounded by a cytoplasmic/plasma/cell membrane
114
cell membrane
- composed of phospholipid bilayer, small organic molecules and hydrophobic proteins
- prevents cytoplasmic proteins/content from leaking out and maintains the concentration gradients or ions and nutrients
- contains glycans, glycolipids, and glycoproteins
115
cell envelope
structures that enclose the cytoplasm and internal structures of the cell
116
glycans
oligosaccharide chains that are attached to either proteins or lipids
117
glycolipids
lipids with a carbohydrate attached by a glycosidic bond
- maintain cell stability and facilitate cellular recognition
118
grlycoproteins
protein containing glycans attached to amino acid side chains
- some provide structural support
119
cell membrane of eukaryotic cell
- transmembrane proteins (spans through the phospholipid bilayer)
- peripheral proteins: anchored on wither side of the phospholipid bilayer
- function of membrane proteins includes: transport/exchange of substance between the cell and the environment, storage/transfer of energy, reception of external cues and transduction of signal for cellular response, induction of virulence factors and structural support by anchoring multiple layers of the cell envelope
120
simple diffusion
- passive transport
- movement of molecules across the membrane, down a concentration gradient
- no energy required
121
facilitated diffusion
- used for charged/large molecules that need carriers/channels in the membrane
- passive transport
122
active transport
- uses energy (spends energy)
- move molecules against concentration gradient
- "pumps"
- energy carrier molecule- ATP
- energy potential across the membrane- Proton motive force
- group translocation- substance is chemically altered to create a down gradient
123
symport
- active transport
- molecules that are co-transported move in the same direction
124
antiport
- active transport
- molecules that are exchanged move in opposite direction
- exchanged for each other
- don't move at same time
125
ABC system
- active transport
- ATP binding cassette
- made up of 3 proteins that form a membrane channel and 2 cytoplasmic proteins that contains a conserved motif that is capable of binding/hydrolyzing ATP
126
group translocation
- active transport
- a substance is chemically altered during its transport across a membrane so that once inside, the cytoplasmic membrane becomes impermeable to that substance and it remains within the cell
- energy for this process is provided by POP, a high energy phosphate compound
- as molecule moves into a cell against concentration gradient, it is chemically modified so it doesn't require transport against unfavorable concentration gradient
127
capsule
contributes to virulence of gram positive bacteria
- attachment and prevents phagocytosis
128
peptidoglycan
unique to bacteria
- antibiotics are sometimes designed to interfere with peptidoglycan synthesis, weakening cell wall and making bacterial cells more susceptible to the effects of osmotic pressure
129
Do both gram positive and gram negative bacteria have a periplasmic space
yes
130
important functions of cell wall
1. maintains the characteristic shape of the cell. If it is digested by enzymes then the cell becomes round
2. Prevents the cell from bursting when fluids flow into the cell by osmosis. Although it surrounds the bacteria, it is porous and does not play a major role in preventing the passage of the fluids
131
S-layer
cell envelope structure
- composed of a mixture of structural proteins and glycoproteins
- found outside cell wall
132
capsule
- made up of glycosyl chains
- inhibits phagocytosis
133
protoplast
- wall-less cell
- susceptible to osmotic lysis
134
spheroplast
- wall-less gram-positive cell
- susceptible to osmotic lysis
135
L forms
wall-less cells that swell into irregular shapes
136
Peptidoglycan (murein)
- most important component of cell wall
- consists of parallel polymers of disaccharides celled glycan chains
- contain D-alanine and D-glutamate
137
glycan chains
- made up of two alternating sugar units
- N-acetylglucosamine (NAG)
- N-acetylmuramic acid (NAM)
138
alternating sugar units
joined by beta (1,4) glycosidic bonds
139
parallel glycan strands
linked by short peptide cross bridges containing three to five amino acid residues
140
sequence of cross bridge forming peptide
L-alanine, D-glutamic acid, m-diaminopimelic acid, D-alanine
141
gram positive cell wall
have a peptide interbridge
142
gram negative cell wall
lack interbridge
143
lysozyme
digests disaccharide in peptidoglycan
144
penicillin
inhibits peptide bridges in peptidoglycan
- binds to transpeptidase (the enzymes that hydrolyze the peptidoglycan cross-links continue to function which weakens the cell wall of the bacterium)
- the antibiotic causes cytolysis/death due to osmotic pressure
145
Vancomycin
prevents cross-bridge formation by binding the terminal D-Ala-D-Ala dipeptide, preventing release of the terminal D-alanine
- cells resistant to vancomycin contain an altered enzyme that adds lactic acid in place of the terminal D-alanine. The altered enzyme is no longer blocked by vancomycin
146
Beta-lactamase
cleaves penicillin, preventing it from inhibiting transpeptidase
147
techoic acid
additional component found in cell walls of gram-positive bacteria
- consists of glycerol, phosphates, and ribitol
- occurs in polymers of up to 30 units
- phosphodiester links are deprotonated, with a negative charge
148
lipoteichoic acid
- gram positive bacteria
- techoic acid but it is anchored to the lipid bilayer by a glyceride
- extends beyond the rest of the cell wall even beyond the capsule
149
functions of lipoteichoic acid
1. attachment site for bacteriophages
2. help pathogens attach to host
3. passageway for movement of ions in/out of cell
4. they are bacterial signatures-- recognized by the immune system
150
surface proteins in gram positive bacteria
| function
- carry out different activities based on strain and species
1. functioning as enzymes
2. serving as adhesions to enable the bacterium to adhere intimately to host cells and other surfaces in order to colonize and resist
3. occasionally functioning as invasins and enable some bacteria to penetrate host cells
4. aiding certain bacteria in resisting phagocytic destruction
151
gram negative bacteria outer membrane
- bilayer membrane
- has surface antigens and receptors
- forms outermost layer of the cell wall
- attached to the peptidoglycan by a continuous layer of lipoprotein molecules which are embedded in the outer membrane
- has little/no control on the movement of substances into and out of the cell
152
porins
- gram negative
- form channels through the outer membrane and allow small molecules to enter the cell
153
periplasm gram negative bacteria
easily observed by electron microscopy
- very active area of cell metabolism
154
Lipopolysaccharide
- gram negative
- called endotoxin
- released when the cell walls of a bacteria is broken down (when a bacteria dies)
- O-specific polysaccharide used in diagnostic methods
- integral part of cell
- consists of repeating side chains of polysaccharides and lipid A
- lipid A is responsible for toxic properties
- fever, dilates blood vessels, blood pressure drops
155
acid fast bacteria
- considered gram positive
- their envelopes are exceptionally thick and complex
- includes extra layers not found in other gram positive cells
- acid fast staind must be used to penetrate the mycolic acid layer for microscopy
156
mycoplasma
- lack cell walls
- sterols in plasma membrane
157
archaea cell walls
- wall less or walls made of pseudomurein (lack NAM and D-amino acids)
158
what happens if a bacteria lacks a cell wall
bacteria would lose its shape and wouldn't be able to withstand osmotic pressure
159
isotonic solution
- same solute concentration as another solution
- no net movement of water
160
hypertonic solution
- solution that has a higher solute concentration than another solution
- water particles will move out of the cell causing crenation
161
hypotonic solution
solution that has lower solute concentration than another solution
- water particles will move into the cell, causing the cell to expand and eventually lyse
162
osmosis
water diffuses across membrane from side with lower concentration to higher concentration until concentrations become equal
163
tonicity
the degree to which a particular cell is able to withstand changes in osmotic pressure
- cells that have cell wall are better able to withstand subtle changes in osmotic pressure and maintain their shape
164
nuceloid
prokaryotic DNA and DNA-associated proteins are concentrated within nucleoid region
165
inclusions
reserves that some prokaryotic cells use to store excess nutrients within cytoplasm
- storing nutrients in a polymerized form is advantageous because it reduces the buildup of osmotic pressure that occurs as a cell accumulates solutes
166
metachromatic granules
phosphate reserves
167
polysaccharide granules
energy reserves
168
lipid inclusions
energy reserves
169
sulfur granules
elemental sulfur for metabolism
170
carboxysomes
ribulose 1,5-diphosphate carboxylase for CO2 fixation
171
gas vaculoles
protein-covered cylinders for buoyancy
172
magnetosomes
iron oxide (destroys H2O2)
- allow for attachment
173
vegetative cells
how bacterial cells are generally observed
174
endospores
structures that essentially protect the bacterial genome in a dormant state when environmental conditions are unfavorable
- allows bacteria to survive long periods without food, water, exposure to chemicals and harsh environmental conditions
175
sporulation
- the process by which vegetative cells transform into endospores
- DNA replicates-> membranes form around DNA-> forespore forms additional membranes-> protective cortex forms around spore-> protein coat forms around cortex-> spore is released
176
flagella
- structures used by cells to move in aqueous environments--> bacterial flagella act like propellers
- stiff spiral filaments composed of flagellin subunits that extend outward from cell and spin in solution
177
basal body
motor for the flagellum and is embedded in the plasma membrane
178
hook
connects the basal body to the filament
179
monotrichous
- singular flagellum
- typically located at one end of the cell
180
amphitrichous
- have a flagella/tufts of flagella at each end
181
lophotrichous
flagella have tuft at one end of the cell
182
peritrichous
flagella that cover the entire surface of a bacterial cell
183
CCW
moves cell toward attractant
184
CW
stops forward motion, so cell tumbles and changes direction
185
chemotaxis
bacteria moving toward nutrient signal
186
axial filaments
- also called endoflagella
- in spirochetes
- anchored at one end of a cell
- rotation causes cell to move
187
fimbriae
short bristle-like proteins projecting from cell surface by the hundreds
- enable cell to attach to surfaces and other cells
188
pili
longer, less numerous protein appendages that aid in attachment to surfaces
189
F pili
sex pilus
- important in transfer of DNA between bacterial cells
190
glycocalyx
- carbs extending from animal plasma membrane
- bonded to proteins and lipids in membrane
191
plasma membrane (eukaryotic cells)
- phospholipid bilayer
- peripheral proteins
- integral proteins
- transmembrane proteins
- sterols
- glycocalyx carbs
192
prokaryotic ribosome
30S+50S=70S
193
eukaryotic ribosome
80S
194
chloroplast and mitochondria ribosome
70S
195
S
- Svedburg
- used as a measure of sedimentation rate in an ultracentrifuge
196
nucleus
- controls cell activity
- essential in reproduction/heredity
- surrounded by nucelar membrane
- contains chromosomes
197
ER
- transport network
- rough ER: makes proteins destined from plasma membrane
- smooth ER: involved in biosynthesis of lipids, carbs, metabolism, and detoxification
198
Golgi
- membrane formation and secretion
- modify lipids/proteins from ER
199
lysosome
- digestive enzymes
- break down food, damaged organisms, microorganisms
200
vacuole
- brings food into cells and provides support
201
mitochondrion
cellular respiration
202
chloroplast
photosynthesis
203
peroxisome
oxidation of fatty acids; destroys H2O2
204
Centrosome
consitis of protein fibers and centrioles
205
cytockeleton
internal network that supports transport of intracellular components and helps maintain cell shape
206
eukaryotic flagella
- more flexible whip composed of 9 parallel pairs of microtubules surrounding a central pair
- moves by dynein motor
207
common characteristics of eukaryotic and prokaryotic cells
- both surrounded by cell membrane
- both may or may not have a cell wall
208
how are prokaryotes and eukaryotes different
- eukaryotic cells have extensive organization and partition as opposed to prokaryotes
- prokaryotes are unicellular
- prokaryotes include 2 groups: Archaea and eubacteria
- eukaryotes may be unicellular or multicellular and include all animals, plants, algae, fungi, and protists
209
metabolism
all the chemical reactions that take place within a cell
210
exergonic
spontaneous and releases energy
211
endergonic
requires energy
212
catabolism
breaking down complex organic molecules
- a species can catabolize only those substances for which its DNA encodes the right enzymes
213
anabolism
small molecules are assembles into larger ones
- uses energy
214
maintaining cell's energy balance
need catabolism and anabolism
215
oxidation reactions
remove electrons from donor molecules leaving them oxidized
216
reduction reaction
add electrons to acceptor molecules leaving them reduced
217
redox reactions
- oxidation and reduction occur in tandem
- oxidation: loss of electrons
- reduction: gain of electrons -
218
most common energy carriers
- NADH (NAD+ is reduced to NADH)--> catabolism
- FADH2--> catabolism
- ATP--> "energy currency" of cell
- NAPD+/NADPH--> anabolic reactions
219
coenzyme
organic helper molecules that are requires for enzyme action
220
cofactor
inorganic
221
phototrophy
light-energy absorption makes high-energy molecule that donates electrons to acceptor
222
chemotrophy
high-energy food molecule donates electron to acceptor
223
organotrophy, aerobic
- organic molecules donates electrons to O2
224
organotrophy, anaerobic
organic molecule donates electrons to itself or other molecule, not O2
225
lithotrophy, aerobic
- inorganic molecule donates electrons to O2
226
lithotrophy, anaerobic
- inorganic molecule donates electrons to other molecules, not O2
227
enzymes
lower activation energy of chemical reactions
228
glycolysis (EMP Pathway)
- energy investment phase= uses energy from 2 ATP molecules to split glucose into 2 G3P molecules
- Energy payoff phase= oxidizes G3P to pyruvate, producing 4 ATP and reducing 2 NAD+ to 2 NADPH
- net gain: 2 ATP, 2 NADH, 2 pyruvate,
229
other glycolytic pathways
- Entner-Doudoroff (ED Pathway)
- Pentose Phosphate Pathway
230
transition reaction
electrons tranferred to NAD+ to form NADH, pyruvate oxidized to acetyl group which is attached to a CoA carrier
231
Krebs cycle
- transfers remaining electrons from acetyl group produced during transition reaction to electron carrier molecules
- Per turn of the cycle: 2 CO2, 3 NADH, 1 FADH2, 1 ATP
232
cellular respiration
- the process of catabolism from substrate breakdown to reduction of a terminal electron acceptor
- completes catabolism by donating electrons from NADH to the ETS in a process that stores energy by pumping protons across the membrane to generate a gradient of hydrogen ions
- hydorgen ions return to the cell via ATP synthase, driving formation of ATP= oxidative phosphorylation
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electron transport system under aerobic conditions
final electron acceptor is an oxygen molecule that gets reduced to water
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anaerobic respiration
uses inorganic molecule other than oxygen as final electron acceptor
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overall equation for the respiration of glucose with oxygen
C6H12O6 + 6H2O +6O2 --> 12H2O + 6CO2
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glucose respiration
- can generate a relatively large number of ATP molecules per molecule of glucose, far more than in fermentation
- actual number of ATP molecueles generates varies widely with the availability of a carbon source and oxygen source
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proton motive force
- electrochemical gradient formed by the accumulation of H+ on one side of the membrane compared with the other
- used to make ATP and used to drive energetically unfavorable processes (nutrient transport and flagella rotation)
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lithotrophy
an inorganic reduced molecule such as ferrous iron (Fe2+), ammonium ion(NH4-) or hydrogen gas(H2) donates electrons to the first oxidoreductase of the ETS
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fermentation
- if respiration does not occur, NADH must be re-oxidized to NAD+ for reuse
- max 2 ATP produced per glucose
- uses organic molecule as a final electron acceptor
- does not involve electron transport system and does not produce ATP beyond with is produced in glycolysis
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fermentation vs respiration
- fermentation: occurs when the electrons of NADH are put back onto pyruvate, forming waste products such as lactic acid
- Respiration: occurs when NADH donates electrons to the electron transport system (ETS_ which ultimately transfers them to O2 or to an alternative inorganic molecule
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background of coronavirus
- affect respiratory tract og birds and mammals (common cold, bronchitis, pneumonia, SARS)
- first coronavirus isolated in 1937 (from birds)
- 1960s: isolated from patients with common cold
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COVID-19 infectious agent
- coronaviridae
- enveloped, spherical or pleomorphic, +SSRNA
- viral particles contain characteristic spikes-- club or petal shaped resembling a solar corona
- SARS, SARS-CoV-2, can be lethal
- binds to ACE2 inhibitors
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COVID-19 transmission
- person to person through aerosols
- fomites
- animal to person (zoonotic disease)
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variant of interest
- a SARS-CoV-2 variant with genetic changes that are predicted/known to affect: transmissibility, disease severity, immune escape, diagnostic escape, therapeutic escape
- AND cause significant community transmission in multiple countries with increasing relative prevalence and increasing number of cases over time
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variant of concern
- a SARS-CoV-2 variant meeting definition of a VOI and associated with one or more of the following changes globally: increased transmissibility, detrimental change in epidemiology, increase in virulence, change in clinical disease presentation, decrease in effectiveness of public health/social measures, available diagnostics, vaccines, therapeutics
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variants of COVID-19
alpha, beta, gamma, delta, omicron
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current VOC
- Delta: 15 spike substitution, inc transmissibility, nearly all lineages susceptible to monoclonal antibody treatments, reduction in neutralization by post-vaccine sera
- omicron: 34 spike protein substitutions, potential for all of the above
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COVID-19
| incubation, contagious
- incubation is typically 10-14 days
contagious 3-5 days before symptoms
- asymptomatic carriers are common
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COVID 19 symptoms
- may appear 2-14 days after exposure
1. fever/chills
2. cough
3. shortness of breath or difficulty breathing
4. fatigue
5. muscle or body aches
6. headache
7. new loss of taste/smell
8. sore throat
9. congestion or runny nose
10. nausea or vomiting
11. diarrhea
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incubation period of COVID19
- original strain/early variants: 5 days
- delta: 4 days
- omicron: 3 days
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viral load
amount of virus that build up in someone's body
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viral load of COVID19
- Alpha and delta: peak viral load at 3 days after infection; virus cleared 9 days after infection
- omicron: same or slightly lower average viral load, infection cleared one day sooner than delta
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COVID 19 complications
severe pneumonia
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long covid
- post-exertional malaise
- brain fog
- heart palpitations
- pins and needles
- sleep problems
- lightheadedness
- rash
- mood changes
- changes in menstrual period
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diagnosis of COVID19
- viral test: used to determine if you have an active COVID19 infection at time of test
- antibody test for presence of IgG and IgM antibodies: developed in response to past infection
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COVID19 treatment
1. Remdesivir
2. Dexamethasone
3. Baricitinib
4. Monoclonal antibodues
- pain and fever medications
- antihistamines
- humidifier
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COVID19 prevention
- vaccine
- mask
- 1 meter distance
- avoid crowds
- wash hands
-cough into elbo
- stay home if sick
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4 types of COVID vaccine
1. whole virus vaccine
2. RNA/mRNA vaccine
3. non-replicating viral vector
4. protein subunit
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vaccines for COVID approved in the US
- Pfizer
- Moderna
- Johnson and Johnson
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infectious agent of plague
gram negative bacterium Yersinia pestis
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transmission of the plague
- the bite of fleas that have previously fed on infected animals like mice, rats, rabbits, squirrels, chipmunks, and prarie dogs
- direct contact with an infected person or animal, or y eating an infected animal
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where does the plague occur
- endemic to rural areas in:
- central and southern Africa
- central Asia and Indian subcontinent
- NE part of south america
- SW US
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incubation period of the plague
1-6 days
264
bubonic plague symptoms
- rapid onset of fever
- painful, swollen, and tender lymph nodes
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pneumonic plague symptoms
- high fever
- overwhelming pneumonia
- cough
- bloody sputum
- chills
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septicemic plague symptoms
- fever
- prostration
- hemorrhagic or thrombotic phenomena
- progressing to acral gangrene
267
diagnosis of the plague
- sample: isolation of bacteria from bubo aspirates, blood cultures, or sputum culture (if pneumonic)
- identification: culture, serologic tests for the Y. pestis F1 antigen
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treatment of the plague
- Antibiotics: gentamicin, doxycycline, ciprofloxacin, levofloxacin
- Parental antibiotics: moxifloxacin, streptomycin, and chloramphenicol
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prevention of the plague
- keep rodent population under control in your home, workplace, and recreation area
- keep the home free from stacks of cluttered fireworrd or piles of rock, brush, or other debris that could attract rodents
- protect pets from fleas using flea control products
- use insect repellent
- vaccine (no liscenced vaccine available)
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managing plague outbreaks
- find and stop the source of infection
- protect health workers
- ensure correct treatment
- isolate patients with pneumonic plague
- surveillance
- obtain specimens
- dinsinfection
- ensure safe burial practices
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Smallpox infectious agent
- variola virus, dsDNA
- member of the genus Orthopoxvirus
- a characteristic feature of their virus is its strict specificity for humans
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transmission of smallpox
person to person
273
smallpox eradication
- only in vials in BSL-4 labs
- only risk for personnel that perform research on smallpox
- can be used as a biological agent
- Africa: closely related monkeypox remains endemic (produces smallpox-like symptoms, not as lethal
274
smallpox incubation period
7-19 daays
275
signs and symptoms of smallpox
1. initial symptoms: high fever, head and body aches, sometimes vomiting, sometimes contagious
2. Early rash: lasts about 4 days, most contagious
3. Pustular rash and scabs: lasts about 10 days, contagious
4. Scabs fall off: lasts about 6 days, contagious
5. No scabs: four weeks after the rash appears, all scabs should have fallen off, once all scabs have fallen off, the person is no longer contagious
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variola major
severe, and most common
- overall fatality rate: 30%
277
Variola minor
- less common
- less severe
- death rate is less than 1%
278
diagnosis of smallpox
- sample: isolation of virus from blood samples or pustule sample
- identification: culture, serologic tests for the virus antibodies
279
treatment of smallpox
- no current official treatment available
- tecovirimat
- cidofovir and brincidofocir have been shown to be effective against the virus that causes smallpox
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smallpox prevention
- vaccination (not widely available anymore)
- if given with 4 days of exposure, the vaccine can prevent/lessen the severity of symptoms
- vaccination 4-7 days after exposure may offer some protection from the disease and may lessen its severity
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smallpox as a bioterrorism threat
- considered one of the most serious bioterrorist threats
- was used as a biological weapon during the French and Indian Wards when British soldiers distributed smallpox-infected blankets to American Indians
- In the 1980s, the Soviet Union developed variola as an aerosol biological weapon and produced tons of virus-laden material annually intended for intercontinental ballistic missiles
