Microbiology Test 1 Campbell – Flashcards

question
What is microbiology?
answer
Microbiology is the study of organisms which are usually seen by a microscope, not the unaided eye.
question
Prokaryotic vs. Eukaryotic
answer
Prokaryotic cells came into existence before the eukaryote. They do not have membrane bound organelles or a nucleus. Eukaryotic cells have a nucleus and membrane bound organelles
question
Carl Woese
answer
He created Domain, which is used as a classification system. It showed 2 distinct types of groups, Bacteria and Archaea
question
Prokaryotes
answer
Majority have cell wall with peptidoglycan. Reproduce by binary fission. About 0.3-5 nanometers.
question
Significance of Cyanobacteria
answer
produces significant amounts of oxygen; photosynthetic
question
Archaea
answer
Distinguished from bacteria by unique rRNA gene sequences. Lack peptidoglycan in cell walls. Have unique membrane lipids. Many live in extreme environments (hydrothermal vents, dead sea)
question
Protozoans
answer
unicellular, motile, sexual and asexual reproduction
ex: phytoplankton (photosynthetic)
question
Algae
answer
unicellular and multicellular
photosynthetic
question
Fungi
answer
unicellular and multicellular
Ex: yeast
question
Multicellular Parasites
answer
Helminths- parasitic worms
ex: roundworms, flatworms, flukes
question
Are virus' considered organisms
answer
No, they are considered infectious agents
question
Viruses
answer
Obligate intracellular agent
Consists of either DNA or RNA, surrounded by a protein coat
question
Viroid and Virusoids
answer
Consist of only RNA; no protein coat
question
Prions
answer
consists only of protein, no DNA or RNA
ex: Mad cow disease
question
Why did RNA exist before DNA?
answer
RNA was first because it could store information and was catalytic and DNA is NOT catalytic, only a storage molecule
question
The Endosymbiotic Theory
answer
The theory that states that mitochondria and chloroplasts were acquired to the eukaryotic cell by endosymbiosis from a prokaryotic cell.
question
Who developed the Endosymbiotic Theory?
answer
Lynn Marguilis
question
Why are microorganisms important for vital activities?
answer
Essential for environmental health
Normal flora keeps you healthy
question
What is normal flora?
answer
Bacteria that is good in one place but bad in another. 500-1000 species of bacteria reside in and on the body. Bacteria outnumber cells 10:1
Ex: E. Coli
question
Why is nitrogen important for DNA?
answer
Nitrogen Fixation
question
Why did the biosphere not work?
answer
There was too much bacteria taking up all the oxygen
question
Antony Van Leeuwenhoek
answer
improved microscopy
Increased magnification 50-300x
question
What is spontaneous generation?
answer
the belief that living organisms can develop from non-living matter
question
Who challenged spontaneous generation and what did he do?
answer
Fransesco Redi challenged spontaneous generation and he did this with the meat and maggots experiment
question
Who tried to disprove Redi? What did he do?
answer
John Needham- he used broth
question
Who disproved Neeham?
answer
Spallanzani disproved Neehams experiment because he found a flaw in it.
question
What did Louis Pasture do?
answer
He created the S-curved flask to trap bacteria, but it still allowed oxygen in
question
What is Koch's Postulate?
answer
1. Present in every case of the disease. absent in healthy organisms
2. Must be isolated and grown in pure culture
3.Same disease must result upon infection of healthy organism
4.Same microorganism must be isolated again
question
Why was gelatin an issue when doing cultures?
answer
Some bacteria eat gelatin
question
What are some application of microbiology?
answer
Sewage Treatment
Bioremediation (ex. oil)
Produce useful products (ex. insulin, ethanol, amino acids, pesticides)
Genetic Engineering
Food (lactic acid, fermentation reactions)
question
Rank microorganisms smallest to largest
answer
virus, bacteria, protist, eurkaryote
question
How can viruses be seen?
answer
Through an electron microscope
question
Resolution
answer
the ability to distinguish between separate objects
question
Contrast
answer
light intensity difference between a sample and its background
question
Light Microscope
answer
Any microscope that uses light
question
Ocular Lens
answer
the lens that is looked through
question
Objective Lens
answer
One near the slide
question
Parfocal
answer
describes the microscope staying relatively focused as magnification increases
question
Parcentric
answer
slide remains centered as magnification increases
question
Bright Field Microscopy
answer
the image is darker than the background. Lenses are causing convergence. The convex lens focus the light (focal point), distance between the lens and F is the focal length
question
Resolving Power
answer
the minimum distance between 2 objects with them still observed as separate entities. As resolution becomes better, resolving power decreases
question
What factors impact resolutions path of light? (resolution dependent on)
answer
Quality and size of lens
Oil Immersion
Wavelength
question
Numerical Aperture
answer
A measure of the cone of light entering into the objective lens
question
Working Distance
answer
distance between the edge of the objective lens and the surface of the specimen
question
Relationship between oil and glass
answer
They have the refractive index
question
Wavelengths relation to resolution
answer
Short wavelengths increase resolution because they can fit where longer wavelengths cant
question
Average wavelength for visible light
answer
about 500 nm
question
What are stains composed of?
answer
A chromophore
Charged salt- negative dye = acidic pH
positive dye = basic pH
question
Which type of dye is used as a negative stain?
answer
Acidic
question
What do stains do?
answer
Increase visibility
Accentuate morphological features
Preserve specimens for future study (heat)
question
Heat fixation
answer
The internal and external cell structures are preserved. This kills the organism, inactivates the enzymes, toughens cell structures.
question
Simple Stains
answer
usually a basic dye, stains all bacteria the same color
question
Differential Stains
answer
Distinguishes between different types of bacteria
Gram stain and Acid Fast stain
question
The Gram Stain
answer
Step 1: Add crystal violet, primary stain and makes everything purple
Step 2: Add iodine, mordant, makes everything bigger
Step 3: Alcohol Wash, decolorizes
Step 4: Add Safranin, counterstain
question
What makes something Gram+ or Gram-
answer
Gram positive indicates a thick cell wall, the crystal violet and iodine mixture is not able to escape from the thick peptidoglycan layer. The opposite is true for Gram-
question
Acid Fast Staining
answer
Acid fast is bacteria containing numerous waxy lipids (mycolic) in their cell walls. 1. Carbolfuchion and heat 2. Decolorize by acid alcohol 3. Counterstain Methalyne Blue
question
Special Staining
answer
Used for staining specific structure inside/outside of the bacterial cell
question
Moellar Stain
answer
A type of endospore stain
1. Carbolfushion and heat
2. decolorize
3. Counterstain with Methalene Blue
question
Schaeffer-Fulton Stain
answer
A type of endospore stain
1. Malachite Green + heat
2. Decolorize
3. Safranine counterstain
question
Capsule Stain
answer
A negative stain
India ink is used which is an acidic dye
question
Flagella Stain
answer
A mordant is used to make them appear thicker
question
Dark Field Microscope
answer
Staining not required
Dark background, bright organism
collects only the light reflected and refracted by the ORGANISM
This is used for eukaryotic cells and larger bacteria
question
Phase Contrast Microscope
answer
No staining is required
Increases contrast by slowing down some wavelengths
Good for prokaryotes
Has 2 types of rings- annular: directs light around and through the specimen
phase: increase the contrast of light waves by speeding them up
question
Fluorescence Microscopes
answer
UV light source
Excites fluorochromes
Fluorescent dyes
question
Confocal Microscopy
answer
Laser examines 3D objects in multiple planes by a computer
Normally fluorescently stained
question
Electron Microscopy
answer
Uses electro magnetic lenses and electrons
Magnifies 10,000-100,000 times
question
Transmission Electron Microscopy
answer
Must be used under a high vacuum because air deflects
Denser regions appear darker due to more electron scattering
question
Sample Preparation for TEM
answer
Sample must be embedded, dehydrated, soaked in plastic
Negative stain is possible with TEM as well as shadowing and freeze etching
question
TEM vs Scanning EM
answer
TEM: radiation passing THROUGH a sample
SEM: electrons released from the sample SURFACE
question
Scanning Probe Microscopes
answer
Most powerful
The surface is so sharp, it can touch individual atoms
question
Shape of a coccus bacteria
answer
Round
question
Shape of a bacillus bacteria
answer
Rod
question
Shape of a Spirillum bacteria
answer
wavy
question
Shape of a coccobacillus bateria
answer
round and rod
question
Shape of a Vibrio bacteria
answer
comma shaped, uncommon
question
Shape of a spirochete
answer
spiral, uncommon
question
What is a chain
answer
Cell arrangement where there is a single chain in one plane
question
What is a packet
answer
Cell arrangement where there are 3-D clumps in two planes
question
What is a cluster
answer
Cell arrangement where the bacteria are in several planes at random
question
What is the composition of the cytoplasmic membrane?
answer
It is made up of a bilayer of phospholipids. It is amphipathic- there is a different chemical feature on both sides. There is also a lipid bilayer with hydrophilic heads and hydrophobic tails
question
What is the fluid mosaic model?
answer
The word fluid tells us that the membrane is not static, it can more and adjust or else cells pop. It has LATERAL movement and rotation. Mosaic tells us it is not uniform throughout the membrane.
question
What is flip-flop?
answer
It is a rare occurance when the fluid mosaic model moves up and down. The enzyme that makes this happen is flippase. The reason this is rare is because there is a lot of resistance from the non-polar tails to move to the other size of the cell
question
Describe an Integral protein
answer
Goes through both sides
Makes up 70-80% of protein in the cytoplasmic membrane
Not easily extractable
Insoluble in water
Have some hydrophilic regions
question
Describe a Peripheral protein
answer
On the inside or outside of the membrane but never both. If on the inside they are normally helping another protein and if they are on the outside they are working as receptors
20-30%
Easily Isolated
Soluble in Water
May attach to integral proteins
question
What is true about both a peripheral protein and a integral protein?
answer
The both function as receptors for cell signaling. Both may interact with cell wall. Both are transporters of nutrients
question
Functions of the cytoplasmic membrane
answer
Selective Barrier
Site of Transport Systems
Site of Crucial metabolic processes
Site for special receptors to decent environmental conditions
question
What compounds are passive transport limited to?
answer
H2O, O2, CO2, and small nonpolar molecules
question
Describe Facilitated Diffusion
answer
Controlled by shape, depends on a concentration gradient, less important in prokaryotes
question
Describe the two types of active transport
answer
Primary- utilizes ATP and are uniporters
Secondary- utilized gradients and are symporters and antiporters
question
Primary Active Transport
answer
ATP Binding Cassette Transports
Found in bacteria, archaea, and eukaryotes. If it is gram negative the protein will attach to the periplasm but if it is gram positive it will attach to the lipids
question
Secondary Active Transport
answer
The proton motive force is used here which is the respiratory chain in the membrane pumps protons out setting up a concentration gradient
question
What are the 3 types of electrochemical gradients?
answer
Uniport- 1 thing, 1 direction
Symport- 2 things 1 direction
Antiport- 2 things, opposite directions
question
What are the steps of phosphorylation?
answer
PEP donates phosphate to E1, pyruvate is left over
E1 is going to pass the phosphate to HPr
Phosphate goes E2a and then to e2b
Then it is passed to glucose
E2c is the transmembrane protein to where the glucose can get in but not out without the phosphate (ex. ticket booth), Glucose + phosphate = glucose 6-P
question
What are siderophores?
answer
compounds secreted by bacteria that scavenge for iron and facilitates its uptake. Iron is brought back to the bacteria and absorbed.
question
Describe ABC when it comes to iron transporters
answer
siderophores sit in the periplasm once in the cell
once it gets into the cytoplasmic membrane it pulls the iron into the cell against its gradient
the cell releases iron from the siderophore, making it able to be used
question
What are some environmental hardships cells can go through
answer
changes from aqueous to hot and dry
Isotonic to hypertonic or hypotonic
question
What are mycoplasma?
answer
They live in environments that are friendly to their outer membranes. They use hopanoids to deal with turgor pressure
They DO NOT handle environmental changes well!!
question
What is peptidoglycan?
answer
Strands of polysaccerides that are weaved together of the cell membrane. This is unique to bacteria. This weaving provides strength to the cell wall. A tetra peptide provides the crosslinking
question
What are some functions of the cell wall?
answer
Cell Shape
Protection
Nutrition
Temperature
question
What is the backbone of the cell wall?
answer
Alternating Monomers of NAG and NAM which pack into each other in numerous layers
question
How are NAG and NAM related to glucose?
answer
The OH is replaced with an acetyl group
NAM picks up the acetyl group
NAG picks up the acetyl group as well as a lactyl group
question
Describe Gram - cell wall
answer
Has DAP
Has direct D-ala binds to Dap
Starts link with D-ala
Very thin cell wall, about 2-3 layers
Periplasm is more defined
Has 2 periplasms
question
Describe Gram + cell wall
answer
Has L-lysine
Does not have a direct link. 5 glycine residues in a row connect D-ala to L-lysine. This is the peptide interbridge called penta glycine
Starts link with D-ala
Thick cell wall, 30 or more layers
Periplasm is harder to see
Does not have an outer membrane
Only 1 periplasm
More resistant to osmotic pressures
Has teichoic and lipteichoic acids
question
What are tehichoic and lipteichoic acids?
answer
They are anchoring compounds in a Gram + cell wall. They add additional support to keep the peptidoglycan layers toether. Teichoic is within the cell wall and lipoteichoic is between the cell wall and the cell membrane. They carry a lot of negative charge
question
What is the LPS?
answer
The LPS is a lipid attached to a polysaccharide or series of sugars.
question
What 3 areas can the LPS be broken up into?
answer
The lipid- disaccharide of glucosamine with 3 FA attached
The Core Polysaccharide- Carbohydrates attached to lipid by KDO
0-Specific Polysaccharide- Species and strain specific
question
What is an endotoxin?
answer
When the macrophages in the bodies immune system target the LPS, it can tear apart the lipid A from the sugar tail, and if the body doesn't handle it it is very toxic, like anaphylactic shock
question
What is endotoxin's benefit to bacteria?
answer
It works as a protective layer
It functions as virulence (survival in humans)- rise in temperature can be a better environment, breakdown of cells is food. It confers negative charge in the bacteria
question
What is a channel protein?
answer
diffusion of small hydrophilic molecule, can be different sizes based on selective entry of differently sized molecules
question
What is Braun's Lipoprotein?
answer
Connects the outer membrane to the cell wall. Works kind of like techoic acid. It really is focused on anchoring the outer membrane.
question
What does the ethanol do in the Gram staining process?
answer
It dehydrates the membrane!
question
What is glycosidase?
answer
It breaks down the cell wall of bacteria in your eye (Lysozyme). It breaks down the sugar linkages in peptidoglycan and breaks the bonds between NAG and NAM
question
What are beta-lactam antibiotics?
answer
An example of these antibiotics is penicillin. These type of antibiotics do NOT break down the cell wall, but they prevent the cell wall from growing. This antibiotic prevents cross linking. The weakened cell wall then ruptures and falls apart.
question
What are protoplasts?
answer
Protoplasts are Gram + bacteria that do not have a cell wall, the cell membrane of this remains in tact. Protoplasts are sensitive to osmotic changes
question
What are spheroplasts?
answer
they are gram negative cells without the cell wall. The cell membrane and the outer membrane are still in tact
question
What is special about the mycobacterium's cell wall?
answer
The mycobacterium have an additional layer with mycolic acids. These are anchored by arabinogalactins to the peptidoglycan layer. There can also be a capsule on this bacteria. That gives the bacteria 4 layers of protection. This is why it is so hard to treat tuberculosis. To the hydrophobic nature of mycobacterium, it will always stain gram- even when its gram+, so acid fast staining is used instead
question
What are components of the internal prokaryotic cell structure?
answer
Storage Granules- "inclusion bodies"
Organic Material
Inorganic Material- magnetosomes
Gas vacuoles
Nucleoid
Plasmids
Ribosomes
question
Why are gas vacuoles important in prokaryotic cell structure?
answer
They are important for floating. In a bacteria like cyanobacteria, the gas collects from the environment to create a gas balloon to float up and collect more energy
question
Why are nucleoids important in prokaryotic cell structure?
answer
They are where genetic information is organized. They are generally circular geneomes comprised of just one chromosome.
question
Why are plasmids important in prokaryotic cell structure?
answer
Plasmids are small portions of DNA that can be exchanged bacteria to bacteria
question
Why are ribosomes important for prokaryotic cell structure?
answer
Since the ribosomes are not bound by an envelope, everything can happen at the membrane which makes the process really fast
question
What are some components of the external structure of prokaryotes?
answer
Glycocalyx
Fimbriae and Pili
Flagella
question
What is the glycocalyx?
answer
it is a sugar coat on the outside of the prokaryote. It acts like an invisibility coat and is sticky. There are 2 types: capsule and slime layer. The capsule is tightly attached and organized, the slime layer is loosely attached and unorganized.
question
What is the function of pilli and fimbriae?
answer
Pilli- genetic exchange
Fimbriae- just attachments, just kind of there
question
What are the patterns of arrangement for flagella?
answer
Monotrichous- only one flagella on either the left or right side
Amphitrichous- one flagella on both sides
Lophotrichous- a tuffed piece on one or both sides
Peritrichous- flagella all over
question
What is the structure of the flagella?
answer
Basal Body --> Hook --> Filament
question
What is the filament?
answer
It is the tail of the flagella and it coils to leave a hollor center
question
What is the hook?
answer
The hook connects the filament to the basal body
question
What is the Basal Body?
answer
anchors flagella into the cell wall and cytoplasmic membrane, it gives the filament the ability to move
question
What is the difference between a flagella in gram + and gram -
answer
In gram positive there is only one set of rings (M and S), and they sit in the membrane. The hook goes through the peptidoglycan.
In gram - there are two sets of rings: (M and S: P and L). The M and S sit in the membrane, the hook is attached to the outer membrane, and the P goes through the peptidoglycan and the L goes through the outer membrane
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question
What is microbiology?
answer
Microbiology is the study of organisms which are usually seen by a microscope, not the unaided eye.
question
Prokaryotic vs. Eukaryotic
answer
Prokaryotic cells came into existence before the eukaryote. They do not have membrane bound organelles or a nucleus. Eukaryotic cells have a nucleus and membrane bound organelles
question
Carl Woese
answer
He created Domain, which is used as a classification system. It showed 2 distinct types of groups, Bacteria and Archaea
question
Prokaryotes
answer
Majority have cell wall with peptidoglycan. Reproduce by binary fission. About 0.3-5 nanometers.
question
Significance of Cyanobacteria
answer
produces significant amounts of oxygen; photosynthetic
question
Archaea
answer
Distinguished from bacteria by unique rRNA gene sequences. Lack peptidoglycan in cell walls. Have unique membrane lipids. Many live in extreme environments (hydrothermal vents, dead sea)
question
Protozoans
answer
unicellular, motile, sexual and asexual reproduction
ex: phytoplankton (photosynthetic)
question
Algae
answer
unicellular and multicellular
photosynthetic
question
Fungi
answer
unicellular and multicellular
Ex: yeast
question
Multicellular Parasites
answer
Helminths- parasitic worms
ex: roundworms, flatworms, flukes
question
Are virus' considered organisms
answer
No, they are considered infectious agents
question
Viruses
answer
Obligate intracellular agent
Consists of either DNA or RNA, surrounded by a protein coat
question
Viroid and Virusoids
answer
Consist of only RNA; no protein coat
question
Prions
answer
consists only of protein, no DNA or RNA
ex: Mad cow disease
question
Why did RNA exist before DNA?
answer
RNA was first because it could store information and was catalytic and DNA is NOT catalytic, only a storage molecule
question
The Endosymbiotic Theory
answer
The theory that states that mitochondria and chloroplasts were acquired to the eukaryotic cell by endosymbiosis from a prokaryotic cell.
question
Who developed the Endosymbiotic Theory?
answer
Lynn Marguilis
question
Why are microorganisms important for vital activities?
answer
Essential for environmental health
Normal flora keeps you healthy
question
What is normal flora?
answer
Bacteria that is good in one place but bad in another. 500-1000 species of bacteria reside in and on the body. Bacteria outnumber cells 10:1
Ex: E. Coli
question
Why is nitrogen important for DNA?
answer
Nitrogen Fixation
question
Why did the biosphere not work?
answer
There was too much bacteria taking up all the oxygen
question
Antony Van Leeuwenhoek
answer
improved microscopy
Increased magnification 50-300x
question
What is spontaneous generation?
answer
the belief that living organisms can develop from non-living matter
question
Who challenged spontaneous generation and what did he do?
answer
Fransesco Redi challenged spontaneous generation and he did this with the meat and maggots experiment
question
Who tried to disprove Redi? What did he do?
answer
John Needham- he used broth
question
Who disproved Neeham?
answer
Spallanzani disproved Neehams experiment because he found a flaw in it.
question
What did Louis Pasture do?
answer
He created the S-curved flask to trap bacteria, but it still allowed oxygen in
question
What is Koch's Postulate?
answer
1. Present in every case of the disease. absent in healthy organisms
2. Must be isolated and grown in pure culture
3.Same disease must result upon infection of healthy organism
4.Same microorganism must be isolated again
question
Why was gelatin an issue when doing cultures?
answer
Some bacteria eat gelatin
question
What are some application of microbiology?
answer
Sewage Treatment
Bioremediation (ex. oil)
Produce useful products (ex. insulin, ethanol, amino acids, pesticides)
Genetic Engineering
Food (lactic acid, fermentation reactions)
question
Rank microorganisms smallest to largest
answer
virus, bacteria, protist, eurkaryote
question
How can viruses be seen?
answer
Through an electron microscope
question
Resolution
answer
the ability to distinguish between separate objects
question
Contrast
answer
light intensity difference between a sample and its background
question
Light Microscope
answer
Any microscope that uses light
question
Ocular Lens
answer
the lens that is looked through
question
Objective Lens
answer
One near the slide
question
Parfocal
answer
describes the microscope staying relatively focused as magnification increases
question
Parcentric
answer
slide remains centered as magnification increases
question
Bright Field Microscopy
answer
the image is darker than the background. Lenses are causing convergence. The convex lens focus the light (focal point), distance between the lens and F is the focal length
question
Resolving Power
answer
the minimum distance between 2 objects with them still observed as separate entities. As resolution becomes better, resolving power decreases
question
What factors impact resolutions path of light? (resolution dependent on)
answer
Quality and size of lens
Oil Immersion
Wavelength
question
Numerical Aperture
answer
A measure of the cone of light entering into the objective lens
question
Working Distance
answer
distance between the edge of the objective lens and the surface of the specimen
question
Relationship between oil and glass
answer
They have the refractive index
question
Wavelengths relation to resolution
answer
Short wavelengths increase resolution because they can fit where longer wavelengths cant
question
Average wavelength for visible light
answer
about 500 nm
question
What are stains composed of?
answer
A chromophore
Charged salt- negative dye = acidic pH
positive dye = basic pH
question
Which type of dye is used as a negative stain?
answer
Acidic
question
What do stains do?
answer
Increase visibility
Accentuate morphological features
Preserve specimens for future study (heat)
question
Heat fixation
answer
The internal and external cell structures are preserved. This kills the organism, inactivates the enzymes, toughens cell structures.
question
Simple Stains
answer
usually a basic dye, stains all bacteria the same color
question
Differential Stains
answer
Distinguishes between different types of bacteria
Gram stain and Acid Fast stain
question
The Gram Stain
answer
Step 1: Add crystal violet, primary stain and makes everything purple
Step 2: Add iodine, mordant, makes everything bigger
Step 3: Alcohol Wash, decolorizes
Step 4: Add Safranin, counterstain
question
What makes something Gram+ or Gram-
answer
Gram positive indicates a thick cell wall, the crystal violet and iodine mixture is not able to escape from the thick peptidoglycan layer. The opposite is true for Gram-
question
Acid Fast Staining
answer
Acid fast is bacteria containing numerous waxy lipids (mycolic) in their cell walls. 1. Carbolfuchion and heat 2. Decolorize by acid alcohol 3. Counterstain Methalyne Blue
question
Special Staining
answer
Used for staining specific structure inside/outside of the bacterial cell
question
Moellar Stain
answer
A type of endospore stain
1. Carbolfushion and heat
2. decolorize
3. Counterstain with Methalene Blue
question
Schaeffer-Fulton Stain
answer
A type of endospore stain
1. Malachite Green + heat
2. Decolorize
3. Safranine counterstain
question
Capsule Stain
answer
A negative stain
India ink is used which is an acidic dye
question
Flagella Stain
answer
A mordant is used to make them appear thicker
question
Dark Field Microscope
answer
Staining not required
Dark background, bright organism
collects only the light reflected and refracted by the ORGANISM
This is used for eukaryotic cells and larger bacteria
question
Phase Contrast Microscope
answer
No staining is required
Increases contrast by slowing down some wavelengths
Good for prokaryotes
Has 2 types of rings- annular: directs light around and through the specimen
phase: increase the contrast of light waves by speeding them up
question
Fluorescence Microscopes
answer
UV light source
Excites fluorochromes
Fluorescent dyes
question
Confocal Microscopy
answer
Laser examines 3D objects in multiple planes by a computer
Normally fluorescently stained
question
Electron Microscopy
answer
Uses electro magnetic lenses and electrons
Magnifies 10,000-100,000 times
question
Transmission Electron Microscopy
answer
Must be used under a high vacuum because air deflects
Denser regions appear darker due to more electron scattering
question
Sample Preparation for TEM
answer
Sample must be embedded, dehydrated, soaked in plastic
Negative stain is possible with TEM as well as shadowing and freeze etching
question
TEM vs Scanning EM
answer
TEM: radiation passing THROUGH a sample
SEM: electrons released from the sample SURFACE
question
Scanning Probe Microscopes
answer
Most powerful
The surface is so sharp, it can touch individual atoms
question
Shape of a coccus bacteria
answer
Round
question
Shape of a bacillus bacteria
answer
Rod
question
Shape of a Spirillum bacteria
answer
wavy
question
Shape of a coccobacillus bateria
answer
round and rod
question
Shape of a Vibrio bacteria
answer
comma shaped, uncommon
question
Shape of a spirochete
answer
spiral, uncommon
question
What is a chain
answer
Cell arrangement where there is a single chain in one plane
question
What is a packet
answer
Cell arrangement where there are 3-D clumps in two planes
question
What is a cluster
answer
Cell arrangement where the bacteria are in several planes at random
question
What is the composition of the cytoplasmic membrane?
answer
It is made up of a bilayer of phospholipids. It is amphipathic- there is a different chemical feature on both sides. There is also a lipid bilayer with hydrophilic heads and hydrophobic tails
question
What is the fluid mosaic model?
answer
The word fluid tells us that the membrane is not static, it can more and adjust or else cells pop. It has LATERAL movement and rotation. Mosaic tells us it is not uniform throughout the membrane.
question
What is flip-flop?
answer
It is a rare occurance when the fluid mosaic model moves up and down. The enzyme that makes this happen is flippase. The reason this is rare is because there is a lot of resistance from the non-polar tails to move to the other size of the cell
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Describe an Integral protein
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Goes through both sides
Makes up 70-80% of protein in the cytoplasmic membrane
Not easily extractable
Insoluble in water
Have some hydrophilic regions
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Describe a Peripheral protein
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On the inside or outside of the membrane but never both. If on the inside they are normally helping another protein and if they are on the outside they are working as receptors
20-30%
Easily Isolated
Soluble in Water
May attach to integral proteins
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What is true about both a peripheral protein and a integral protein?
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The both function as receptors for cell signaling. Both may interact with cell wall. Both are transporters of nutrients
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Functions of the cytoplasmic membrane
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Selective Barrier
Site of Transport Systems
Site of Crucial metabolic processes
Site for special receptors to decent environmental conditions
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What compounds are passive transport limited to?
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H2O, O2, CO2, and small nonpolar molecules
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Describe Facilitated Diffusion
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Controlled by shape, depends on a concentration gradient, less important in prokaryotes
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Describe the two types of active transport
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Primary- utilizes ATP and are uniporters
Secondary- utilized gradients and are symporters and antiporters
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Primary Active Transport
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ATP Binding Cassette Transports
Found in bacteria, archaea, and eukaryotes. If it is gram negative the protein will attach to the periplasm but if it is gram positive it will attach to the lipids
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Secondary Active Transport
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The proton motive force is used here which is the respiratory chain in the membrane pumps protons out setting up a concentration gradient
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What are the 3 types of electrochemical gradients?
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Uniport- 1 thing, 1 direction
Symport- 2 things 1 direction
Antiport- 2 things, opposite directions
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What are the steps of phosphorylation?
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PEP donates phosphate to E1, pyruvate is left over
E1 is going to pass the phosphate to HPr
Phosphate goes E2a and then to e2b
Then it is passed to glucose
E2c is the transmembrane protein to where the glucose can get in but not out without the phosphate (ex. ticket booth), Glucose + phosphate = glucose 6-P
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What are siderophores?
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compounds secreted by bacteria that scavenge for iron and facilitates its uptake. Iron is brought back to the bacteria and absorbed.
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Describe ABC when it comes to iron transporters
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siderophores sit in the periplasm once in the cell
once it gets into the cytoplasmic membrane it pulls the iron into the cell against its gradient
the cell releases iron from the siderophore, making it able to be used
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What are some environmental hardships cells can go through
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changes from aqueous to hot and dry
Isotonic to hypertonic or hypotonic
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What are mycoplasma?
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They live in environments that are friendly to their outer membranes. They use hopanoids to deal with turgor pressure
They DO NOT handle environmental changes well!!
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What is peptidoglycan?
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Strands of polysaccerides that are weaved together of the cell membrane. This is unique to bacteria. This weaving provides strength to the cell wall. A tetra peptide provides the crosslinking
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What are some functions of the cell wall?
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Cell Shape
Protection
Nutrition
Temperature
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What is the backbone of the cell wall?
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Alternating Monomers of NAG and NAM which pack into each other in numerous layers
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How are NAG and NAM related to glucose?
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The OH is replaced with an acetyl group
NAM picks up the acetyl group
NAG picks up the acetyl group as well as a lactyl group
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Describe Gram - cell wall
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Has DAP
Has direct D-ala binds to Dap
Starts link with D-ala
Very thin cell wall, about 2-3 layers
Periplasm is more defined
Has 2 periplasms
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Describe Gram + cell wall
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Has L-lysine
Does not have a direct link. 5 glycine residues in a row connect D-ala to L-lysine. This is the peptide interbridge called penta glycine
Starts link with D-ala
Thick cell wall, 30 or more layers
Periplasm is harder to see
Does not have an outer membrane
Only 1 periplasm
More resistant to osmotic pressures
Has teichoic and lipteichoic acids
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What are tehichoic and lipteichoic acids?
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They are anchoring compounds in a Gram + cell wall. They add additional support to keep the peptidoglycan layers toether. Teichoic is within the cell wall and lipoteichoic is between the cell wall and the cell membrane. They carry a lot of negative charge
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What is the LPS?
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The LPS is a lipid attached to a polysaccharide or series of sugars.
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What 3 areas can the LPS be broken up into?
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The lipid- disaccharide of glucosamine with 3 FA attached
The Core Polysaccharide- Carbohydrates attached to lipid by KDO
0-Specific Polysaccharide- Species and strain specific
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What is an endotoxin?
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When the macrophages in the bodies immune system target the LPS, it can tear apart the lipid A from the sugar tail, and if the body doesn't handle it it is very toxic, like anaphylactic shock
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What is endotoxin's benefit to bacteria?
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It works as a protective layer
It functions as virulence (survival in humans)- rise in temperature can be a better environment, breakdown of cells is food. It confers negative charge in the bacteria
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What is a channel protein?
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diffusion of small hydrophilic molecule, can be different sizes based on selective entry of differently sized molecules
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What is Braun's Lipoprotein?
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Connects the outer membrane to the cell wall. Works kind of like techoic acid. It really is focused on anchoring the outer membrane.
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What does the ethanol do in the Gram staining process?
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It dehydrates the membrane!
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What is glycosidase?
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It breaks down the cell wall of bacteria in your eye (Lysozyme). It breaks down the sugar linkages in peptidoglycan and breaks the bonds between NAG and NAM
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What are beta-lactam antibiotics?
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An example of these antibiotics is penicillin. These type of antibiotics do NOT break down the cell wall, but they prevent the cell wall from growing. This antibiotic prevents cross linking. The weakened cell wall then ruptures and falls apart.
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What are protoplasts?
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Protoplasts are Gram + bacteria that do not have a cell wall, the cell membrane of this remains in tact. Protoplasts are sensitive to osmotic changes
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What are spheroplasts?
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they are gram negative cells without the cell wall. The cell membrane and the outer membrane are still in tact
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What is special about the mycobacterium's cell wall?
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The mycobacterium have an additional layer with mycolic acids. These are anchored by arabinogalactins to the peptidoglycan layer. There can also be a capsule on this bacteria. That gives the bacteria 4 layers of protection. This is why it is so hard to treat tuberculosis. To the hydrophobic nature of mycobacterium, it will always stain gram- even when its gram+, so acid fast staining is used instead
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What are components of the internal prokaryotic cell structure?
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Storage Granules- "inclusion bodies"
Organic Material
Inorganic Material- magnetosomes
Gas vacuoles
Nucleoid
Plasmids
Ribosomes
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Why are gas vacuoles important in prokaryotic cell structure?
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They are important for floating. In a bacteria like cyanobacteria, the gas collects from the environment to create a gas balloon to float up and collect more energy
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Why are nucleoids important in prokaryotic cell structure?
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They are where genetic information is organized. They are generally circular geneomes comprised of just one chromosome.
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Why are plasmids important in prokaryotic cell structure?
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Plasmids are small portions of DNA that can be exchanged bacteria to bacteria
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Why are ribosomes important for prokaryotic cell structure?
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Since the ribosomes are not bound by an envelope, everything can happen at the membrane which makes the process really fast
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What are some components of the external structure of prokaryotes?
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Glycocalyx
Fimbriae and Pili
Flagella
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What is the glycocalyx?
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it is a sugar coat on the outside of the prokaryote. It acts like an invisibility coat and is sticky. There are 2 types: capsule and slime layer. The capsule is tightly attached and organized, the slime layer is loosely attached and unorganized.
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What is the function of pilli and fimbriae?
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Pilli- genetic exchange
Fimbriae- just attachments, just kind of there
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What are the patterns of arrangement for flagella?
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Monotrichous- only one flagella on either the left or right side
Amphitrichous- one flagella on both sides
Lophotrichous- a tuffed piece on one or both sides
Peritrichous- flagella all over
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What is the structure of the flagella?
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Basal Body --> Hook --> Filament
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What is the filament?
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It is the tail of the flagella and it coils to leave a hollor center
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What is the hook?
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The hook connects the filament to the basal body
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What is the Basal Body?
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anchors flagella into the cell wall and cytoplasmic membrane, it gives the filament the ability to move
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What is the difference between a flagella in gram + and gram -
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In gram positive there is only one set of rings (M and S), and they sit in the membrane. The hook goes through the peptidoglycan.
In gram - there are two sets of rings: (M and S: P and L). The M and S sit in the membrane, the hook is attached to the outer membrane, and the P goes through the peptidoglycan and the L goes through the outer membrane