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76 Cards in this Set
- Front
- Back
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What is a microbe? (2) properties
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- single, celled
- most (not all) visible through microscope |
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microbe- major groups(6)
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- prokaryotes
- eukaroytes - archaea - protist - fungi - (viruses) |
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All cells have cell membrane, why?(3)
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1. boundary
2. osmotic barrier 3. regulate transport |
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Big percentage of cell are what? %? range of ribosomes?
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30% macromolecules
includes 20,000-200,000 ribosomes |
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Membrane mainly consists of what? percentage?
Rest are what? |
70% of membrane is proteins,
rest phospholipids |
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Membrane is what form @ growth temp
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liquid, 2D form
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EX of a amphipathic molecule
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phospha-tidyl-glycerol
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what's inserted to strengthens membrane?
similar to what? |
hopanoids
similiar to cholesterol |
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What part of membrane may vary?
what factors does it depend on(2) |
Lipids
1) growth conditions 2) temperature |
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Archaea's variation that's different from other bacteria(2)?
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lipids with ether linkages
(sometimes monolayer (more rigid) ) |
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Roles of membrane proteins(3)
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1) structural support
2) import and export - acquire nutrients, avoid toxins 3) signal detection |
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Example of Signal detection-
what's the protein name? structure? |
Vibrio cholerae
ToxR protein- transmembrane: parts in/out cell Inside part- does Gene Regulation |
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What's chemotaxis?
how does it do what it does |
"sense of smell"
transmembrane molec: allowed to sense external environment |
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how's ethanol problem of membrane
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it can cross and also interact w/ lipids.
solubilizes the membrane. |
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If genome codes for a lot of transporters what does it signify?
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more complex enivornment = more transporters; sees more changes, lives in more complex environment
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Cell wall is made from what? What's it function(2)?
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made from peptidoglycan
funct: 1) structure 2) shape |
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Why are cell wall not fully cross-linked?(2)
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- for cell wall division or growth, must add new cell wall so must be able to constantly break cross-links
maintain cell fluidity- sometimes not as tight together needs to be able to expand or constrict |
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How is cell wall synthesis started off?
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fructose-6-P creates UDP-NAG and that forms UDP-NAM
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UDP-NAM is added to how many peptides? What's at the end
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5 peptides including 2 D ala-D ala
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What blocks transpeptidation of cell wall synthesis?
how does it do that? what type of cell is target |
Vancomycin
- binds to D-ala D-ala, thus prevents cross-linkages - works on Gram + |
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Prevents release of phosphate of cell wall synthesis
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Bacitracin:
binds to bactoprenol |
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Cell wall synthesis: what binds enyzme for transpeptidation?
name of enyzme - what exactly does it do |
Penicillin
binds active site (blocks cross-linkages) of enzyme, by mimics D ala D ala enzyme: transpeptidase |
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What are the same class antibiotics as Penicillin?(3)
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Ampicillin
methicillin amexicillin |
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Cell wall function(2)
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1) osmotic press resistence
2) maintain shape |
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what cleaves sugar backbone of cell walL? how does it work
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Lysozyme- breaks cell wall and cleaves sugar off
in water: cell burst in sucrose(isotonic) protoplast, rod to circle |
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Characteristics of Gram positive(2)
what phyla? |
- big cell wall
- 30-40 layers - holds stain - firmicutes |
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Characteristics of Gram negative(2)
what phyla |
-wall: 1-2 layers
- has peri-plasmic space and outer membrane |
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LPS has which portions? What part is toxic
ex (2) |
O-antigen, polysaccharide, Lipid A
Lipid A- toxic EX: Salmonella, Shigella |
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What protein tether's outer membrane?
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Braun's lipoprotein
- most abundant protein in E. Coli |
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acid-fast bacteria- what's attached to it
characteristics(3) |
mycolic acids: attach to cell wall
- long and waxy, - restricts transport - excludes chemicals - slow growth ex: Mycobacterium tuberculosis |
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antibiotic targets mycolic acid attachment?
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ethambutol
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membrane of mycoplasmas strengthened by
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sterols
- more resistance to osmotic press |
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Mre B looks like? its effect
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looks like 1) actin
2) delete exp: loses rod shape |
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What gives bacteria shape besides cell wall?
examples(3) |
cytoskeleton
FtsZ- similar to tublin; most dividing cells Mre B: similiar to actin - deletion: no longer rod-shaped - is spiral shaped Crescentin: makes curve shapes, in eukaroytes Caulobacter: has all three cytoskeletons |
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nucleoid: what is it?
what holds it together |
irregular shaped region of prokaroytes containing DNA
- genetic material is localized - ori- tethered to membrane DNA-binding protein holds together |
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Coupled transcription and translation
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membrane- proteins can be tucked right into membrane, no specialized compartment
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define proteome
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all cellular proteins
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Cell division steps (5)
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1) DNA replication
2) cell elongation 3) septum formation 4) completion of septum w/ formation of distinct walls 5) cell separation |
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FtsZ, what does it do (2)
common in what types |
1) forms rings
2) constricts common in bacteria and archaea |
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FtsZ recruits other protein for (3)
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1) regulate timing
2) make new cell wall 3) ensure DNA separated |
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Fts Z mutant, why won't it work
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@ normal temp, works fine. at higher temperature- nonfunctional b/c can't fold properly
- mutant--> cell gets really long but doesn't divide. "makes range narrower! changes conditions in which it grows |
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What are gas vesicles?
what do they provide? made from what what causes deflation Example? |
specialized structures of aquatic bacteria, allows them to float to the surface to get sunlight
provides: buoyancy made from proteins (GsvA) pressure: causes deflation |
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Magnetosomes
what are they? what do they contain what type of bacteria |
membrane enclosed structures that contain Magnetite(Fe3O4)
- orient with magnetic field, doesn't pull them down - swim down to lower O2--> using flagella - anaerobic, find nutrients at lower part of ocean |
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What happens to energy, how is it stored? (2)
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1) atp
2) membrane potential use to power flagella |
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Why is it difficult for nutrients to get into cell (3)
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1) nutrients that are difficult to transport
2) membrane impermeability 3) low concentration of nutrients |
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Solution for nutrients being difficult to transport? (i.e.)
Why would this be bad? (2) |
Hydrolyze extracellularly.
i.e. send amylase out to breakdown starch into smaller molecules BAD: 1) a lot of waste products 2) competition b/t other organisms for the food |
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What if there is a clearing around a molecule, what does that signify? where does it happen?(2)
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cells are secreting amylase- to help breakdown starch around the cell and through the media
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ABC transport
what does it stand for? is it active? name characteristics(3) |
ATP binding cassette. active transport
1) for G+ and G- 2) high affinity 3) molecule specific- utilizes specific binding protein |
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Sugar Transport- AKA?
unique? (2) |
"group translocation"
Unique: 1) its a transport system that's for greater than one molecule( glucose, mannose, mannitol) 2) modifies the substrate as transported--> to keep sugar concentration inside cell low, so that the concentration gradient between the inside/outside is maintained and sugar will continue to move in. |
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In order for cells to grow what do they need? (2)
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Cells need
1. nutrients 2. energy |
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Cells change to stationary phase, why? (2)
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1. lack of nutrients
2. buildup of waste products (inhibitory) |
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Why does rate of cell growth vary?
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1. temp
2. pH 3. type of food or nutrients ( do they get a lot of energy out of it) 4. whether or not they can take in this nutrient |
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Lag phase- cells aren't growing yet, why? (2)
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1. new nutrient- haven't seen it before, must synthesize enyzmes to convert it to central metabolism, transport protein; prepare to grow
2. Station phase- Adapted to non-growing state and takes time to adjust back |
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Short lag phase is from what? (2)
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1. take 1 or 2 cells already in exponential phase and put it on same media
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Station phase decisions, cells are starving, what do they do? (3)
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1. Uptake DNA
a. for food b. to incorporate new trait for better adaptability 2. make a flagella- swim away to find new food 3. sporulation |
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"Long term" stationary phase- characteristics?(3)
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1. increased mutation rate
2. stress-induced response 3. population is STILL dynamic |
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what is catabolite repression?
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to use one carbon source preferentially over another
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Biofilms: definition.
how do they function? (3) |
microbes that grow in communities
1. communication- quorum sensing 2. protection- EPS(exopolysaccharide) 3. attachment- pili |
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what is SASP? what does it do
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small acid-soluble protein:
1. changes dna shape 2. resistant to UV damage splits water--> less water, less risk |
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BT- crystals, what is it?
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bacillus thuringionsis crystalline toxins-
1. insolube in the cell 2. soluble- change in pH of insect causes it to be soluble and larva absorb it and is killed |
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Germination steps (4 pts)
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1. sensing of germinant (food)
a.rehydration- activates enzymes b.rna&protein synthesis c.degradation of SASP 2. growth of cell |
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Secondary metabolites (ex, 2)
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function not totally obvious, not needed for primary growth;
i.e. antibiotics, geosmin |
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Adaptations, two types
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temporary: change in gene expresion
permanent : change in genome - mutations - incorporate other's genes |
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psychrophiles enzymes
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1. decrease in bonding
2. decrease in beta sheets 3. increase in alpha-helices 4. more flexible |
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thermophiles enzymes
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1. increase in bonding
2. increase in charged AA 3. more rigid |
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Amazing facts about conjugation
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1. entire genome may be replicated with patience
2. DNA can be transferred between domains |
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Agrobacterium- what disease do they cause? what do they force plants to make.
what hormones do they include? (3) |
Causes crown gall disease.
Force plants to make opines- similiar to AA and good food growth hormones that cause shooty growth, rooty growth, opines ( Ti plasmid) |
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Agrobacterium- what disease do they cause? what do they force plants to make.
what genes do they include? (2) |
Causes crown gall disease.
Force plants to make opines- similiar to AA and good food. growth hormones that cause shooty growth, rooty growth, genes to create opines( Ti plasmid) |
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BT toxin in plants, how is it introduced? what does it do
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It is introduced via Agrobacterium and it expresses the toxin which increases the resistance to insects
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Plasmids characteristics(4)
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** Self-replicating
naturally occurring in bacteria no necessarily small - extra-chromosomal: not necessary for growth |
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Low-copy # plasmid replication, how does it work? (2)
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1. Its replication is coordinated with chromosome replication
2. ATP-ParM(actin-like): polymerizes into long filaments from the middle make sure the plasmids go to the poles |
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High copy-number plasmids, what happens?
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cell divides- the plasmids are divided by random segregation b/c there's a lot so do not need to worry that one cell will lack
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Regulation of lysogenic or lytic pathway?
how does it go from lysogenic--> lytic |
Repressor protein binds one operator site to block and the other one's is expressed
2. stressful condition-induced: i.e. uv light and phage know cells about to die need to preserve themselves so they know they must break out |
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phage DNA evades endonuclease, how? (3)
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1. bring along own methylase to methylate phage DNA itself quickly before endonuclease cuts it
2. fewer recognition sites- phage is specific for bacteria, so already know restriction site of endonuclease is looking for, these sites are modified 3. increase methylase activity- bringing molecule to enhance activity to quickly methylate it b4 |
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phage DNA evades endonuclease, how? (3)
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1. bring along own methylase to methylate phage DNA itself quickly before endonuclease cuts it
2. fewer recognition sites- phage is specific for bacteria, so already know restriction site of endonuclease is looking for, these sites are modified 3. increase methylase activity- bringing molecule to enhance activity to quickly methylate it b4 |
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Winogradsky column, what's the significance?(3)
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- can keep growing if grown in the column
- recycling of compounds for each other to use - each layer = different species b/c different condition |
