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What three factors determine the quality of an optical image?
- Magnification
- Resolution
- Contrast
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What is Snells law and what is it used to determine?
- Snell's Law describes the relationship between the angles and the velocities of the waves(refraction) (helps determine the light ben (cureveture)
- n1xsin(degree1)=n2xsin(unknown degree2)
- n = index of refraction
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What does the index of refraction (alos called refractive index) of a substance refer to?
- n= index of refractions
- the speed of light in a vacuum divided the the velocity of light in that medium.
- Where c is the speed of light and is the phase velocity. It gives the amount ofrefraction which takes place for light passing from one medium to another
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What do the axis,focal lenghts,and focal points of a lens describe?
- axis - where the light rays converge
- focal point
- focal lengh
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What is real image?
- 3 properties
- has phisyical reality
- it is created from converging light rays by a lens (or morror).
- is formed when the object is outside the focal lenght of the lens
- is upside down with respect to the object
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what is virtual image?
- has only an apparent physical reality crated within the eye from diverging light rays fromed inside the focal leght of les
- right side up with respect of the object that forms it
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Difference between real image and virtual image?
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What are the lens sytems in a modern compound microscope called? How do they work together to create the image of the speciment that you view through thr microscope?
- Ocular: create virtual imagge
- Objective: create a real image/reverse the image
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What is the difference between magnification and reolution? What are some ways of improving resolution?
- Magnification: size
- Resoution: Clarity
- can improve by larger angular aperture the more light better resolution
- Immersion oil to minimize refraction to improve image
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Why do we staing microorganisms? What is the difference between direct staining an indirect(negative) staining?
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what do the following prefixes in the metric system mean:
Milli, Micro, and nano?
- 1 Millimeter: mm 1/1000m = 1x10^-3
- 1 Micrometer: um 1/100,000m = 1x10^-6
- 1 nanometer : nm 1/1000,000,000m = 1x10^-9
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How do a transmission electron microscope and a scanning electron microscope differ?
- TEM shoot electron beam through th specimen.
- flat 2 dimensinal
- freeze fracture
- better resolutions
- SEM: is below the specimen back and forth over the specimen / texture of the outside
- overall: bothe provide different images
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What defines pure culture?
- A culture containing only a single strain or species of microorganism. isolated places of growth. large number of microorganisms all descended form a single individual.
- dilution
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How can we isolate a pure culture in the laboratory?
Streak plate is a petri plate containing some type of steril nutient agar,which is used to seperate the bacteria in a mixed culture so that individuals cells can be isolated from it.
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What do you need to consider in selecting a culture medium to grow a particular microogranism?
- liquid or solid medium
- minimal defined media only nutrients for essential growth
- complex or rich media many nutrients
- carbon sorces
- protein
- notrogen
- aerobic pr arobic media
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Why is agar added to microbilogical culture media and what properties does it have that make it ideal for this purpose?
- Not used by many organisms as a nutrient source
- good solidifing agent
- organisms cant digest it
- easier to handle
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What general characteristics distinquishes between prokaryotic and eukaryotic cells?
eukaryotic larger size
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What are the most common bacterial cell shapes?
- coccus = round
- bacillus = longutudinal weenie
- spirillum =wavy
- spirochete = spiral
- vibro= cashew shaped
- filamentous = long hair like
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What are some of the special cell arrangements that can occur especially among cocci?
- diplococci 2 cells
- cubicpackets 8 cells
- steptococci = long chains
- staphylococci = grape like clusters
- tetrads= 4 cells
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What are three structural components of a bacterial flagellum?
- an ion driven motor: which can provide a torque in either direction;
- hook: a universal joint which transmits motor torque even if it is curved
- filament: a very long structure which acts as a
- propeller, and behaves differently depending on which way the motor turns.
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In what ways does a flagellum confer motility?
propells powered by a moter pwoered by proton motive force
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How can a flagella be arranged on the cell surface?
- protein polymer of repeated subunits
- through a complex of proteins called the hook and basal body.
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What is pilli(fimbriae) and what function does it have?
- porteins straight rods that stick out of the vacteria cells
- not as lod as flagella cells
- helps attach to surfaces
- comen in aquatic environments
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What is a capsule and what functions does it have?
- Usually made up of polysaccharide(some Protein capsules).
- water soluble and nonionic
- helps protec cells from phagoctosis/drying out
- help surface attachment/osmotic pressure barrier
- carbon storage/ develop in harsh times
- cell wall and envelope
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What does glycocalyx refer to?
- a cup shaped structure
- a mat of polysaccharide fibers etending from the cell surface
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What is the basic structure of peptidoglycan?
- polymer of peptide linked chains of amino sugars
- disaccharides called glycan chins corss linked with peptides of four amino acids
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How does the cell wall protect the cell from osmotic damage?
- helps withstand the intracellular turgor pressure that can build up inside the cell
- rigid network of covalent bonds protects cell form osmotic shock
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What are the major differences between gram negative and gram positive bacterial cell walls?
- Gram positive: have a thick cell wall with multiple layers of peptidoglycan.
- Cell membrane with acid
- bacillus ,streptoccocus
- Gram negative: have thin cell wall with one to three layers of peptidoglycan enclosed by an outer membrane (lipopolysaccheride)
- esherichia colie
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What are the major antigens found in association with the cell wall are unique to gram negative or gram positive bacterial cells?
- Gram postitive
- teichoic acid: help retain the gram stain, a reinforement
- s-layer: rigid flexes allows substancs to pass , pore admite molecules
- Gram Negative: lipoprtein and lipopolusaccharide
- murein lipoprotein endotoxin
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What is the structure of the bacterial cell membrane?
- consist of phospholipid bilayer containing lipid sooluble proteins
- hydrophopic fatty acid chains directed inwar,away from water
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What major functions do proteins embedded in the cell membrane have?
- transport
- communicaton
- structural support
- cell defense
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What different types on inclusions are found in the cytoplasm of bacterial cells and what are the functions?
- Storage granules: starch,glycogen polyphosphate, sulfur, and polyhydraxylbutyrate
- Gas Vesicules: provide buoyancy in some aquatic bacteria multiple vesicles stacked together form a gas vacuole
- Carboysomes: protein shells that contain enzymes for barbon dioxide fixation by some bacteria
- Meguetosomes: membrane, endosed, iron containing particles found magnetotactic bacteria
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What characteristics distingquish catabolism form biosynthesis(anabolism)?
- catabolism: breaking down reactions(usuallu release energy ) produce energy
- Biosynthesis(ambolism): building up reactions usually onsume energy must have energy supply.\
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What happens to a protein when it becomes denatured?
disrutpion of protein structure losses its bilogical function
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What are the two chemicals differences between the nucleic acids RNA and DNA?
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What is the difference between exergonic and endergonicm chemical reactions?
- endergonic: non spontaneous requires and external input or energy
- Exergenic: spontaneous releases energy progress reaction
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What is an activaction energy?
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What is a catalyst?
- it increase reation rate
- unalterd by reaction
- catalyst lowers the activtion energy
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What are the two different catergoris of cofactors?
- metal ions: Mg2+, Zn2+, etc
- organic coenzyme: can ve lugged in vitamins
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How are certain cofactors related to vitamins?
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How is an apoenzyme different from a holoenxyme?
- apoenzyme: inactive protein
- holoenzyme: active final product
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What is an active site of an enzyme?
- specific sit where the enzyme can react
- induced fit model
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what is allosteric site?
- all: other
- Steric: solid
- resutl in enxyme slows down use either to control a pathway
- different door way
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What distinguishes competitive and noncompetitive inhibition?
- competitive inhibition: adding more substrate reverses the inhibition
- substrate and inhibitor compete for the active site
- Non-competitive: adding more substrate does not reverse the inhibition
- will bond to the allosteric makes a distortion of the enzyme
- bonding to the allosteric not the active
- overall both slow down activity
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What is feedback inhibition?
- ability to bind to th ebegining and slows down the throenin deaminase
- there for slows metabolic pathway
- helps regulate how muche isoleucine product you want to make
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beriberi
- vitamin b1 thamine deficiency disease
- chonic congestion mucle pain nerve damage
- source rice
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pellagra
- vitamin b3 naicin dificency
- germtitis-fatique, comition , insomnia
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What is a carbohydrate?
- CH2O
- polysaccharides comples
- starches,fibers, sugars
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What is the chemical formula of pentos monosaccharide and a hexos monosaccharide?
- pentos = C5H10O4
- hexos = C6H12O6
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In what ways are two monosaccharides are linked together and what is the resultng chemical bond between them called?
two monosaccharides form a disaccharide through a condensation reaction to form a covalent glycosidic bond
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What type of structural information is represented at each level of protein?
- Primary: amino acid sequence alpha helix
- secondary: bending and folding over short strecthes of the polypetide Beta-strand
- tertiery: benidn and follding over long stretches
- quaternary: arrangements of two or more polypeptide in the protein
- alha and beta
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What is a nucleotide and what three components make up the structure?
- Nucleic acids (both RNA and DNA) are polymers
- made up of monomers called mononucleotide units
- pentose sugar
- nitrogenous base
- phosphate group
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