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Bio Mid Term


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Absorbance Values are measured in...
Best Fit Line Formula
X Axis
Independent Variable
Y Axis
Dependent Variable
Steps in Using a Spectrophotometer
1. check & set wavelength 2.blank it: zero transmittance w/ left knob. have control in cuvette. place cuvette in holder. turn % transmittance to 100%
Visible Light Range
380nm to 750nm
Absorbance is ______ related to concentration
= (ml dye * concentration stock)/ total vol
Types of pipettes
mohr, serological, volumeric
Cells, tissues and organs are composed mostly of
water and macromolecules
Mammalian liver consists mostly of
soft parenchyma cells
Monomer of proteins
Amino Acids
a mixture consisting of the molecules that have a uniform composition
Methods of separating biological molecules
solubility, chemical affinity, molecular weight, size or structural associations in a cell.
Method used to dissolve a solute
add heat
method used to precipitate a solute
remove heat
______ is used to aggregate proteins out of liver
(NH4)2SO4 (Sodium Sulfate)
Stirring the contents after the addition of sodium sulfate will
precipitate the proteins by breaking up any remaining bonds
Used to test for proteins
Biuret Solution
Biruet reagent will react with
the peptide bonds in proteins
It is important to use _______ when working with bacteria to prevent contamination
aseptic techniques
Growth and survival of microorganisms depend on
an adequate supply of nutrients and a favorable growth environment
Culture Medium
a solution with a low molecular weight that is derived from the enzymatic degradation of complex nutrients; used for their growth and survival
Types of culture mediums
broth (liquid), semi-solid or solid (agar)
Agar is extracted from
population of bacteria
Selective Media
used to inhibit the growth of some kinds of bacteria and increase the growth of others
Maconkey’s Medium
bile salts and dies, is very restrictive- prevents growth of staph and strep. Allows Ecoli and shigella to grow.
why can Ecoli grow in an environment w/ bile salts?
it has evolved in the conditions of the human gut (bile salts are secreted into the intestine to aid in fat digestion)
when counting colonies look for
convex, opaque and solid
Bacteria replicate
asexually through binary fission
Bacteria growth ________ when temperature is increased
why are spices commonly used in foods in tropical climates
prevents bacteria from easily growing on food, they also provide high amounts of essential vitamins, increase bile flow and stimulate digestion
Spices can inhibit
the oxidation of low density of lipoproteins – prevents development of atherosclerosis
Negative Control
tomato without Ecoli or spice
Positive Control
tomato with Ecoli and NO spice
tomato, Ecoli and spice
Living cells are surrounded by
a selectively permeable phospholipid bilayer
Concentration gradient
concentration decreases from a hypertonic enviornment to a hypotonic enviornment
passive movement (no energy is used) of molecules across a membrane
Fundamental Principle of diffusion
the net movement of substances occurs from regions of high concentration (hypertonic) to low concentration (hypotonic)
active transport
ATP is converted into ADP to move molecules across a membrane and against the concentration gradient
Isotonic Equilibrium
Hypertonic vs Hypotonic. if molecules of solute cant move across membrane, solution will in order to create an equilibrium
Albustix Strips
sensitive to the presence of proteins and are used in urinanalysis. Strip will turn green in the presence of proteins.
Silver Nitrate
can be used to test for chloride. The silver nitrate and the chloride ion will react and form a white precipitate.
Barium Chloride
solution reacts with sulfate to form a white precipitate.
changes to blue-black in the presence of starch

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