Studied by 2 people
what is the technique of biochemistry based on
measuring how much light at a specific wavelength is absorbed by the substance
what are the two important principles in spectrophotometry
Lamberts Law and Beers law
lamberts law
the proportion of light absorbed by a medium is independent of the intensity of incident light , this allows different spectrophotometers to produce comparable absorption readings
Beers law
the absorbance of light is directly proportional to both the concentration of the substance absorbing light and the thickness (pathway) of the medium
what is the standardized pathway length
1 cm
how are absorbance and transmittance related
inversly related
Regression
the statistacal relationship between two variables
linear regression
linear approach between a dependent and independent variable
coefficient of determination
r^2
why is r^2 useful
it describes how reliable the equation is in describing the relationship between x and y and is always presented with a regression equation. Ranges 0-1, the closer to 1 the more reliable the regression equation is
what are the classes of lipids
-phospholipids
-triglycerides
-sterols
phospholipids
diglycerid + phosphate group
triglycerides
oils and fatty acids
sterols
steriods
how does the energy content of lipids compare to carbohydrates
2x the energy for the same amount
how do saturated and unsaturated fatty acids compare in energy contents
saturated fatty acids have a higher ebergy content than unsaturated fatty acids due to thier ability to stack evenly and form interactions across chains.
why do mammals have high amounts of saturated fats
a high body temperature keeps saturated fats liquid allowing for more energy efficiency
what are most biological lipids
unsaturated, solid saturated fats would cause things to crack
protein concentrations are determined by
colorimetric or the development of color (spectrophotometric)
gravimetric
extraction based on weight/gravity
what does the addition of a salt do to a biphasic sample
it increases polarity, further seperating the polar and nonpolar layers
polar lipids
hydrophilic
nonpolar lipids
hydrophobic
why is glass used over plastic in labs
hydrophobic properties compared to the hydrophilic properties of plastic
Polypropolene (PP)
cloudy plastic, inert and safe to use with wide variety of compounds (organic)
Polystyrene (PS)
clear plastics not safe to use with organic compounds
most abundant organic molecule on earth
cellulose
what is the structrual polysaccharide in plant cells
cellulose
what emzyme do animals produce to break glucose bonds
amylase
what enzyme is used to break cellulose bonds
cellobiase
what group of enzymes is cellobiase a part of, and why is this group heavily studied
cellulases, being studied for use in biofuel industry
why is the artificial substrate p-nitrophenyl glucopyranoside used in place of glucose
it becomes yellow in stop solution allowing for readings from the spectrophotometer
how does heat effect rate of reactions
heat will speed up the movement of substrate and enzyme molecules leading to more collisons, after a certain point enzymes will begin to denature because of the temperature
how does pH effect rate of reaction
substrate and enzymes interact through positive and negitve charged sides, changes in pH can lead to the enzyme and substrate loosing thier positive and negative charges
how does enzyme concentration effect the rate of the reactions
increasing the enzyme concentrations would allow the reaction to occur quicker but it is limited by the amount of substrates present
how doe sthe substrate concentration effect rate of reaction
increasing the concentration would increase the initial rate of the reaction because there would be more substrates open to enzymes in the beginning
bromelain proteases
digest proteins
TrisEDTA
buffer, pH 8
why is TrisEDTA used in DNA isolation
it has a pH of 8 and DNA is stable in alkiline conditions while RNA is stable in acidic conditions
how does EDTA work
chelates calcium, attatches to Ca+ ions and prevents nucleus from working because metal ions are critical in their functions
why must there be enough cations in solution when doing DNA isolation
to neutralize the negatively charged phosphates that clump DNA together and allows the DNA to interact with the solvent
most abundant organic biomass
cellulose
cellulayze
enzyme that digests cellulose
how does glycogen differ from starch
more branched
how is enzyme activity measured
units
enzyme activity is characteristic of
a purified enzyme
disacharide
2 glucose
a majority of enzymes are
proteins
functional property of enzymes
effectiness or product produced/time
cellubios
2 sugars
Note
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