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BIOCHEM2

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winniesmith's version from 2017-01-23 09:37

Section 1

Question Answer
Buffers in interstitail fluid and blood bufferingBicarbonate and carbonic acid (plus aa side chains (albumin))
Major buffers for ICFPhosphate anions, proteins.
Phosphate anionshave high conc. in cells (RBC). Low concentration in plasma and ECF.
ProteinsICF have high levels of proteins containing histidine and other H+ accepting AA (similar to Hb)
Other buffers includeorganic phosphates (ATP and Glucose-6-phospate)
What maintains pHH+ movement out of cell. Most metabolic acids produced within cell pKa<5 (dissociated)
If cells become acidicH+ out Na in
if cells become alkalineBicarbonate out, chloride in
What is the major buffer in Urine (not blood)Ammonium ions. Non volatile acids (not carbonic acids) lost via urine.
what is the pH of urine?5.5-7.0
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Section 2

Question Answer
why do cells need energy?required for biosynthetic reactions.
what do cells need/require to produce energy?energy producing metabolic pathways, requiring 02.
what is the current atmospheric 02 conc?20.93%. Lowest 20million years ago at around 15%. Highest 70mya, at 33%. Drop after cretaceous period, before tertiary.
what is compartmentalismMembrane bound compartments, can be different from surrounding environment.
why is compartmentalism important?Enclosed systems can maintain local conc. ----> high concentrations react more readily.
two types of cellEukaryotes and Prokaryotes
Features of eukaryotesMembrane surrounding a cell nucleus. 10-100um diameter. Organelles- ER, Golgi, mitochondria, lysosomes, peroxisomes.
Features of prokaryotesLack membrane structure (apart from outer membrane). 1-10um diameters. Spherodial,rodlike,helical coil. Example; Ecoli
What is taxonomyGross morphology
What is phylogenyEvolutionary history
What are the 3 kingdomsBacteria, Eukaryota, archaea.
EvolutionEvolution is not directed toward a goal. Variation among individuals. Past determines future. Ongoing
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Section 3

Question Answer
What is thermodynamicsStudy of energy.
In thermodynamic terms what is an organism and its surroundingsa system and the rest of the universe.
why is thermodynamics important?to understand and predict metabolic reactions,
What is the 1st law of thermoEnergy is conserved. Energy is neither created nor destroyed.
What is 'energy change'the difference between *heat absorbed by system from surroundings* and *the work done by the system on the surroundings*.
What is the equation for energy changechange(Triangle) U=q-w
U=energy
q=heat
w=work
p=pressure
v=volume
triangle=delta(change)
H=enthalpy
What is heatreflection of random molecular motion
what is workorganised motion= force x distance
Force can begravitational, mechanical, electrical, chemical.
Equation for; work done by expansion of gas (under constant pressure)W= P x triangle V
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P=pressure
V=volume
Enthalpy (H)=H=U+PV
Change in enthalpy=heat =energy change.
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Section 4

Question Answer
what is the 2nd law of thermoEntropy tends to increase. Spontaneous processes are characterised as the conversion of order to disorder.
what is entropydisorder. more energy dispersal- more entropy.
S=Entropy
K(little)BBoltzmann constant
lnWnm. of ways of arranging components in a system.
equation for S=KB x lnW
S can also be determined by measuring heat. Triangle S= Triangle H / T
What is Gibbs free energys usable energy or energy that is available to do work.
G=Gibbs free energy
equation to calculate Gibbs free energyG= H-TS
T= temperature
equation for the change in gibbs free energytriangle G= H- T triangle S.
what does +ve triangleG meanendegonic (use energy)
what does -ve triangleG meanexergonic (releases energy)
What does classical Td apply tooisolated and closed systems.
what is an isolated systemcannot exchange matter or energy with surroundings.
what is a closed system can only exchange energy
what is an open system can exchange both energy and matter. Only reach equilibrium when flow stops (ie. death).
What are high enthalpy,low entropy foods converted intolow enthalpy but high entropy waste products
what does free energy do powers cellular processes which create ordered organisms.
What does the rate of reaction depend onthe actual path through which the reactants are transformed to products. many reactions are spontaneous, most molecular components can potentially react with each other.
What are enzymesbiological catalysts
what do catalysts do increase the rate of reaction without being used up
How do enzymes workthey accelerate biochemical reactions by physically interacting with the reactants and products to provide a more favourable pathway for the transformation of one to the other
What can enzymes not do?cannot promote reactions whose change in free energy values are positive.
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Section 5