1 & 2 Flashcards
(30 cards)
major types of bio polymers
polysacc
lipid bylyaer (w/ noncov interactions)
protein
nucleic acid
major class of biomolec
carb
lipids
ama
nucletodies
first & second law of thermodynamics
1st: energy is consergved- neither created or destroyed
2nd: in spontanenous reaction, convert order to disorder
what is enthalpy? delta enthalpy?
heat content of system. a change in syst’s heat content.
what is entropy? gibbs gree energy?
disorder of systenm. a change in gibbs’ free energy determine if rxn is spontanous, not just delta S.
endothermic vs exothermic.
(+) delta H. process absorbs heat from the surrroundigns.
(-) delta h. process release heat from the surroundings.
forward vs reverse rxn
entropy decrease. negative delta S.
entropy <. postiive delta S.
when is a reaction spontaneous or not?
when delta G is negative, spontaneous and exergonic.
when delta is positive, nonspon, endergonic.
what is central dogma?
central dogma said that DNA contains info to synthesize protein.
DNA (replicate) -> to RNA, transcription -> to protein, translation
describe the water structure
O covalently bonded to 2 H, leaving 2 unpaired e-.
AX2E2, tetrahedral geometry
is polar -> (-) to (+)
how is water cohesive and adhesive?
cohesive ‘ H bond. water atracts water, creating a high surface tension.
adhesive ‘ attracts other substances.
list variosu bonding mechanism.
ionic: btw charged particles
van der waal: btw polar, bt uncharged particles
– dip-dip: 2 strongly polar groups
– london dispersion: weaker, shift in e- cloud
interaction btw a dispersion medium, solvent, with a disperse solute
solvation
why is water the best dispersion medium?
can do H bond and electrostatic interactions.
has a high dielectric content = how much a solvent can diminish the elctrostatic interactions btw dissolved ions (water keeping apart NaCl)
exclusion of nonpolar substances from aq solution
hydrobobic effect.
has a strong attraction btw NP regions
e.g protein folding places hydrophobic am.a tucked inside
what happens when you mix oil and water?
hydrophobic molec prefer like moelc, driven by decrease entropy in water
when oil mix w/ hwater, water cages oil and np tails becomes fixed
=> entropy decrae, unfavorable rxn
what is amphiphilic moelc>
can exp both hydropbic and hydrophic interaction
has a polar head that bonds with polar molec
and n[ tail tucked in
lipid bilayer– in a cell membrane. has a ___ layers of phospholipid, ___, ________
are permeable to __ & __ only
double / glycolipid / fatty acids chain
O gas and CO2
water dissociates into __ + ____ as described by the dissociation constant K
H+ , OH-
K= [H+][OH-] over H2O
the ionisation constant of water is? how much at 25C?
Kw = K[H2O] = [H+] x [OH-]
at 25C Kw = 10 ^-14. so [H+] = [OH-] = 10^-7
ph = log[OH-]. T or F?
F. bcs pH = -log [H+]
acid __ proton while base ___ proton.
what if you have wka and H20 buffer?
CH3COOH + H20 -> ___ + ____
donates, accepts.
wka will donates proton to wate rbugger, creating H30+. (conja) (conjb)
AS DESCRIBED BY Ka (acid dissociation constant)
CH3COOH + H20 -> CH3COO- + H30+
pk = -log Ka. Ka = 1o^-pK
T
higher Ka? lower pK?
higher Ka, more likely to ionise acid and donate proton to water buffer
Lower pK, more deproton, stronger Acid
