Biochemistry 100% complete Question and Answers 2024 Final
Exam
enzyme regulation
1. regulated at allosteric site
2. regulated by modifications like phosphorylation
on vs. off states
negative feedback- product inhibits enzyme
positive feedback- product activates enzyme
oxytocin is example of positive feedback, needs external regulator to eventually stop process
oxidation/reduction
loss/gain of hydrogen atoms, gain/loss of charge
Bronsted-Lowry acid/base
proton donor/acceptor
Lewis acid/base
electron pair acceptor/donor, usually in coordinate covalent bonds
acid/base-dissociation constant
,large Ka/Kb means stronger acid/base
Ka = [H3O+][A-]/[HA]
Kb = [HB+][OH-]/[B]
amphoteric
can act as either acid or base, amino acids
conjugate base of a weak polyprotic acid is always amphoteric
each time a polyprotic acid donates another proton, it becomes a weaker acid
pH
pH = -log[H+], water at 25C has pH = 7
pH + pOH = 14
pKa
pKa = -logKa
lower pKa/pKb is the stronger the acid/base
buffer
weak acid and its conjugate base
, bicarbonate buffer system, carbonic acid and bicarbonate
amino acids
memorize their structure, names, letters, properties, physiological pH
Nonpolar: PI GALVY MWF
"my PI goes to Galveston on mon/wed/fri"
Acidic: DE (negative at physiological pH)
Basic: HRK (positive at physiological pH)
alanine - ala - A
glycine - gly - G
valine - val - V
leucine - leu - L
isoleucine - ile - I
proline - pro - P
phenylalanine - phe - F
tryptophan - trp - W
tyrosine - tyr - Y (10.1)
serine - ser - S
threonine - thr - T
cysteine - cys - C (8)
methionine - met - M
Exam
enzyme regulation
1. regulated at allosteric site
2. regulated by modifications like phosphorylation
on vs. off states
negative feedback- product inhibits enzyme
positive feedback- product activates enzyme
oxytocin is example of positive feedback, needs external regulator to eventually stop process
oxidation/reduction
loss/gain of hydrogen atoms, gain/loss of charge
Bronsted-Lowry acid/base
proton donor/acceptor
Lewis acid/base
electron pair acceptor/donor, usually in coordinate covalent bonds
acid/base-dissociation constant
,large Ka/Kb means stronger acid/base
Ka = [H3O+][A-]/[HA]
Kb = [HB+][OH-]/[B]
amphoteric
can act as either acid or base, amino acids
conjugate base of a weak polyprotic acid is always amphoteric
each time a polyprotic acid donates another proton, it becomes a weaker acid
pH
pH = -log[H+], water at 25C has pH = 7
pH + pOH = 14
pKa
pKa = -logKa
lower pKa/pKb is the stronger the acid/base
buffer
weak acid and its conjugate base
, bicarbonate buffer system, carbonic acid and bicarbonate
amino acids
memorize their structure, names, letters, properties, physiological pH
Nonpolar: PI GALVY MWF
"my PI goes to Galveston on mon/wed/fri"
Acidic: DE (negative at physiological pH)
Basic: HRK (positive at physiological pH)
alanine - ala - A
glycine - gly - G
valine - val - V
leucine - leu - L
isoleucine - ile - I
proline - pro - P
phenylalanine - phe - F
tryptophan - trp - W
tyrosine - tyr - Y (10.1)
serine - ser - S
threonine - thr - T
cysteine - cys - C (8)
methionine - met - M
