BIOCHEMISTRY CERTIFICATION
EVALUATION UPDATED COMPLETE
QUESTIONS AND CORRECT ANSWERS
VERIFIED
●● exothermic/endothermic
Answer: heat exits/enters the system, negative/positive dH
●● entropy
Answer: dS is always positive, disorder of universe tends to increase
●● enthalpy
Answer: dH = dE + PdV, heat
●● Gibbs free energy
Answer: dG = dH - TdS, negative dG means reaction is spontaneous and
favorable, this is determined by both Keq and Q
dG' = - RTlnK'eq
dG = dG' + RTlnQ, Q = Keq but not at any given time
,ATP -> ADP + P, dG = -12
●● activation energy
Answer: energy required to produce the transition state, catalyst/enzyme
stabilize the transition state and reduce Ea without changing dG
higher Ea means slower reaction rate
drawing a reaction coordinate graph
●● enzymes
Answer: physiological catalysts
increase reaction rate so it happens in a biologically relevant time-frame,
not used up in reaction, specific to a reaction (important for regulation)
interact with substrate at active site, always stereospecific and can form
specific stereoisomers from non-chiral molecules
can interact with different substrates that have similar chemical linkages
induced-fit model vs. lock-key model
, dimers have two similar proteins connected by hydrophobic amino acids
or by *disulfide bonds*
heterodimer- two different proteins
homodimer- two identical proteins
common types:
1. kinases takes phosphate group from donor (ATP)
2. phosphatases removes phosphate group
3. phosphorylases adds phosphate group
3. ligases combine two molecules
4. lyases break apart a molecule, form double bond
5. isomerases convert between isomers
6. transferases transfer functional groups from one molecule to another
(sometimes includes kinases and phosphatases)
●● activating enzymes
Answer: *zymogen* is an inactive enzyme that needs to be cleaved
*apoenzyme* is an inactive enzyme that needs a cofactor
phosphorylation can activate/deactivate
allosteric interactions can regulate
EVALUATION UPDATED COMPLETE
QUESTIONS AND CORRECT ANSWERS
VERIFIED
●● exothermic/endothermic
Answer: heat exits/enters the system, negative/positive dH
●● entropy
Answer: dS is always positive, disorder of universe tends to increase
●● enthalpy
Answer: dH = dE + PdV, heat
●● Gibbs free energy
Answer: dG = dH - TdS, negative dG means reaction is spontaneous and
favorable, this is determined by both Keq and Q
dG' = - RTlnK'eq
dG = dG' + RTlnQ, Q = Keq but not at any given time
,ATP -> ADP + P, dG = -12
●● activation energy
Answer: energy required to produce the transition state, catalyst/enzyme
stabilize the transition state and reduce Ea without changing dG
higher Ea means slower reaction rate
drawing a reaction coordinate graph
●● enzymes
Answer: physiological catalysts
increase reaction rate so it happens in a biologically relevant time-frame,
not used up in reaction, specific to a reaction (important for regulation)
interact with substrate at active site, always stereospecific and can form
specific stereoisomers from non-chiral molecules
can interact with different substrates that have similar chemical linkages
induced-fit model vs. lock-key model
, dimers have two similar proteins connected by hydrophobic amino acids
or by *disulfide bonds*
heterodimer- two different proteins
homodimer- two identical proteins
common types:
1. kinases takes phosphate group from donor (ATP)
2. phosphatases removes phosphate group
3. phosphorylases adds phosphate group
3. ligases combine two molecules
4. lyases break apart a molecule, form double bond
5. isomerases convert between isomers
6. transferases transfer functional groups from one molecule to another
(sometimes includes kinases and phosphatases)
●● activating enzymes
Answer: *zymogen* is an inactive enzyme that needs to be cleaved
*apoenzyme* is an inactive enzyme that needs a cofactor
phosphorylation can activate/deactivate
allosteric interactions can regulate
