BIOC 385 Exam 1 Questions with
verified solutions passed
Calculate the DG value at 25 °C for the reaction converting fumarate to malate, given the
standard change in free energy of this reaction DGº' is -3.8 kJ/mol, the concentration of
fumarate is 0.010 M, and concentration of malate is 0.02 mM. - correct answer ✔✔DG = DG* +
RTlnQ
= -3.8 + (8.315 x 10^-3)(298K) ln (2x10^-5/0.010) = -19.2 kj/mol
Which statement about enzyme structure and function is the most correct?
A. Enzymes increase the rates of reactions without changing the equilibrium constant.
B. Disulfide bonds are required for enzymes to catalyze biochemical reactions.
C. Enzymes are all multi-subunit complexes requiring cofactors, coenzymes, or metal ions.
D. Ribozymes function at higher temperatures than enzymes that are proteins.
E. Enzyme catalyzed reactions take seconds not years because the Keq is increased. - correct
answer ✔✔A. Enzymes increase the rates of reactions without changing the equilibrium
constant.
R is the highly active form of an allosteric enzyme and T is the less active form. What would
happen to the ratio of [T] / [R] if the concentration of a positive allosteric regulator were to
increase?
A. The ratio is increased
B. The ratio is decreased
C. Unchanged ratio
D. Ratio = 1.0
,E. Ratio = 0 - correct answer ✔✔B. The ratio is decreased
[R] is inc by a positive allosteric regulator
[T] is decreased because [R] is inc
[T]<<[R]
[T]/[R] is decreased
The R state is the __ form of an enzyme. - correct answer ✔✔active
T = inactive "tight"
CTP binding to ACTase ___ the fraction of enzyme in the __ state. - correct answer
✔✔decreases, R state
CTP is an allosteric inhibitor to ATPAse, therefore, decreasing the active form.
In the series of reactions shown below, what is(are) the shared intermediate(s)?
Glucose-6-P <---> Fructose-6-P
Fructose-6-p + Pi <--> Fructose-1,6-BP
ATP <---> ADP + Pi
Glucose-6-P + ATP <--> Fructose-1,6-BP + ATP
A. Fructose-6P + Pi
,B. Glucose-6P
C. ATP
D. Fructose-1,6-BP
E. ADP + Pi - correct answer ✔✔A. Fructose-6P + Pi
Using the DGº' values for the reactions shown below, what is the DGº' value for the conversion
of phosphoenolpyruvate to 3-phosphoglycerate in gluconeogenesis?
Phosphoenolpyruvate <--> 2-Phosphoglycerate DGº' = -1.7 kJ/mol 3-Phosphoglycerate <--> 2-
Phosphoglycerate DGº' = +4.6 kJ/mol - correct answer ✔✔-6.3 kJ/mol
Coupled redox reactions consist of two ___ reactions, one of which results in a loss of electrons
(___) and the other results in a gain of electrons (___). An acronym to remember this is ____ -
correct answer ✔✔half, oxidation, reduction, Oil-Rig.
What two factors control the rate of metabolic flux?
A. Substate binding and enzyme catalysis
B. Glucose levels and enzyme activity
C. Substrate levels and enzyme activity
D. Substrate levels and ATP levels. - correct answer ✔✔C. Substrate levels and enzyme activity
Be able to label parts of an energy diagram.
- transitions state
- activation energy
- change in free energy - correct answer ✔✔
The difference between an oxidation reaction and a reduction reaction is that oxidation is the
_____ of electrons and reduction is the ____ of electrons. - correct answer ✔✔LOSS, gain
, If the Gibbs free energy change value for a reaction is less than zero, this reaction is ______. -
correct answer ✔✔exergonic.
—> exer/endo GONIC = refer to relative change in free energy
Thermic refers to heat
Flux is defined as the rate at which metabolites is/are _____. - correct answer
✔✔interconverted
Enzyme active sites are characterized as ______. - correct answer ✔✔a pocket of cleft.
The Biosphere 2 project, in Tucson, Arizona, was an experiment involving a large sealed
terrarium with humans and photosynthetic plants living in balance. Why did the project have to
be interrupted after only a few months? - correct answer ✔✔CO2 levels rose too dangerously
high
In what location of the cell does the Calvin Benson cycle occur?
A. Chloraplast grana
B. Cytoplasm
C. Chloroplast stroma
D. Thylakoid lumen - correct answer ✔✔C. Chloroplast stroma
Put the following five steps of the photosynthetic electron transport system in the correct order
to explain the process required to convert solar energy into chemical energy
- Chlorophyll is photooxidized and transfers an electron to pheophytin
verified solutions passed
Calculate the DG value at 25 °C for the reaction converting fumarate to malate, given the
standard change in free energy of this reaction DGº' is -3.8 kJ/mol, the concentration of
fumarate is 0.010 M, and concentration of malate is 0.02 mM. - correct answer ✔✔DG = DG* +
RTlnQ
= -3.8 + (8.315 x 10^-3)(298K) ln (2x10^-5/0.010) = -19.2 kj/mol
Which statement about enzyme structure and function is the most correct?
A. Enzymes increase the rates of reactions without changing the equilibrium constant.
B. Disulfide bonds are required for enzymes to catalyze biochemical reactions.
C. Enzymes are all multi-subunit complexes requiring cofactors, coenzymes, or metal ions.
D. Ribozymes function at higher temperatures than enzymes that are proteins.
E. Enzyme catalyzed reactions take seconds not years because the Keq is increased. - correct
answer ✔✔A. Enzymes increase the rates of reactions without changing the equilibrium
constant.
R is the highly active form of an allosteric enzyme and T is the less active form. What would
happen to the ratio of [T] / [R] if the concentration of a positive allosteric regulator were to
increase?
A. The ratio is increased
B. The ratio is decreased
C. Unchanged ratio
D. Ratio = 1.0
,E. Ratio = 0 - correct answer ✔✔B. The ratio is decreased
[R] is inc by a positive allosteric regulator
[T] is decreased because [R] is inc
[T]<<[R]
[T]/[R] is decreased
The R state is the __ form of an enzyme. - correct answer ✔✔active
T = inactive "tight"
CTP binding to ACTase ___ the fraction of enzyme in the __ state. - correct answer
✔✔decreases, R state
CTP is an allosteric inhibitor to ATPAse, therefore, decreasing the active form.
In the series of reactions shown below, what is(are) the shared intermediate(s)?
Glucose-6-P <---> Fructose-6-P
Fructose-6-p + Pi <--> Fructose-1,6-BP
ATP <---> ADP + Pi
Glucose-6-P + ATP <--> Fructose-1,6-BP + ATP
A. Fructose-6P + Pi
,B. Glucose-6P
C. ATP
D. Fructose-1,6-BP
E. ADP + Pi - correct answer ✔✔A. Fructose-6P + Pi
Using the DGº' values for the reactions shown below, what is the DGº' value for the conversion
of phosphoenolpyruvate to 3-phosphoglycerate in gluconeogenesis?
Phosphoenolpyruvate <--> 2-Phosphoglycerate DGº' = -1.7 kJ/mol 3-Phosphoglycerate <--> 2-
Phosphoglycerate DGº' = +4.6 kJ/mol - correct answer ✔✔-6.3 kJ/mol
Coupled redox reactions consist of two ___ reactions, one of which results in a loss of electrons
(___) and the other results in a gain of electrons (___). An acronym to remember this is ____ -
correct answer ✔✔half, oxidation, reduction, Oil-Rig.
What two factors control the rate of metabolic flux?
A. Substate binding and enzyme catalysis
B. Glucose levels and enzyme activity
C. Substrate levels and enzyme activity
D. Substrate levels and ATP levels. - correct answer ✔✔C. Substrate levels and enzyme activity
Be able to label parts of an energy diagram.
- transitions state
- activation energy
- change in free energy - correct answer ✔✔
The difference between an oxidation reaction and a reduction reaction is that oxidation is the
_____ of electrons and reduction is the ____ of electrons. - correct answer ✔✔LOSS, gain
, If the Gibbs free energy change value for a reaction is less than zero, this reaction is ______. -
correct answer ✔✔exergonic.
—> exer/endo GONIC = refer to relative change in free energy
Thermic refers to heat
Flux is defined as the rate at which metabolites is/are _____. - correct answer
✔✔interconverted
Enzyme active sites are characterized as ______. - correct answer ✔✔a pocket of cleft.
The Biosphere 2 project, in Tucson, Arizona, was an experiment involving a large sealed
terrarium with humans and photosynthetic plants living in balance. Why did the project have to
be interrupted after only a few months? - correct answer ✔✔CO2 levels rose too dangerously
high
In what location of the cell does the Calvin Benson cycle occur?
A. Chloraplast grana
B. Cytoplasm
C. Chloroplast stroma
D. Thylakoid lumen - correct answer ✔✔C. Chloroplast stroma
Put the following five steps of the photosynthetic electron transport system in the correct order
to explain the process required to convert solar energy into chemical energy
- Chlorophyll is photooxidized and transfers an electron to pheophytin
