Biochem fall exam 1 2026
With Complete Solutions
How many ketoses are shown in the figure below? a.
2
b. 0
c. 1
d. 3
e. 4 - correct answer <<<<<correct answer with dettailed pass ✔✔c. 1
Enzymes are potent catalysts because they:
a. are not completely consumed in the reactions they catalyze.
b. increase the equilibrium constants for the reactions they catalyze.
c. are very specific and can prevent the conversion of products back to substrates.
d. lower the activation energy for the reactions they catalyze.
e. drive reactions to completion while other catalysts drive reactions to equilibrium. - correct answer
<<<<<correct answer with dettailed pass ✔✔d. lower the activation energy for the reactions
they catalyze.
ATP can be hydrolyzed into ADP + inorganic phosphate (Pi) with a ΔG° of -30500 J/mol. If, galactose-
1phosphate can be hydrolyzed into galactose + Pi with a ΔG° of -15.3 kJ/mol what is the Gibbs free
energy change for the reaction of galactose + ATP = galactose-1-phospate + ADP? a. 15.2 kJ/mol
b. -15.2 kJ/mol
c. -30484.7 J/mol
d. -45.8 kJ/mol
e. -1520 J/mol - correct answer <<<<<correct answer with dettailed pass ✔✔b. -15.2 kJ/mol
, In the Watson-Crick model of DNA structure (now called B-form DNA):
a. A-T pairs share three hydrogen bonds.
b. G-C pairs share two hydrogen bonds.
c. the 5' ends of both strands are at one end of the double helix.
d. the nitrogenous bases occupy the interior of the double helix.
e. a purine in one strand always hydrogen bonds with a purine in the other strand. - correct answer
<<<<<correct answer with dettailed pass ✔✔d. the nitrogenous bases occupy the interior of the
double helix.
When two carbohydrates are epimers:
a. they differ only in the configuration around one carbon atom.
b. one is an aldose, the other a ketose.
c. one is a pyranose, the other a furanose.
d. they rotate plane-polarized light in the same direction.
e. they differ in length by one carbon. - correct answer <<<<<correct answer with dettailed pass
✔✔a. they differ only in the configuration around one carbon atom.
B-form DNA in vivo is a _____-handed helix, _____ Å in diameter, with a rise of _____ Å per base pair. a.
right; 18; 3.4
b. right; 23; 2.6
c. left; 20; 3.9
d. right; 20; 3.4
e. right; 18; 3.6 - correct answer <<<<<correct answer with dettailed pass ✔✔d. right; 20; 3.4
In a plot of 1/Vo against 1/[S] for an enzyme-catalyzed reaction, the presence of a competitive inhibitor
will alter the:
a. pK of the plot.
b. intercept on the 1/[S] axis.
c. curvature of the plot.
d. Vmax.
With Complete Solutions
How many ketoses are shown in the figure below? a.
2
b. 0
c. 1
d. 3
e. 4 - correct answer <<<<<correct answer with dettailed pass ✔✔c. 1
Enzymes are potent catalysts because they:
a. are not completely consumed in the reactions they catalyze.
b. increase the equilibrium constants for the reactions they catalyze.
c. are very specific and can prevent the conversion of products back to substrates.
d. lower the activation energy for the reactions they catalyze.
e. drive reactions to completion while other catalysts drive reactions to equilibrium. - correct answer
<<<<<correct answer with dettailed pass ✔✔d. lower the activation energy for the reactions
they catalyze.
ATP can be hydrolyzed into ADP + inorganic phosphate (Pi) with a ΔG° of -30500 J/mol. If, galactose-
1phosphate can be hydrolyzed into galactose + Pi with a ΔG° of -15.3 kJ/mol what is the Gibbs free
energy change for the reaction of galactose + ATP = galactose-1-phospate + ADP? a. 15.2 kJ/mol
b. -15.2 kJ/mol
c. -30484.7 J/mol
d. -45.8 kJ/mol
e. -1520 J/mol - correct answer <<<<<correct answer with dettailed pass ✔✔b. -15.2 kJ/mol
, In the Watson-Crick model of DNA structure (now called B-form DNA):
a. A-T pairs share three hydrogen bonds.
b. G-C pairs share two hydrogen bonds.
c. the 5' ends of both strands are at one end of the double helix.
d. the nitrogenous bases occupy the interior of the double helix.
e. a purine in one strand always hydrogen bonds with a purine in the other strand. - correct answer
<<<<<correct answer with dettailed pass ✔✔d. the nitrogenous bases occupy the interior of the
double helix.
When two carbohydrates are epimers:
a. they differ only in the configuration around one carbon atom.
b. one is an aldose, the other a ketose.
c. one is a pyranose, the other a furanose.
d. they rotate plane-polarized light in the same direction.
e. they differ in length by one carbon. - correct answer <<<<<correct answer with dettailed pass
✔✔a. they differ only in the configuration around one carbon atom.
B-form DNA in vivo is a _____-handed helix, _____ Å in diameter, with a rise of _____ Å per base pair. a.
right; 18; 3.4
b. right; 23; 2.6
c. left; 20; 3.9
d. right; 20; 3.4
e. right; 18; 3.6 - correct answer <<<<<correct answer with dettailed pass ✔✔d. right; 20; 3.4
In a plot of 1/Vo against 1/[S] for an enzyme-catalyzed reaction, the presence of a competitive inhibitor
will alter the:
a. pK of the plot.
b. intercept on the 1/[S] axis.
c. curvature of the plot.
d. Vmax.
