BMCB 658: Exam 1 Questions And
Answers
Enzymes function as reaction catalysts in cells. If the enzymes were removed from a
cell, the rate of biochemical reactions would –
decrease
The __________ differentiates amino acids from one another –
side chains attached to the central carbon
Simple sugars are made of which of the following elements? –
Carbon, oxygen, and hydrogen
Even though starch and cellulose contain the same repeating unit of glucose, they are
very different in terms of function. Why? –
The orientations of the glycosidic bond are different
A hydrogen bond can best be described as –
A weak, noncovalent interaction
The difference between an oxidation reaction and a reduction reaction is that oxidation
is the ___________ and reduction is the ______________. –
Loss of electrons; gain of electrons
Water freezing into ice is an example of what type of entropy change –
A decrease in entropy of the system
Hydrogen bonds can form between hydrogen and –
Oxygen or Nitrogen
If a reaction has a ∆H >0 and a ∆S<0, then _______________ and the reaction is
_____________ at all temperatures –
∆G >0; nonspontaneous
In a mammalian cell, the adenine nucleotide concentrations are [ATP]=3.3 mM,
[ADP]=1.2 mM, and [AMP]=0.2 mM. What is the energy charge of this cell? –
0.83
Which of the following molecules will not form hydrogen bonds?
H2O
NH4
CH4
HF
, H3COH –
CH4
How does the strength of hydrogen bonds compare with covalent bonds? –
Hydrogen bonds are much weaker than covalent bonds
Which of the following properties of water are related to its ability to form hydrogen
bonds?
Boiling point
Melting point
Density
Solvent potency
all of the above –
All of the above
The equilibrium constant Keq for the reaction A ↔ B is 1x10-4 at 25°C. If you started
with a solution containing 50.00 mM of A and 50.00 mM of B and let the reaction
proceed to equilibrium, what would the equilibrium concentrations of A and B be? –
[A] = 99.99 mM, [B] = 10.00 µM
Which of the noncovalent interactions is the weakest? –
Van der Waals
The Keq for the reaction A ↔ B +C is 4.55x103 at 25°C. Calculate ∆G˚' for this reaction.
R= 8.314 J/mol K –
-20.9 kJ/mol
The ΔG°' for the reaction A + B ↔ C is 30.64 kJ/mol at 25°C. Calculate ∆G for this
reaction when [A] - 10 mM, [B] = 50mM, and [C] = 100mM. R= 8.314 J/mol K –
26.7 kJ/mol
For the reaction A + B ↔ C + D at 298 K, the change in enthalpy is -5 kJ/mol and the
change in entropy is –
20 J*mol-1*K-1. Below what temperature does the reaction become spontaneous?
- 250 K
The reaction A ↔ B + C has a Keq= 4.5x105 at 298 K. If 25 mM A, 10 mM B, and 2.5
mM C are added to a flask at room temperature, which direction is favored? –
Forward
The reaction A + B ↔ C was allowed to proceed to equilibrium at 298 K. A solution of
0.500 M C was prepared and allowed to reach equilibrium (no A or B was initially
present). At equilibrium, the concentration of C was 10.0 mM. Calculate the ΔG° for this
reaction. R = 8.314 J*mol-1*K-1 –
7.87 kJ/mol
Answers
Enzymes function as reaction catalysts in cells. If the enzymes were removed from a
cell, the rate of biochemical reactions would –
decrease
The __________ differentiates amino acids from one another –
side chains attached to the central carbon
Simple sugars are made of which of the following elements? –
Carbon, oxygen, and hydrogen
Even though starch and cellulose contain the same repeating unit of glucose, they are
very different in terms of function. Why? –
The orientations of the glycosidic bond are different
A hydrogen bond can best be described as –
A weak, noncovalent interaction
The difference between an oxidation reaction and a reduction reaction is that oxidation
is the ___________ and reduction is the ______________. –
Loss of electrons; gain of electrons
Water freezing into ice is an example of what type of entropy change –
A decrease in entropy of the system
Hydrogen bonds can form between hydrogen and –
Oxygen or Nitrogen
If a reaction has a ∆H >0 and a ∆S<0, then _______________ and the reaction is
_____________ at all temperatures –
∆G >0; nonspontaneous
In a mammalian cell, the adenine nucleotide concentrations are [ATP]=3.3 mM,
[ADP]=1.2 mM, and [AMP]=0.2 mM. What is the energy charge of this cell? –
0.83
Which of the following molecules will not form hydrogen bonds?
H2O
NH4
CH4
HF
, H3COH –
CH4
How does the strength of hydrogen bonds compare with covalent bonds? –
Hydrogen bonds are much weaker than covalent bonds
Which of the following properties of water are related to its ability to form hydrogen
bonds?
Boiling point
Melting point
Density
Solvent potency
all of the above –
All of the above
The equilibrium constant Keq for the reaction A ↔ B is 1x10-4 at 25°C. If you started
with a solution containing 50.00 mM of A and 50.00 mM of B and let the reaction
proceed to equilibrium, what would the equilibrium concentrations of A and B be? –
[A] = 99.99 mM, [B] = 10.00 µM
Which of the noncovalent interactions is the weakest? –
Van der Waals
The Keq for the reaction A ↔ B +C is 4.55x103 at 25°C. Calculate ∆G˚' for this reaction.
R= 8.314 J/mol K –
-20.9 kJ/mol
The ΔG°' for the reaction A + B ↔ C is 30.64 kJ/mol at 25°C. Calculate ∆G for this
reaction when [A] - 10 mM, [B] = 50mM, and [C] = 100mM. R= 8.314 J/mol K –
26.7 kJ/mol
For the reaction A + B ↔ C + D at 298 K, the change in enthalpy is -5 kJ/mol and the
change in entropy is –
20 J*mol-1*K-1. Below what temperature does the reaction become spontaneous?
- 250 K
The reaction A ↔ B + C has a Keq= 4.5x105 at 298 K. If 25 mM A, 10 mM B, and 2.5
mM C are added to a flask at room temperature, which direction is favored? –
Forward
The reaction A + B ↔ C was allowed to proceed to equilibrium at 298 K. A solution of
0.500 M C was prepared and allowed to reach equilibrium (no A or B was initially
present). At equilibrium, the concentration of C was 10.0 mM. Calculate the ΔG° for this
reaction. R = 8.314 J*mol-1*K-1 –
7.87 kJ/mol
