Biochem 384: Exam 1 Updated Actual Questions And Correct Answers

BIOCHEM 384: EXAM 1 UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS

Question:
1. Fatty acids are amphipathic, meaning that within the
molecular structure,
A. One end is polar and the other is non-polar
B. Both ends interact with water, they are both hydrophilic
C. Both ends repel from water, they are both
hydrophobic
D. One end is negatively charged and the other end is
positively charged

Answer:
A. One end is polar and the other is non-polar

Question:
2. High-throughout DNA sequencing and bioinformatics
have greatly facilitated our ability to study evolutionary
history. Which of the following is correctly defined?
A. A human receptor gene and a mosquito receptor gene
are highly conserved and are called paralogs
B. Glucose-6-phosphate gene sequences from a human
and a chimpanzee are highly conserved and are called
orthologs
C. Glucose-6-phosphate gene sequences from a human
and a chimpanzee are highly conserved and are called
paralogs
D. Steroid receptor gene and globin receptor gene
sequences in humans are highly conserved and are
called orthologs

Answer:
B. Glucose-6-phosphate gene sequences from a human and a chimpanzee are
highly conserved and are called orthologs

Question:
3. A reaction is always spontaneous if
A. The change in free energy, delta G, is positive
B. The change in free energy, delta G, is negative
C. The change in enthalpy is zero
D. Entropy is increased
E. Enthalpy is reduced

Answer:
B. The change in free energy, delta G, is negative

,Question:
4. Hydrogen bond acceptor

Answer:
all electronegative with lone pair electrons and not bonded to hydrogen
The atom, ion, or molecule component of a hydrogen bond which does not
supply the bridging (shared) hydrogen atom.

Question:
5. Hydrogen bond donors

Answer:
all bound to hydrogen, in biochemistry either N or O atoms
N-H, O-H (NOT C-H)
Strong dipole moment and partial positive charge on the hydrogen

Question:
6. The delta G of ATP hydrolysis is -30.5 kJ/mol. Which of the
following reactions are not spontaneous and could be
driven by being couple to hydrolysis of ATP (one ATP
molecule per individual reaction)?
A. Fructose - 6- phosphate <--> fructose + Pi (-15.9
kJ/mol)
B. Dihydroxyacetone phosphate (DHAP) <-->
glyceraldehyde 3 phosphate (GAP) (7.5 kJ/mol)
C. Pyruvate + Pi <--> phosphoenolpyruvate (+31.5 kJ/mol)
D. Glucose + Pi <--> glucose 6 phosphate (+13.8 kJ/mol)

Answer:
B and D

Question:
7. Which of the following differentiates the biochemical
standard state from the standard state when discussing
standard free energy changes?
A. Temperature of 298K
B. Constant pressure of 1atm
C. 1 M concentration of all reactant and products
D. PH of 7

Answer:
D

,Question:
8. How are changes in enthalpy (H) and entropy (S), related
to changes in free energy (G)?
A. Delta G = Delta S - T delta H
B. Delta G = - Delta H + T delta S
C. Delta G = Delta H - T delta S
D. Delta G = Delta S + T delta H

Answer:
C

Question:
9. Given the following common reactions, which are
entropically favored?
2 pyruvate --> glucose
ATP --> ADP + Pi
Glucose 6P -> fructose 6P
6CO2 + 6H20 -> C6H12O6 + 6CO2

Answer:
ATP -> ADP + Pi

Question:
10. Which of the following statements is correct?
A. The overall free energy of a couple reaction is the
difference of the free energies for the individual reactions
B. ATP is rarely used in coupled reactions
C. An exertion is reaction drives an endergonic reaction
in living systems
D. An endergonic reaction drives an exertion is reaction
in living systems

Answer:
C

, Question:
11. Which of the following biochemical reactions are
endergonic?
A. ATP -> ADP + Pi ; Delta G = -30.5 kJ/mol
B. Glutamate + NH4+ -> Glutamine; Delta G = +14.2 kJ/mol
C. L-Malays + NAD+ -> Oxaloacetate + NADH + H+ ; Delta
G = +29.7 kJ/mol
D. Acetyl-CoA + Oxaloacetate + H2O -> Citrate + CoASH
+ H+ ; Delta G= -32.2 kJ.mol
E. Glutamate + NH4+ + ATP -> Glutamine + ADP + Pi ;
Delta G= -16.3 kJ.mol

Answer:
B, C

Question:
12. Which of the following would be an example of
decreasing entropy?
A. Ice melting
B. Flow of ions through a channel from higher ionic
concentration to lower ionic concentration
C. An anabolic pathway
D. A catabolic pathway

Answer:
C. An anabolic pathway

Question:
13. Mutations in adenylate kinase have led to a hyperactive
enzyme that ultimately ends up elevating ADP levels in a
cell.
Calculate the EC (energy charge) given the following
atypical adenylate concentrations fo the cell containing
the mutant adenylate kinase: ATP = 0.5 mM, ADP = 12.2
mM, AMP = 80 uM

Answer:
0.52