BIOCHEMISTRY LATEST REVISION
EXAM QUESTIONS AND ANSWERS
Conversion of CO2 to organic compounds by a wide variety of
living organisms is referred to as
A. photoablation.
B. ossification.
C. photosynthesis.
D. sequestration.
E. carbon fixation
E. carbon fixation
Reduced molecules become _____ upon donating an electron
in a redox reaction.
A. saturated
B. bound to oxygen
C. oxidized
D. reduced
C. oxidized
Given equal masses (the same number of moles of a
compound), which phase of matter has the greatest entropy?
Gas
,Which of the following biochemical reactions are endergonic?
A. Acetyl-CoA + Oxaloacetate + H2O ⇒ Citrate + CoASH + H+ ;
ΔG∘
= -32.2 kJ/mol
B. ATP ⇒ ADP + Pi ; ΔG∘
= −30.5 kJ/mol
C. Glutamate + NH4+ + ATP ⇒ Glutamine + ADP + Pi ; ΔG∘
= −16.3 kJ/mol
D. L-Malate + NAD+ ⇒ Oxaloacetate + NADH + H+ ; ΔG∘
= +29.7 kJ/mol
E. Glutamate + NH4+ ⇒ Glutamine; ΔG∘
= +14.2 kJ/mol
D&E
Which statement best describes the relationship between
anabolic and catabolic pathways?
A. Catabolic pathways convert energy-rich compounds into
energy-depleted compounds and are generally associated with
breakdown, whereas anabolic pathways use compounds high
in chemical energy for biosynthesis.
B. Catabolic pathways utilize energy to biosynthetically
construct macromolecules, whereas anabolic pathways break
down energy-rich compounds into energy-depleted
compounds.
, C. Anabolic pathways do not exist naturally in humans.
D. Catabolic pathways require sunlight
A. Catabolic pathways convert energy-rich compounds into
energy-depleted compounds and are generally associated with
breakdown, whereas anabolic pathways use compounds high in
chemical energy for biosynthesis.
Non-metabolic oxidization of pyruvate liberates 1,140 kJ/mol.
If 12.5 ATP molecules are produced by phosphorylation of ADP
from each molecule of pyruvate converted to CO2 and water,
what is the apparent efficiency? (ΔG∘
of ATP hydrolysis is -30.5 kJ/mol.)
33.4%
At standard conditions, a biochemical reaction has a Keq of
4,000. The reaction favors the
products
What is the change in free energy of this reaction, which has
Keq = 4,000?
-20.55 kJ/mol
The sodium-potassium ATPase hydrolyzes ATP to pump two K+
ions inside the cell and three Na+ ions out. This is an example
of energy conversion in which the energy from ATP is
converted to
A. an electrical potential across the cell membrane.
EXAM QUESTIONS AND ANSWERS
Conversion of CO2 to organic compounds by a wide variety of
living organisms is referred to as
A. photoablation.
B. ossification.
C. photosynthesis.
D. sequestration.
E. carbon fixation
E. carbon fixation
Reduced molecules become _____ upon donating an electron
in a redox reaction.
A. saturated
B. bound to oxygen
C. oxidized
D. reduced
C. oxidized
Given equal masses (the same number of moles of a
compound), which phase of matter has the greatest entropy?
Gas
,Which of the following biochemical reactions are endergonic?
A. Acetyl-CoA + Oxaloacetate + H2O ⇒ Citrate + CoASH + H+ ;
ΔG∘
= -32.2 kJ/mol
B. ATP ⇒ ADP + Pi ; ΔG∘
= −30.5 kJ/mol
C. Glutamate + NH4+ + ATP ⇒ Glutamine + ADP + Pi ; ΔG∘
= −16.3 kJ/mol
D. L-Malate + NAD+ ⇒ Oxaloacetate + NADH + H+ ; ΔG∘
= +29.7 kJ/mol
E. Glutamate + NH4+ ⇒ Glutamine; ΔG∘
= +14.2 kJ/mol
D&E
Which statement best describes the relationship between
anabolic and catabolic pathways?
A. Catabolic pathways convert energy-rich compounds into
energy-depleted compounds and are generally associated with
breakdown, whereas anabolic pathways use compounds high
in chemical energy for biosynthesis.
B. Catabolic pathways utilize energy to biosynthetically
construct macromolecules, whereas anabolic pathways break
down energy-rich compounds into energy-depleted
compounds.
, C. Anabolic pathways do not exist naturally in humans.
D. Catabolic pathways require sunlight
A. Catabolic pathways convert energy-rich compounds into
energy-depleted compounds and are generally associated with
breakdown, whereas anabolic pathways use compounds high in
chemical energy for biosynthesis.
Non-metabolic oxidization of pyruvate liberates 1,140 kJ/mol.
If 12.5 ATP molecules are produced by phosphorylation of ADP
from each molecule of pyruvate converted to CO2 and water,
what is the apparent efficiency? (ΔG∘
of ATP hydrolysis is -30.5 kJ/mol.)
33.4%
At standard conditions, a biochemical reaction has a Keq of
4,000. The reaction favors the
products
What is the change in free energy of this reaction, which has
Keq = 4,000?
-20.55 kJ/mol
The sodium-potassium ATPase hydrolyzes ATP to pump two K+
ions inside the cell and three Na+ ions out. This is an example
of energy conversion in which the energy from ATP is
converted to
A. an electrical potential across the cell membrane.
