ACS Biochemistry Final Review questions with verified
answers
-------- is the terminal electron carrier of the cytochrome b6f complex. Ans✓✓✓
Plastocyanin (PC)
-------- transfers electrons to plastoquinone. Ans✓✓✓ Photosystem II
---------- complex contains the water-splitting enzyme. Ans✓✓✓ Photosystem II
---------- is a small protein that marks other proteins for degradation Ans✓✓✓
ubiquitin
----------- is the complex that reduces NADP+ Ans✓✓✓ Photosystem I
--------------------, or rate of flow, of metabolites through a pathway requires
knowledge is determined by which enzymes are operating near equilibrium and
which are far from it. Ans✓✓✓ FLUX
"Specific activity" is a measure of protein purity. Which step in this table appears
to have the best improvement in purity? Ans✓✓✓ Size-exclusion
chromatography
A 2-year-old boy with weakness on exertion is found to have a pyruvate
carboxylase deficiency. Which of the following compounds could this child use as
a substrate for gluconeogenesis? Ans✓✓✓ glycerol
,A 24-year-old woman presents with diarrhea and jaundice. Thee patient is
diagnosed with arsenic poisoning. Arsenic is known to inhibit which of the
following enzymes of TCA cycle? Ans✓✓✓ α-ketoglutarate dehydrogenase
A 56-year-old chronic alcoholic has been brought to the emergency room in a
semiconscious state. Blood biochemistry reveals hypoglycemia with a blood
glucose level of 45 mg/dL. Which of the following intermediates of TCA cycle can
be directly converted to phosphoenolpyruvate to trigger the pathway of
gluconeogenesis? Ans✓✓✓ oxaloacetate
A column containing carboxymethyl groups can be used to separate serum
albumin and ribonuclease A. Serum albumin has a pI of 4.9 and Ribonuclease A
has a pI of 9.4. Which one of these 2 proteins will bind to the column if both
proteins are dissolved in a buffer solution with pH=7.0? Ans✓✓✓ ribonuclease A
A defect in lactate dehydrogenase would require the coupling of which enzyme
reaction to that of glyceraldehyde-3-phosphate dehydrogenase in order for
effective gluconeogenesis to proceed? Ans✓✓✓ malate dehydrogenase
A laboratory analysis of isolated mitochondria demonstrates that oxygen
consumption is normal when succinate is added but extremely low when
pyruvate and malate are used. The mitchondria are subsequently shown to have
normal cytochromes but a reduced iron content. The reduced pyruvate/malate
oxidation is due to a defect in which of the following respiratory components?
Ans✓✓✓ NADH dehydrogenase
A metabolic pathway will typically occur in several different cellular
compartments. Ans✓✓✓ FALSE
,A molecule of acetyl-CoA enters the Krebs cycle and the cycle proceeds just until
oxaloacetate is formed. The result is that Ans✓✓✓ two molecules of CO2 are
formed, three molecules of NAD and one molecule of FAD are reduced, and one
molecule of GDP is converted to GTP.
A product is a .............. inhibitor if it inhibits an earlier step in its own
biosynthesis. Ans✓✓✓ FEEDBACK
A protein studied in the lab dissociates from the cell plasma membrane after
treatment with high salt concentrations or changes in pH. What type of protein
could this be? Ans✓✓✓ A peripheral membrane protein.
A transporter protein moves substances X and Y as shown in the diagram. It
moves X down its concentration gradient and Y up its concentration gradient.
What type of transport is this? (THEY MOVE IN OPPOSITE DIRECTIONS) Ans✓✓✓
Secondary active antiport
A true statement concerning phosphofructokinase-1(PFK-1) and fructose-1,6-
bisphosphatase is that Ans✓✓✓ fructose-2,6-bisphosphate is a positive allosteric
regulator of PFK-1 and is a negative allosteric regulator of fructose-1,6-
bisphosphatase.
A well-designed enzyme active site provides which of the following features?
A. Complementarity of shape and chemical nature to the substrate(s).
B. Proximity and correct orientation of substrates and catalytic groups.
, C. Complementarity of shape and chemical nature to the transition state.
Ans✓✓✓ All are correct
Activation of which transporter can increase the concentration of calcium inside
the cell? Ans✓✓✓ CNNM4
ADP activates the formation of pyruvate. Ans✓✓✓ TRUE
All glycerophospholipids have at least one negatively-charged group. Ans✓✓✓
TRUE
All of the following are functions of the tricarboxylic acid cycle in mammals,
EXCEPT Ans✓✓✓ the net synthesis of oxaloacetate from acetyl-CoA.
All of the following statements about cytochromes of the electron transport chain
are true EXCEPT Ans✓✓✓ ANSWER: They all have the same reduction potential
when reduced
When reduced, iron is in the +2 state
They serve as electron carriers in oxidation-reduction reactions
When oxidized, iron is in the +3 state
All of the following statements are true EXCEPT Ans✓✓✓ ANSWER: When
succinate is oxidized, protons are pumped at complex I
answers
-------- is the terminal electron carrier of the cytochrome b6f complex. Ans✓✓✓
Plastocyanin (PC)
-------- transfers electrons to plastoquinone. Ans✓✓✓ Photosystem II
---------- complex contains the water-splitting enzyme. Ans✓✓✓ Photosystem II
---------- is a small protein that marks other proteins for degradation Ans✓✓✓
ubiquitin
----------- is the complex that reduces NADP+ Ans✓✓✓ Photosystem I
--------------------, or rate of flow, of metabolites through a pathway requires
knowledge is determined by which enzymes are operating near equilibrium and
which are far from it. Ans✓✓✓ FLUX
"Specific activity" is a measure of protein purity. Which step in this table appears
to have the best improvement in purity? Ans✓✓✓ Size-exclusion
chromatography
A 2-year-old boy with weakness on exertion is found to have a pyruvate
carboxylase deficiency. Which of the following compounds could this child use as
a substrate for gluconeogenesis? Ans✓✓✓ glycerol
,A 24-year-old woman presents with diarrhea and jaundice. Thee patient is
diagnosed with arsenic poisoning. Arsenic is known to inhibit which of the
following enzymes of TCA cycle? Ans✓✓✓ α-ketoglutarate dehydrogenase
A 56-year-old chronic alcoholic has been brought to the emergency room in a
semiconscious state. Blood biochemistry reveals hypoglycemia with a blood
glucose level of 45 mg/dL. Which of the following intermediates of TCA cycle can
be directly converted to phosphoenolpyruvate to trigger the pathway of
gluconeogenesis? Ans✓✓✓ oxaloacetate
A column containing carboxymethyl groups can be used to separate serum
albumin and ribonuclease A. Serum albumin has a pI of 4.9 and Ribonuclease A
has a pI of 9.4. Which one of these 2 proteins will bind to the column if both
proteins are dissolved in a buffer solution with pH=7.0? Ans✓✓✓ ribonuclease A
A defect in lactate dehydrogenase would require the coupling of which enzyme
reaction to that of glyceraldehyde-3-phosphate dehydrogenase in order for
effective gluconeogenesis to proceed? Ans✓✓✓ malate dehydrogenase
A laboratory analysis of isolated mitochondria demonstrates that oxygen
consumption is normal when succinate is added but extremely low when
pyruvate and malate are used. The mitchondria are subsequently shown to have
normal cytochromes but a reduced iron content. The reduced pyruvate/malate
oxidation is due to a defect in which of the following respiratory components?
Ans✓✓✓ NADH dehydrogenase
A metabolic pathway will typically occur in several different cellular
compartments. Ans✓✓✓ FALSE
,A molecule of acetyl-CoA enters the Krebs cycle and the cycle proceeds just until
oxaloacetate is formed. The result is that Ans✓✓✓ two molecules of CO2 are
formed, three molecules of NAD and one molecule of FAD are reduced, and one
molecule of GDP is converted to GTP.
A product is a .............. inhibitor if it inhibits an earlier step in its own
biosynthesis. Ans✓✓✓ FEEDBACK
A protein studied in the lab dissociates from the cell plasma membrane after
treatment with high salt concentrations or changes in pH. What type of protein
could this be? Ans✓✓✓ A peripheral membrane protein.
A transporter protein moves substances X and Y as shown in the diagram. It
moves X down its concentration gradient and Y up its concentration gradient.
What type of transport is this? (THEY MOVE IN OPPOSITE DIRECTIONS) Ans✓✓✓
Secondary active antiport
A true statement concerning phosphofructokinase-1(PFK-1) and fructose-1,6-
bisphosphatase is that Ans✓✓✓ fructose-2,6-bisphosphate is a positive allosteric
regulator of PFK-1 and is a negative allosteric regulator of fructose-1,6-
bisphosphatase.
A well-designed enzyme active site provides which of the following features?
A. Complementarity of shape and chemical nature to the substrate(s).
B. Proximity and correct orientation of substrates and catalytic groups.
, C. Complementarity of shape and chemical nature to the transition state.
Ans✓✓✓ All are correct
Activation of which transporter can increase the concentration of calcium inside
the cell? Ans✓✓✓ CNNM4
ADP activates the formation of pyruvate. Ans✓✓✓ TRUE
All glycerophospholipids have at least one negatively-charged group. Ans✓✓✓
TRUE
All of the following are functions of the tricarboxylic acid cycle in mammals,
EXCEPT Ans✓✓✓ the net synthesis of oxaloacetate from acetyl-CoA.
All of the following statements about cytochromes of the electron transport chain
are true EXCEPT Ans✓✓✓ ANSWER: They all have the same reduction potential
when reduced
When reduced, iron is in the +2 state
They serve as electron carriers in oxidation-reduction reactions
When oxidized, iron is in the +3 state
All of the following statements are true EXCEPT Ans✓✓✓ ANSWER: When
succinate is oxidized, protons are pumped at complex I
