BSC 2010 CHAPTER 9 EXAM QUESTIONS
WITH CORRECT ANSWERS
The rate of cellular respiration is regulated by its major product, ATP, via feedback
inhibition. As the diagram shows, high levels of ATP inhibit phosphofructokinase (PFK),
an early enzyme in glycolysis. As a result, the rate of cellular respiration, and thus ATP
production, decreases. Feedback inhibition enables cells to adjust their rate of cellular
respiration to match their demand for ATP. - Answer- ATP levels would fall at first,
decreasing the inhibition of PFK and increasing the rate of ATP production.
Under anaerobic conditions (a lack of oxygen), glycolysis continues in most cells
despite the fact that oxidative phosphorylation stops, and its production of NAD+ (which
is needed as an input to glycolysis) also stops. The diagram illustrates the process of
fermentation, which is used by many cells in the absence of oxygen. In fermentation,
the NADH produced by glycolysis is used to reduce the pyruvate produced by glycolysis
to either lactate or ethanol. Fermentation results in a net production of 2 ATP per
glucose molecule.
During strenuous exercise, anaerobic conditions can result if the cardiovascular system
cannot supply oxygen fast enough to meet the demands of muscle cells. Assume that a
muscle cell's demand for ATP under anaerobic conditions remains the same as it was
under aerobic conditions.
What would happen to the cell's rate of glucose utilization? - Answer- Glucose utilization
would increase a lot.
What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate
+ NAD+ - Answer- Pyruvate
Which term describes the degree to which an element attracts electrons? - Answer-
Electronegativity
Which terms describe two atoms when they form a bond in which electrons are
completely transferred from one atom to the other? - Answer- Anion and cation
Which of the following statements is true of the bonds in a water molecule?
A) The electron in each hydrogen atom is completely transferred to the oxygen atom,
and each hydrogen atom has a net charge of +1.
B) Oxygen acts as the electron acceptor and is oxidized.
C) Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
, D) There is equal sharing of the electrons between the oxygen atom and the two
hydrogen atoms, and the net charge is zero. - Answer- C) Oxygen holds electrons more
tightly than hydrogen does, and the net charge is zero.
Which of the following statements is not true of most cellular redox reactions?
A) Changes in potential energy can be released as heat.
B) The electron acceptor is reduced.
C) The reactant that is oxidized loses electrons.
D) A hydrogen atom is transferred to the atom that loses an electron. - Answer- D) A
hydrogen atom is transferred to the atom that loses an electron.
What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?
- Answer- Ionic
Gaseous hydrogen burns in the presence of oxygen to form water:
2H2 + O2 → 2H2 O + energy
Which molecule is oxidized and what kind of bond is formed? - Answer- Hydrogen,
Polar
Which of the following processes is driven by chemiosmosis? - Answer- Oxidative
Phosphorylation
Which of the following metabolic processes normally occurs regardless of whether or
not oxygen (O2) is present? - Answer- Glycolysis
Which molecule is metabolized in a cell to produce energy "currency" in the form of
ATP? - Answer- Glucose
True or false? The potential energy in an ATP molecule is derived mainly from its three
phosphate groups. - Answer- True
Which process is not part of the cellular respiration pathway that produces large
amounts of ATP in a cell? - Answer- Fermentation
Which step of the cellular respiration pathway can take place in the absence of oxygen?
- Answer- Glycolysis
Into which molecule are all the carbon atoms in glucose ultimately incorporated during
cellular respiration? - Answer- Carbon Dioxide
Which of the following statements about the electron transport chain is true? - Answer-
NADH and FADH2 donate their electrons to the chain.
Which stage of glucose metabolism produces the most ATP? - Answer- Electron
transport and chemiosmosis
WITH CORRECT ANSWERS
The rate of cellular respiration is regulated by its major product, ATP, via feedback
inhibition. As the diagram shows, high levels of ATP inhibit phosphofructokinase (PFK),
an early enzyme in glycolysis. As a result, the rate of cellular respiration, and thus ATP
production, decreases. Feedback inhibition enables cells to adjust their rate of cellular
respiration to match their demand for ATP. - Answer- ATP levels would fall at first,
decreasing the inhibition of PFK and increasing the rate of ATP production.
Under anaerobic conditions (a lack of oxygen), glycolysis continues in most cells
despite the fact that oxidative phosphorylation stops, and its production of NAD+ (which
is needed as an input to glycolysis) also stops. The diagram illustrates the process of
fermentation, which is used by many cells in the absence of oxygen. In fermentation,
the NADH produced by glycolysis is used to reduce the pyruvate produced by glycolysis
to either lactate or ethanol. Fermentation results in a net production of 2 ATP per
glucose molecule.
During strenuous exercise, anaerobic conditions can result if the cardiovascular system
cannot supply oxygen fast enough to meet the demands of muscle cells. Assume that a
muscle cell's demand for ATP under anaerobic conditions remains the same as it was
under aerobic conditions.
What would happen to the cell's rate of glucose utilization? - Answer- Glucose utilization
would increase a lot.
What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate
+ NAD+ - Answer- Pyruvate
Which term describes the degree to which an element attracts electrons? - Answer-
Electronegativity
Which terms describe two atoms when they form a bond in which electrons are
completely transferred from one atom to the other? - Answer- Anion and cation
Which of the following statements is true of the bonds in a water molecule?
A) The electron in each hydrogen atom is completely transferred to the oxygen atom,
and each hydrogen atom has a net charge of +1.
B) Oxygen acts as the electron acceptor and is oxidized.
C) Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
, D) There is equal sharing of the electrons between the oxygen atom and the two
hydrogen atoms, and the net charge is zero. - Answer- C) Oxygen holds electrons more
tightly than hydrogen does, and the net charge is zero.
Which of the following statements is not true of most cellular redox reactions?
A) Changes in potential energy can be released as heat.
B) The electron acceptor is reduced.
C) The reactant that is oxidized loses electrons.
D) A hydrogen atom is transferred to the atom that loses an electron. - Answer- D) A
hydrogen atom is transferred to the atom that loses an electron.
What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?
- Answer- Ionic
Gaseous hydrogen burns in the presence of oxygen to form water:
2H2 + O2 → 2H2 O + energy
Which molecule is oxidized and what kind of bond is formed? - Answer- Hydrogen,
Polar
Which of the following processes is driven by chemiosmosis? - Answer- Oxidative
Phosphorylation
Which of the following metabolic processes normally occurs regardless of whether or
not oxygen (O2) is present? - Answer- Glycolysis
Which molecule is metabolized in a cell to produce energy "currency" in the form of
ATP? - Answer- Glucose
True or false? The potential energy in an ATP molecule is derived mainly from its three
phosphate groups. - Answer- True
Which process is not part of the cellular respiration pathway that produces large
amounts of ATP in a cell? - Answer- Fermentation
Which step of the cellular respiration pathway can take place in the absence of oxygen?
- Answer- Glycolysis
Into which molecule are all the carbon atoms in glucose ultimately incorporated during
cellular respiration? - Answer- Carbon Dioxide
Which of the following statements about the electron transport chain is true? - Answer-
NADH and FADH2 donate their electrons to the chain.
Which stage of glucose metabolism produces the most ATP? - Answer- Electron
transport and chemiosmosis
