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1. Catabolism is the ________.
a. breaking down of molecules for energy
b. building up of large molecules from smaller ones
c. sum total of all chemical reactions involved in maintaining the living cell
d. series of consecutive biochemical reactions
e. generation of cations by oxidation reactions
2. Which of the following statements about mitochondria is(are) correct?
Mitochondria contain a multi-folded outer membrane and an unfolded inner
a. membrane.
The space between the inner and outer mitochondrial membrane is called the
b. matrix.
The inner mitochondrial membrane separates the matrix from the ATP-
c. synthase.
d. The ATP-synthase is located within the mitochondrial inner membrane.
e. All of these are correct.
3. In the common metabolic pathway, which of the following molecules act(s) as a carrier of
hydrogen ions and electrons?
1. ATP
2. NAD+
3. Coenzyme A
4. FAD
a. 1 only
b. 2 only
c. 3 only
d. 2 and 4
e. 2, 3, and 4
4. The following molecule is NAD+. Which part of the molecule, indicated by numbers,
actively participates in redox reactions by accepting H+ ions and electrons?
a. 1
b. 2
c. 3
d. 4
e. 5
5. The following molecule, ATP, contains a high-energy bond. Which bond(s), indicated by
number, is(are) the high-energy bond(s)?
a. 1 only
b. 2 only
c. 3 only
d. 1 and 2
e. 1, 2, and 3
6. Why is ATP a high-energy molecule?
a. Phosphate groups contain a high energy P=O double bond.
b. Phosphate-ribose bonds are highly reactive.
c. Adenine bases contain resonance bonds between many C and N atoms.
Three phosphate groups, containing four negative charges, produce high bond
d. strain.
e. Phosphate and adenine can form multiple hydrogen bonds with each other.
7. The designation, Pi, represents which of the following species (at pH 7.4)?
a.
b.
c.
d.
e.
8. The common metabolic pathway is used to generate the majority of human ATP. Which of
the following metabolic pathways is(are) considered to be part of the common metabolic
pathway?
1. citric acid cycle
2. electron transport chain
3. oxidative phosphorylation
a. 1 only
b. 2 only
c. 3 only
d. 2 and 3
e. 1, 2, and 3
9. The reactions involved in the citric acid cycle occur in the:
a. cytoplasm of the cell.
b. mitochondrial inner membrane.
c. mitochondrial matrix.
d. mitochondrial intermembrane space.
e. cell nucleus.
10. What eventually happens to the carbon atoms of acetyl CoA after they enter the citric acid
cycle?
a. They are removed from carboxylic acids as waste CO2.
b. They become part of ATP.
c. They are passed on to NAD+ and FAD.
d. They are used to synthesize glucose.
e. They combine with the oxygen we breathe to make CO2.
11. In the middle of the citric acid cycle, succinate is converted to fumarate (reaction shown
below). This reaction requires FAD which is converted to FADH2. In this reaction:
a. FAD is reduced and succinate is oxidized.
b. FAD is oxidized and succinate is reduced.
c. both FAD and succinate are oxidized.
d. both FAD and succinate are reduced.
e. which is an acid-base reaction, FAD and succinate are neutralized.
12. In the citric acid cycle fumarate is converted to malate (reaction shown below). Examine
the changes which occur in the functional groups of these two molecules. This reaction can
be classified as what type of chemical reaction?
a. oxidation of a primary alcohol
b. oxidation of a secondary alcohol
c. oxidation of a tertiary alcohol
d. dehydration of an alcohol
e. dehydrogenation of a ketone
13 In step number 8 of the citric acid cycle malate is converted to oxaloacetate?
.
This reaction can be classified as a(n) ________.
a. oxidation of a primary alcohol
b. oxidation of a secondary alcohol
c. oxidation of a tertiary alcohol
d. dehydration of an alcohol
e. dehydrogenation of a ketone
14. The citric acid cycle is regulated by ATP which binds to the first enzyme of the pathway
and inhibits the formation of citric acid from acetyl CoA and oxaloacetate. This form of
regulation can be classified as ________.
a. competitive inhibition
b. positive allosterism
c. irreversible inhibition
d. feedback inhibition
e. oxidative inhibition
15. How many electrons are carried along the electron transport chain each time a NADH
molecule transfers its electrons to the first fixed enzyme complex in the electron transport
chain?
a. 1
b. 2
c. 3
d. 4
e. 5
16. Which of the following transition metals is used to pass electrons down the electron
transport chain in the oxidative phosphorylation pathway?
a. Ca
b. Mg
c. Mn
d. Fe
e. Cu
17. What waste product is produced by the electron transport chain and oxidative
phosphorylation pathways?
a. O2
b. H20
c. CO2
d. NAD+
e. H+
18. Within the inner membrane of the mitochondria, the flow of electrons along the electron
transport chain is used to:
a. attach a phosphate group directly to an ATP molecule.
b. power a proton pump.
c. convert NADH to FAD.
d. regenerate CoA for another trip around the citric acid cycle.
e. oxidize molecular oxygen to produce water.
19. At the end of the electron transport chain of oxidative phosphorylation, oxygen combines
with H+ and electrons to form H2O. The oxygen comes from:
a. decarboxylation of citric acid.
b. hydrolysis of water by the electron transport chain.
c. the air we breathe.
d. acetyl-CoA.
e. CO2 generated by the citric acid cycle.
20. If oxygen were not available to the cell, the operation of the citric acid cycle would
________.
stop because oxygen is required as a substrate for the oxidation reactions in the
a. citric acid cycle
be unaffected because oxygen ion, O-, not molecular oxygen, O2 , is required
b. for the oxidation reactions in the citric acid cycle
stop because oxygen is required as a cofactor for the operation of some of the
c. citric acid cycle enzymes
d. be unaffected because only the electron transport chain requires oxygen
stop because NADH and FADH2 are not recycled to NAD+ and FAD when
e. the electron transport chain stops
21. As electrons pass down the electron transport chain, their energy ________.
a. becomes heat
b. is used to pump H+ ions into the intermembrane space
c. is used to make inorganic phosphate ions
d. is used to pump water into the mitochondrial matrix
e. is used by CoQ to attach two phosphate ions to AMP to make ATP
22. Why does FADH2 produce one less ATP molecule than does NADH?
a. FADH2 is a smaller molecule and has less energy.
FADH2 transfers its electrons to CoQ in the middle of the electron transport
b. chain.
FADH2 has electrons spread out on two H+ ions, rather than one H+ ion like
c. NADH does.
FADH2 requires a shuttle system to reach the ETC and uses one ATP
d. molecule in the process.
e. FADH2 is too large to enter the intermembrane space.
23. ATP synthesis by way of the oxidative phosphorylation pathway depends on the passage of
which of the following substances through membrane-bound ATP synthase?
a. NADH
b. FADH2
c. H+
d. NAD+
e. CoA
24. Cyanide is one of the fastest-acting poisons known. It binds to cytochrome a3 at the end of
the electron transport chain (ETC) and blocks the transfer of electrons to oxygen. What
specifically causes cell death?
Without electron flow through the ETC, proton pumps stop and ATP
a. generation stops.
b.
The citric acid cycle stops because electrons can't be transferred to NAD+ from
FAD.
c. Glycolysis stops because NAD+ can't be recycled by the ETC.
d. Water can't form at the end of the ETC and death results from dehydration.
The citric acid cycle stops because the excess electrons combine to neutralize
e. the charge on NAD+.
25. There are many biological molecules that contain high-energy phosphate bonds. ATP is
used to power life processes because the energy of hydrolysis of ATP is ________.
a. intermediate between the energies of hydrolysis of other organophosphate molecules
b. small enough that ADP can easily be recycled back to ATP
c. large enough to power biologically useful reactions
d. All of these.