AP BIOLOGY Test Booklet
cellular respiration
Pyruvate dehydrogenase is an enzyme that converts pyruvate to acetyl- . Acetyl- is further metabolized in the
Krebs cycle. A researcher measured the accumulation of acetyl- in a reaction containing pyruvate and pyruvate
dehydrogenase under several different conditions (Figure 1).
Figure 1. Accumulation of acetyl- under different conditions
1. Which of the following best describes the cellular location where pyruvate dehydrogenase is most likely active?
(A) The cytosol
(B) The lysosomes
(C) The nucleus
(D) The mitochondrial matrix
Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each
phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than
once, or not at all.
This group of questions refers to molecules of the following substances.
(A) Cytochrome
(B) FADH2
(C) NAD+
(D) NADP+
(E) Oxygen (O2)
2. An intermediate electron acceptor for oxidations that occur in both glycolysis and in Krebs cycle reactions
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cellular respiration
(A) Cytochrome
(B) FADH2
(C) NAD+
(D) NADP+
(E) Oxygen (O2)
3. ATP serves as a common energy source for organisms because
(A) it is the smallest energy molecule
(B) it stores the least energy of any energy source
(C) its energy can be easily transferred to do cellular work
(D) it is extremely stable and can be stored in the cell for long periods of time
(E) traces of it have been found in fossils of ancient organisms dating back to the beginning of life on Earth
4. During respiration, most ATP is formed as a direct result of the net movement of
(A) potassium against a concentration gradient
(B) protons down a concentration gradient
(C) electrons against a concentration gradient
(D) electrons through a channel
(E) sodium ions into the cell
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Test Booklet
cellular respiration
To investigate bacterial metabolism, a researcher divided a population (culture) of Staphylococcus capitis bacteria into
two sets of culture tubes containing glucose. The researcher added a chemical to one set of tubes and measured the of
the cultures at -minute intervals as the bacteria metabolized the glucose into lactic acid. The data are shown in Table 1.
TABLE 1. AVERAGE CHANGE IN IN CONTROL AND TREATMENT GROUPS OVER A -MINUTE
PERIOD
Average of Control Average of Treatment
Time (min)
( ) ( )
5. Which of the following best describes the process by which the bacteria are breaking down the glucose to produce
lactic acid?
(A) The bacteria are breaking down sugars in the absence of oxygen.
(B) The bacteria are creating a gradient to synthesize more .
(C) The bacteria are using their mitochondria to break down glucose in the presence of oxygen.
(D) The bacteria are producing in the Krebs cycle that is then converted into lactic acid.
6. Which of the following statements about mitochondrial chemiosmosis is NOT true?
(A) A proton gradient is established across the inner membrane of the mitochondrion.
(B) The potential energy released from the mitochondrial proton gradient is used to produce ATP.
(C) The mitochondrial proton gradient provides energy for muscle contraction.
(D) Proteins embedded in the inner mitochondrial membrane play an important role in ATP synthesis.
(E) Heat energy is required to establish the electron transport chain.
7. According to the chemiosmotic theory (chemiosmotic coupling), the energy required to move protons from the
mitochondrial matrix to the intermembrane space against a concentration gradient comes most directly from
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cellular respiration
(A) photons of red or blue light
(B) the hydrolysis of ATP
the breakdown of high-energy fatty acids in
(C)
the mitochondrial matrix
electrons flowing along the electron transport
(D)
chain
(E) substrate-level phosphorylation
8.
Figure 1. The electron transport chain of cellular respiration. The bold arrows passing through the complexes in the
membrane represent the path of electron flow in mitochondria.
Compound binds to complex of the mitochondrial electron transport chain and prevents complex from
accepting electrons.
Based on Figure 1, which of the following best explains why the cells of an animal exposed to compound have an
increased ratio of to ?
increases because compound directly prevents synthase from producing the
(A)
necessary for the oxidation of to .
increases because the binding of compound to complex also prevents the transport of
(B)
out of the mitochondria.
cannot be oxidized to because complexes , , and cannot accept electrons if electrons
(C)
cannot be passed to complex .
cannot be oxidized to because cannot bind to the active site of complex if this
(D)
complex cannot accept electrons.
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cellular respiration
9.
Which of the following questions will best direct an investigation of the mechanism of ATP synthase?
(A) What is the source of the inorganic phosphate that is used to generate ATP from ADP?
(B) Is the phosphorylation of ADP by ATP synthase dependent on the formation of a proton gradient?
Can ATP synthase use the energy released by phosphorylation of ADP to pump protons against a
(C)
concentration gradient?
(D) Can oxidative phosphorylation be uncoupled from the electron transport chain?
10. Which of the following describes a metabolic consequence of a shortage of oxygen in muscle cells?
(A) An increase in blood pH due to the accumulation of lactic acid
(B) No ATP production due to the absence of substrate-level phosphorylation
(C) A buildup of lactic acid in the muscle tissue due to fermentation
(D) A decrease in the oxidation of fatty acids due to a shortage of ATP
11.
The figure above shows an organelle typically found in eukaryotic cells. Which of the following best describes the
function of the double membrane system of this organelle?
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cellular respiration
The outer membrane allows the transport of all molecules into the intermembrane space, while the inner
(A)
membrane serves as the regulatory boundary.
The inner membrane has specialized proteins that create a hydrogen ion concentration gradient between the
(B)
intermembrane space and the matrix.
The outer membrane contains transport proteins that establish a sodium ion concentration gradient used for
(C) ATP production, while the inner membrane contains transport proteins that establish a hydrogen ion
concentration gradient used for glucose production.
The toxins and wastes entering a cell cross the outer membrane and are detoxified by digestive enzymes
(D)
stored within the intermembrane space.
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