AP Biology Unit 3: Cellular Energetics
Explore AP Biology Unit 3 questions on enzyme function, environmental effects, cellular energy, photosynthesis, and cellular respiration.
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- AP Biology
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3 Cellular Energetics question 1
Figure 1 shows the reactions of the metabolic pathway used to synthesize amino acid B from
amino acid A in cells.
Figure 1. Synthesis of amino acid B from amino acid A
Question (a)
(a)
Describe a characteristic of an enzyme's active site that allows it to catalyze a specific
chemical reaction.
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Question (b)
(b)
Based on Figure 1, explain how the binding of amino acid A to enzyme 1 is regulated by
amino acid B.
[ 1 ]
Question (c)
(c)
Using the information in Figure 1, identify the product of the reaction catalyzed by enzyme
2: intermediate X, intermediate Y, or amino acid B.
[ 1 ]
Question (d)
(d)
Based on Figure 1, explain how a change in pH could affect enzyme 3 in such a way that
amino acid B cannot be produced.
[ 1 ]
3 Cellular Energetics question 2
Questions 34-38 A student is investigating photosynthesis in plants. The student planted grass seeds in a tray with three sections and grew the grass under artificial lights for 14 days (Figure 1). After 14 days, the student collected all of the grass from section I and recorded its mass (Table 1). The student then placed a clear cover over section II and placed an aluminum foil cover over section III (Figure 2). The student then placed the tray back under the artificial lights for seven additional days. On day 21, the student collected and measured the mass of the grass from sections II and III (Table 1).
Figure 1. A tray of grass seed, grown under light for 14 days
Figure 2. Modifications made to sections II and III on day 14
TABLE 1. MASS OF GRASS GROWN IN EACH SECTION
Which of the following best explains the connection between energy, growth, and the maintenance of an ordered system in the experiment?
A
Energy input from light is required for the grass to grow and maintain an ordered structure.
B
The grass obtains the energy for growth and maintenance of order from nutrients from the soil.
C
The grass couples the release of energy from the light reactions with the production of oxygen used to produce sugars for growth.
D
Energy is required for the growth of the grass but not the maintenance of order.
3 Cellular Energetics question 3
A cross section of a chloroplast showing membranes and the spaces between membranes is shown in Figure 1.
Figure 1. A diagram of the cross section of a chloroplast
Question (a)
(a)
Describe the major process that takes place in this eukaryotic organelle.
[ 1 ]
Question (b)
(b)
Explain the function of the structure labeled with an X in Figure 1.
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Question (c)
(c)
On the template in the space provided for your response, represent the location where carbon fixation takes place by writing " CF " and the location of the electron transport proteins by writing " ETP ".
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Question (d)
(d)
Explain how the shape and stacking of the thylakoids contributes to the rate of carbon fixation by the chloroplast.
TO BEGIN YOUR ANSWER TO QUESTION 5.
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