Download Unit 3: Cellular Energetics

AP Biology
Biology, Campbell and Reece, 10th Edition
Name: ____________________
Adapted from chapter reading guides originally created by Lynn Miriello
Unit 3: Cellular Energetics
Guided Reading Questions (50 pts total)
Chapter 8 – An Introduction to Metabolism
Concept 8.1 – An organism’s metabolism transforms matter and energy, subject to the laws of
thermodynamics.
1. What is a metabolic pathway? Compare and contrast the catabolic and anabolic pathways.
2. Define the following terms. These terms and concepts are critical.
a. energy –
b. kinetic energy –
c. heat/thermal energy –
d. chemical energy –
e. thermodynamics –
f. first law of thermodynamics –
g. second law of thermodynamics –
Concept 8.2 – The free-energy change of a reaction tells us whether or not the reaction occurs
spontaneously.
3. What is “free energy?” Contrast exergonic and endergonic reactions in terms of free energy.
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4. How do you know if a reaction is spontaneous?
5. Can a closed system at equilibrium do work? Why or why not?
Concept 8.3 – ATP powers cellular work by coupling exergonic reactions to endergonic reactions.
6. List and give an example of the three main kinds of cellular work done by ATP.
1.
2.
3.
7. Label the diagram and indicate how cellular work is done by ATP.
8. Define what it means for a molecule to be “phosphorylated.”
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9. In your own words, explain the concept of coupled reactions and explain how this allows ATP to do
“work.”
AP Biology Exam Checkpoint:
_____ 10. Which of the following statements correctly describe(s) some aspect of energy in living organisms?
A. Living organisms can use energy to do work.
B. Organisms expend energy in order to decrease their entropy.
C. Living organisms can convert energy among several different forms.
D. A, B, and C
Chapter 9 – Cellular Respiration: Harvesting Chemical Energy
Concept 9.1 – Catabolic pathways yield energy by oxidizing organic fuels.
1. Define the two catabolic pathways:
a. fermentation –
b. aerobic respiration 2. Use the following terms correctly in a sentence: redox reactions, oxidation, reduction, reducing agent
and oxidizing agent.
3. Why does being “reduced” correspond to having greater potential energy?
4. In cellular respiration, what is being oxidized and what is being reduced?
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5. Label the diagram below of the electron movement with regard to the coenzyme NAD+ (Figure 9.4).
6. Why are electron transport chains an advantage to living systems?
7. What are the three stages of aerobic cellular respiration?
1.
2.
3.
8. What is substrate-level phosphorylation? Label the diagram to support your answer (Figure 9.7).
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Concept 9.2 – Glycolysis harvests chemical energy by oxidizing glucose to pyruvate.
9. Complete the chart of glycolysis shown here (Similar to Figure 9.8):
Concept 9.3 – After pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation of
organic molecules.
10. Take a deep breath and exhale. Identify the processes in your body that produced the CO 2 that you just
exhaled.
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11. Study the detailed diagram of the citric acid cycle (Figure 9.12) and answer the questions below.
a. Where does the C “go” that is removed?
b. What is happening when NAD+ -> NADH + H+?
c. Where is substrate level phosphorylation happening?
Concept 9.4 – During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis.
12. What is oxidative phosphorylation?
13. Define chemiosmosis and label the diagram on the right (Figure 9.14). Answer the question that follows.
Definition:
Question: How does chemiosmosis relate to osmosis involving water?
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14. Label the diagram of the activities occurring on the ETC and answer the question below the diagram
(Figure 9.15).
Question: What are cytochromes and what is their role in this process?
15. Study the summary diagram of cellular respiration (Figure 9.16). You are expected to know these
numbers and locations! Explain exactly how the total of 26 or 28 ATP (see the yellow bar in the figure)
was calculated.
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Concept 9.5 – Fermentation and anaerobic respiration enable cells to produce ATP without the use of
oxygen.
16. Label the diagrams of fermentation and answer the question below (Figure 9.17).
Question: What is the overall purpose of fermentation? In other words, why does fermentation occur?
17. What is the evolutionary significance of glycolysis?
Concept 9.6 – Glycolysis and the citric acid cycle connect to many other metabolic pathways.
18. Under what circumstances might your body synthesize fat molecules?
19. Why would AMP stimulate cellular respiration and ATP inhibit it?
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AP Biology Exam Checkpoint:
Frogs of three different species were weighed and the
amount of oxygen consumed by each species was determined
by placing them in a respirometer for 1 hour. The results of
this experiment are shown on the right.
Species
1
2
3
Average Mass
(grams)
15
11
21
cm3 of O 2
consumed per hour
0.75
0.55
1.05
_____ 20. From the information in the table, it is most reasonable to conclude that
A. each species of frog has its own unique rate of respiration.
B. the amount of oxygen consumed per gram of body weight for each species is the same.
C. the amount of oxygen consumed per gram of body weight by the largest frog is almost three
times that by the smaller frog.
D. since all frogs respire through their skin, smaller frogs with smaller surface areas will consume
less oxygen per gram of body weight than larger frogs with larger surface areas.
Chapter 10 – Photosynthesis
Concept 10.1 – Photosynthesis converts light energy to the chemical energy of food.
1. Label the diagram on the right (Figure 10.4) and answer the question below.
Question: How do the reactant molecules need for photosynthesis get from the outer environment to the
chloroplasts in leaves?
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2. Use the diagram below to label and identify the two broad stages of photosynthesis (Figure 10.6).
3. What is carbon fixation? Where does it typically occur in a plant cell?
Concept 10.2 – The light reactions convert solar energy to the chemical energy of ATP and NADPH.
4. What is a photon?
5. Why are leaves green?
6. Study Figure 10.10. What is the difference between an absorption spectrum and an action spectrum?
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7. What happens to chlorophyll when it is hit by light? How does this relate to potential energy?
8. Identify the following parts of a photosystem:
a. photosystem –
b. light harvesting complex –
c. reaction center complex d. primary electron acceptor 9. What are the steps in linear (noncyclic) electron flow in photosynthesis? (Figure 10.14)
10. What is cyclic electron flow? (Figure 10.16)
11. Compare and contrast chemiosmosis in
mitochondria and chloroplasts - label the
diagram to assist – but also write a response
below (Figure 10.17).
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12. Use the diagram below to summarize the activities in the light reactions of photosynthesis (Figure 10.18).
Concept 10.3 – The Calvin cycle uses the chemical energy of ATP and NADPH to reduce CO 2 to sugar.
13. Describe and explain the overall purpose of the Calvin cycle and each phase listed below:
a. Calvin cycle –
b. carbon fixation -
c. reduction –
d. regeneration -
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14. Label the diagram below of the Calvin Cycle (Figure 10.19).
Concept 10.4 – Alternative mechanisms of carbon fixation have evolved in hot, arid climates.
15. What is a plant’s most valuable resource and what environmental factors caused plants to evolve
adaptations for hot, arid climates?
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16. Explain why photorespiration is considered such a “waste.”
17. Label the diagram below to explain the anatomy of C 4 plants (Figure 10.20).
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18. Draw a diagram similar to Figure 10.21 to compare the C 4 and CAM pathways.
C4
CAM
19. Label the diagram below to summarize the activities of photosynthesis.
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AP Biology Exam Checkpoint:
The graph to the right shows the relationship of
photosynthetic rate and irradiance (light intensity) as it
is influenced by both temperature and carbon dioxide
level.
_____ 20. According to the graph, the greatest rate of
photosynthesis occurs when CO 2 is present at
A.
B.
C.
D.
low concentrations
high concentrations
high concentrations and low irradiance levels
high concentrations and high irradiance levels
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