Unit Three: Cell Energy Processes
Part 1: Capturing Solar Energy: Photosynthesis, Chapter 7
Part 2: Harvesting Energy: Glycolysis & Cellular Respiration, Chapter 8
Big Idea 2: Biological systems utilize free energy and molecular building blocks to grow, to
reproduce, and to maintain dynamic homeostasis.
Enduring understanding 2.A: Growth, reproduction and maintenance of
the organization of living systems require free energy and matter
“…the cells of life bound themselves into clans, a multitude of cells
To make one being – as the molecules before
Had made of many one cell. Meanwhile they had invented
Chlorophyll and ate sunlight, cradled in peace
On the warm waves.”
- Robinson Jeffers in The Beginning and the End (1963)
Learning Objectives:
o LO 2.1 The student is able to explain how biological systems use free energy based on empirical data that all
organisms require constant energy input to maintain organization, to grow and to reproduce.
o LO 2.2 The student is able to justify a scientific claim that free energy is required for living systems to maintain
organization, to grow or to reproduce, but that multiple strategies exist in different living systems.
o LO 2.3 The student is able to predict how changes in free energy availability affect organisms, populations and
ecosystems.
o LO 2.4 The student is able to use representations to pose scientific questions about what mechanisms and
structural features allow organisms to capture, store and use free energy.
o LO 2.5 The student is able to construct explanations of the mechanisms and structural features of cells that allow
organisms to capture, store or use free energy.
o LO 2.6 The student is able to use calculated surface area-to-volume ratios to predict which cell(s) might eliminate
wastes or procure nutrients faster by diffusion.
o LO 2.7 Students will be able to explain how cell size and shape affect the overall rate of nutrient intake and the
rate of waste elimination.
o LO 2.8 The student is able to justify the selection of data regarding the types of molecules that an animal, plant or
bacterium will take up as necessary building blocks and excrete as waste products.
o LO 2.9 The student is able to represent graphically or model quantitatively the exchange of molecules between an
organism and its environment, and the subsequent use of these molecules to build new molecules that facilitate
dynamic homeostasis, growth and reproduction.
Reading Assignment:
all Ch. 7
AP Investigations:
Investigation #5: Photosynthesis
Advanced Placement Biology
Mr. DePhillips
Review…look over info from the Chemistry unit…
Essential knowledge 2.A.1: All living systems require constant input of free energy.
Essential knowledge 2.A.2: Organisms capture and store free energy for use in biological processes.
6-1: What is Energy? (p. 102)
1. Define energy.
2. (You can ignore kinetic/potential and the 1st Law of Thermodynamics for this course.)
3. Do living things violate the 2nd Law of Thermodynamics? Define entropy. How can entropy be overcome?
4. All life on Earth is dependent on the energy producing capabilities of __________. Explain how this overcomes the concept
of entropy.
6-2: How Does Chemical Energy Flow in Chemical Reactions? (p. 103)
5. Give details to tell the difference between exergonic and endergonic reactions. Use the pictures and examples to help you.
6. Most chemical reactions need activation energy. What is this energy? Give a few examples. Does our body have enough
energy to run all these chemical reactions all by itself? Explain!
7. Describe the concept of a coupled reaction.
6.3: How is Cellular Energy Carried Between Coupled Reactions? (p. 105)
1. Our Energy Currency: ATP. What does ATP stand for? What are its monomers? Where is the energy stored?
2. How is ATP formed from ADP? Where does the energy come from?
3. Now we meet a few important molecules… NAD+ and FAD. Why are the important? What is their role in the functioning of
your body? (Know them now…they become important a few inches down!)
(Words to know: autotroph, heterotroph, chemosynthesis, photosynthesis, hydrolysis, fermentation.)
Chapter 7: Capturing Solar Energy: Photosynthesis
1. Write the definition of photosynthesis and MEMORIZE the equation.
2. What allows CO2 to enter the cell? Describe their characteristics.
3. Describe the structural make-up of a chloroplast. Include stroma, thylakoid, and grana in your answer.
4. What is the difference between the light and dark reaction of photosynthesis? (Light and dark, are, of
course, the easy way of writing light-dependent and light-independent.) Where does each process take
place?
5. Summarize the light reaction. What are the reactants, and what are the products?
6. What ‘part’ of sunlight is used for photosynthesis? What does it do? What color of light is used by
plants? What are the wavelengths used?
7. Describe the set-up of a general photosystem. How does it harvest light? What is its electron transport
system do?
8. The Light Reactions take place in 2 photosystems…first Photosystem II followed by Photosystem I. (Yep,
you read that right.) Figure 7.7 is a graph showing the movements of electrons (energy level of the
electrons is on the Y-axis over time on the X-axis.) Figure 7-8 is the actual photosystems and electron
transport chains in the thylakoid membrane. Use both to understand the Light reactions.
9. Where does photosystem II get its supply of electrons? Describe the reaction and what is released.
10. Box on p. 124 = chemiosmosis. Know how the enzyme ATP synthase works. This process is NOT limited
to the Light Reactions. You will see this again at the end of cellular respiration.
11. Read the summing up on page 125 for a good summary of things you should know.
12. What 4 things does the Calvin-Benson cycle (a.k.a.: Calvin Cycle, C3 cycle, dark reactions, lightindependent reactions) require?
13. What is carbon fixation? What gives the C3 cycle its name?
14. After carbon fixation, what are the next two steps of the dark reaction?
15. Sum up the Dark reactions. What are the products…the reactants…what’s going to happen next?
16. What molecules are transferred from the light reactions to the dark reactions? Where are these
molecules stored?
17. Read section 4. Be sure to review the information they direct your attention to. Where do the reactions
take place?
✘Memorization of the steps in the Calvin cycle, the structure of the molecules, and the names of enzymes (with
the exception of ATP synthase) are beyond the scope of the course and the AP Exam. ✘