Biology 12

94 MHR • Unit 1 Metabolic Processes

SECTION REVIEW

1. Draw a chloroplast and label the key structures.


2. Explain how plants capture solar energy.
   Why does photosystem 680 provide some adaptive
   advantages over photosystem 700?


3. Write an equation to summarize the photo
   reaction of photosynthesis.


4. What are the components of a photosynthetic
   unit, and what roles do they play? In which part of
   the chloroplast are photosynthetic units located?


5. What role does water play in the photo
   reactions of photosynthesis?


6. List the three stages of the Calvin cycle.
   For each stage, identify the energy input and
   the product(s).


7. What becomes of the atmospheric carbon
   fixed by a plant cell?


8. Explain, with diagrams, how high levels of oxygen
   reduce the effectiveness of the Calvin cycle. Explain
   how alternative forms of carbon fixation avoid this
   problem.
   9. How many CO 2 molecules need to be fixed to
   produce 2 PGAL molecules that can leave the Calvin
   cycle to form glucose?


9. In an experiment, a team of researchers uses a
   heavy isotope of oxygen-18 to track the passage of
   oxygen through the process of photosynthesis. What
   results would you expect to find if the researchers
   initiated the reaction in an environment in which
   (a)the carbon dioxide contained the heavy oxygen?
   (b)the water contained the heavy oxygen?


10. You are hired to advise strawberry producers on
    ways to increase their harvest. Assume the plants are
    grown under fully controlled conditions, so you can
    alter the temperature, lighting, atmosphere, water
    supply, and nutrients.
    (a)What conditions would you recommend to
    maximize the plants’ productivity?
    (b)Can you think of any mutation that would help
    increase the rate or efficiency of photosynthesis?
    Discuss your reasoning.

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