AP Biology

The Plant Unit

Reading Guide – Chapter 6.5–6.6

Chapter 6.5–6.6 – Photosynthesis*

*Adapted and modified from Robbyn Tuinstra’s work

  1. In general, describe what happens during photosynthesis and write a summary equation.
  1. What are the reactants in photosynthesis?
  1. What are the products of photosynthesis?
  1. Where in the cell does photosynthesis occur?
  1. What substance is oxidized?
  1. What substance is reduced?
  1. What is the source of O2 produced in photosynthesis?
  1. Photosynthesis is described as an endergonic redox process.
  1. Explain why it is an endegonic process.
  1. What substance is oxidized?To what is it oxidized?
  1. What substance is reduced?To what is it reduced?
  1. Identify the two stages of photosynthesis and briefly describe what happens during each stage in the chart below.

Stage / Events
  1. What is the difference between an absorption spectrum and an action spectrum?

Absorption Spectrum / Action Spectrum
  1. What pigments are involved (directly and indirectly) in photosynthesis?
  2. In general, describe the structure of a photosystem.
  1. Compare and contrastphotosystems I and II in photosynthesis.

Photosystem I / Photosystem II
  1. Compare and contrast cyclic and noncyclic electron flow (Figures 6.19 and 6.20, respectively) in the chart below.

Cyclic Electron Flow / Noncyclic Electron Flow
  1. What is the role of water in noncyclic electron flow?
  1. Why does a plant use both cyclic and noncyclic pathways?

Light Reactions – Cyclic Electron Flow

Light Reactions – NonCyclic Electron Flow

  1. Describe the organization of the thylakoid membrane, the location of the various components of the light reactions, and how ATP is produced by chemiosmosis. You may find it helpful to sketch a diagram similar to Figure 10.12, indicating where H+ become concentrated and ATP is produced.
  1. Summarize the light reactions below.

Reactants / Products
  1. Summarize the three stages of the Calvin Cycle below.

Stage / Summary (Reactants and Products)
  1. Fill in the following diagram by correctly identifying the molecules.

  1. What isrubisco? What is its role in the Calvin cycle?
  1. Where does the Calvin Cycle occur within the chloroplasts?
  1. For each glyceraldehydes-3-phosphate molecule that exits the Calvin cycle:

______molecules of CO2 enter the cycle

______molecules of ATP are used

______molecules of NADPH are used

______turns of the Calvin cycle are required

  1. What are the possible fates of G3P?
  1. For each glucose molecule produced by photosynthesis:

______molecules of CO2 are used

______molecules of ATP are used

______molecules of NADPH are used

______turns of the Calvin cycle are required

  1. Summarize the Calvin cycle below:

Reactants / Products

______

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