Chapter 8 Study Guide

14) Be able to explain the mechanisms of C4 and CAM photosynthesis and how these evolutionary adaptations are related to photorespiration.

- C4 photosynthesis seperates initial fixation from rubisco activity spatially and takes extra energy. Higher tendency for photorespiration - CAM Photosynthesis seperates initial fixation from rubisco activity temporarily and CO2 is stored at night and used during the day when stomates open and used in calvin cycle. minimizes photorespiration

6) Be able to explain where each phase of photosynthesis occurs within a cell.

- Light Dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis the Calvin cycle. Occurs in the thykaloid membranes of organelles called chloroplasts - the Calvin cycle is the set of chemical reactions that take place in chloroplasts and uses products of light-dependent reactions

2) Be able to explain the roles of photosynthesis in the ecosystem based on its substrates and products.

- Photosynthesis is the source of all chemical energy in the ecosystem. Allows plants to make energy and food. Creates food for animals. Plants would not be able to grow or produce without it

13) Be able to explain photorespiration, including the environmental conditions under which it occurs.

-Photorespiration is a respiratory process in many higher plants by which they take up oxygen in the light and give out some carbon dioxide - Occurs when the calvin cycle enzyme rubisco acts on oxygen rather than CO2

7) Describe the pathway of electron transport in non-cyclic electron transport and the role of each photosystem.

-the non-cyclic pathway produces ATP and NADPH. Electrons are removed from water and passed through Photosystem 2 and photosystem 1 before ending up in NADPH. Requires light to be absorbed twice - Photosystem 1 makes NADPH and does not take place first Photosystem 2 makes ATP and uses electrons from light

10) Be able to describe what is happening in all three phases of the Calvin cycle. Know which require energy

1) Carbon fixation - method plants use to attach carbon dioxide from the atmosphere to a chemical (RuBP) in order to start the process of photosynthesis. 2) Reduction phase - second step in the Calvin cycle of photosynthesis, where energy reacts with chemicals to create the simple sugar G3P. 3) Regeneration - A series of chemical reactions uses energy from ATP to rearrange the atoms of the 5 G3P molecules, (15 total carbons), which forms 3 RuBP molecules (15 total carbons). These will start another turn of the cycle.

11) In what form does fixed carbon leave the Calvin Cycle and what is it used for?

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12) Be able to predict the effects of disturbing the photosynthetic process at multiple points.

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8) How and why is oxygen produced in photosynthesis?

By using sunlight, plants convert CO2 and water into carbohydrates and oxygen and oxygen is needed to breakdown sugar into CO2

5) Describe the molecules which absorb light for photosynthesis. What effect does light absorption have on these molecule? Describe their location in the cell and distribution relative to other components of the light-dependent reactions.

CO2 and water molecules

9) How is ATP synthesized in the light-dependent reactions?

Light is absorbed and the energy is used to drive electrons from water to generate NADPH and to drive protons across a membrane. These protons return through ATP synthase to make ATP.

3) What is the relationship between the light capture reactions and the Calvin Cycle in terms of timing (when they occur)?

Photosynthesis depends on an interaction between two sets of reactions: the light reactions and the Calvin cycle. Chlorophyll and the other molecules responsible for the light reactions are built into the thylakoid membranes. The enzymes that catalyze the Calvin cycle are located in the stroma. The light reactions convert light energy into chemical energy in the form of ATP and NADPH. The ATP provides the energy, and the NADPH supplies the electrons for the Calvin cycle, which converts carbon dioxide to sugar. The ADP and NADP+ that result from the Calvin cycle shuttle back to the light reactions, which regenerate ATP and NADPH.

4) What are the substrates and products of each phase of photosynthesis?

The first stage of photosynthesis is the light reactions stage. The reactant used in this stage is water, and the product is oxygen. The second stage is the Calvin cycle and the reactant used is carbon dioxide, and the product is glucose.

1) Know the substrates and products of photosynthesis. Be able to explain how the products of photosynthesis are related to the substrates of cellular respiration.

photosynthesis produces glucose and oxygen. Photosynthesis makes the glucose that is used for cellular respiration to make ATP. The glucose is then turned back into CO2 which is used in photosynthesis