Chapter 4 Where Does Come From The Calvin Cycle

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Chapter 4

Metabolism in Cells

CHAPTER OUTLINE

Metabolism

Oxidation-reduction reactions occur in metabolism

Electrons associated with hydrogen are transferred to electron acceptor molecules

Photosynthesis

Light exhibits properties of both waves and particles

The carbon fixation reactions produce carbohydrates

Photosystems I and II are light–harvesting units of the light–dependent reactions

ATP synthesis occurs by chemiosmosis

Most plants use the Calvin cycle to fix carbon

Photorespiration reduces the efficiency of the C3 pathway

Many plants with tropical origins fix carbon using the C4 pathway

Many desert plants fix carbon using the CAM pathway

Aerobic or anaerobic pathways

Aerobic respiration

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CHAPTER OBJECTIVES

1. Relate the transfer of electrons (or hydrogen atoms) to the transfer of energy.

2. Define photosynthesis and describe how photosynthesis is important not only to

plants, but to the entire web of life on planet Earth.

LECTURE OUTLINE

I. Introduction to metabolism

A. What are biochemical pathways?

B. Define anabolic and catabolic reactions.

II. Electron transfers: Oxidation-reduction reactions and electron carriers

A. What is oxidation? Reduction?

E. What is the function of electron acceptor molecules?

III. What does photosynthesis mean?

A. What kinds of organisms photosynthesize?

B. Give the general chemical formula for photosynthesis.

C. Light energy: The electromagnetic spectrum

1. What is a photon? How does light exhibit properties of both particles and

waves?

3. What is the stroma?

4. What is a pigment?

a. What kinds of pigments are generally found in chloroplasts of

plants?

E. Summarize the energy-capturing reactions of photosynthesis, also called the light-

dependent reactions.

1. What is the overall goal of this set of reactions?

2. What are the products of the light-dependent reactions?

3. What will be the fate of these products?

4. What is a photosystem? What are the molecular components of

photosystems? Where are they located?

8. What links photosystem I with photosystem II?

9. What is the difference between “noncyclic” and “cyclic” electron

transport?

10. How does the chemiosmotic model explain ATP synthesis?

F. The Calvin cycle (carbon fixation), also called the light-independent reactions

1. What is the overall goal of this set of reactions?

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G. What is the C4 carbon-fixing pathway and why is it called C4 (the Calvin cycle is

C3)?

1. Where do the C3 and C4 pathways get their names?

2. What is photorespiration and how does it reduce photosynthetic efficiency?

IV. What is cellular respiration?

A. What is the overall goal of cellular respiration?

B. What are the types of cellular respiration?

V. What is aerobic respiration?

A. Overview

1. What are the four stages of aerobic respiration?

2. What is the summary equation for aerobic respiration?

B. Where in the cell does glycolysis take place?

1. What are the two phases of glycolysis?

C. Describe the reactions for the formation of acetyl coenzyme A that take place

between glycolysis and the Krebs cycle.

1. Where do the transition reactions occur?

2. What are the beginning and end products of the transition reactions?

3. What waste molecule is produced? How many per pyruvate? Per glucose?

4. What energy carrying molecule is produced? How many?

5. What happens to the acetyl-CoA formed as the end product?

6. Are the transition reactions anaerobic or aerobic?

D. What happens in the Krebs cycle (also known as the citric acid cycle)?

1. Where do the Krebs cycle reactions take place?

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VI. How does anaerobic respiration differ from aerobic respiration?

A. What organisms engage in anaerobic respiration?

B. In what kinds of habitats are they generally found?

VII. How does fermentation differ from aerobic respiration? How does it differ from

anaerobic respiration?

KEY TERMS

adenosine triphosphate

(ATP), p. 73, 80

aerobic, p. 80

aerobic respiration, p. 85

alcohol fermentation, p. 87

anabolism, p. 66

citric acid cycle (Krebs cycle),

p. 82, 83

crassulacean acid metabolism

(CAM), p. 79

cyclic electron transport,

p. 75

mesophyll, p. 68

metabolism, p. 66

nicotinamide adenine

dinucleotide phosphate,

p. 73

noncyclic electron

TEACHING TIPS

2. For a lab activity or in lecture if you have time, demonstrate the visible light spectrum with a

prism and different colored filters (you can use colored cellophane). First use the prism to