Chapter 3: Bioenergetics

OBJECTIVES

By studying this chapter, you should be able to do the following:

1. Discuss the function of the cell membrane, nucleus, and mitochondria.

2. Define the following terms: (1) endergonic reactions, (2) exergonic reactions, (3) coupled reactions, and (4) bioenergetics.

3. Describe the role of enzymes as catalysts in cellular chemical reactions.

4. List and discuss the nutrients that are used as fuels during exercise.

5. Describe the structure and function of ATP in the cell.

6. Discuss the biochemical pathways involved in anaerobic ATP production.

7. Describe the aerobic production of ATP.

8. Describe how the metabolic pathways involved in bioenergetics are regulated.

9. Discuss the interaction between aerobic and anaerobic ATP production during exercise.

10. Identify the enzymes that are considered rate limiting in glycolysis and the citric acid cycle.

OUTLINE

• Cell Structure 41

  • Biological Energy Transformation 41

  • Cellular Chemical Reactions 42

  • Oxidation–Reduction Reactions 44

  • Enzymes 45

• Fuels for Exercise 48

  • Carbohydrates 48

  • Fats 49

  • Proteins 49

• High-Energy Phosphates 49

• Bioenergetics 50

  • Anaerobic ATP Production 51

  • Aerobic ATP Production 54

• Aerobic ATP Tally 61

• Efficiency of Oxidative Phosphorylation 62

• Control of Bioenergetics 62

  • Control of ATP-PC System 63

  • Control of Glycolysis 63

  • Control of Citric Acid Cycle and Electron Transport Chain 64

• Interaction Between Aerobic/Anaerobic ATP Production 64

KEY TERMS

acetyl-CoA

activation energy

adenosine diphosphate (ADP)

adenosine triphosphate (ATP)

aerobic

anaerobic

ATPase

ATP-PC system

beta oxidation

bioenergetics

cell membrane

chemiosmotic hypothesis

citric acid cycle (also called the Krebs cycle)

coupled reactions

cytoplasm

electron transport chain

endergonic reactions

enzymes

exergonic reactions

flavin adenine dinucleotide (FAD)

glucose

glycogen

glycogenolysis

glycolysis

inorganic

inorganic phosphate (P_i)

isocitrate dehydrogenase

Krebs cycle (also called citric acid cycle)

lactate

metabolism

mitochondrion

molecular biology

nicotinamide adenine dinucleotide (NAD⁺)

nucleus

organic

oxidation

oxidative phosphorylation

phosphocreatine (PC)

phosphofructokinase (PFK)

reduction

INTRODUCTION

Thousands of chemical reactions occur throughout the body during each minute of the day. Collectively, these reactions are called metabolism. Metabolism is broadly defined as the total of all cellular reactions and includes chemical pathways that result in the synthesis of molecules (anabolic reactions), as well as ...