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Chapter 6: Energy Flow in the Life of a Cell At a Glance

Case Study: Energy Unleashed

6.1 What Is Energy?

• The Laws of Thermodynamics Describe the Basic Properties of Energy
• Living Things Use the Energy of Sunlight to Create the Low-Entropy Conditions Characteristic of Life

6.2 How Does Energy Flow in Chemical Reactions?

• Exergonic Reactions Release Energy
• Endergonic Reactions Require an Input of Energy
• Coupled Reactions Link Exergonic and Endergonic Reactions

6.3 How Is Cellular Energy Carried Between Coupled Reactions?

• ATP Is the Principal Energy Carrier in Cells
• Electron Carriers Also Transport Energy Within Cells

6.4 How Do Cells Control Their Metabolic Reactions?

• At Body Temperatures, Spontaneous Reactions Proceed Too Slowly to Sustain Life
• Catalysts Reduce Activation Energy
• Enzymes Are Biological Catalysts
• The Structure of Enzymes Allows Them to Catalyze Specific Reactions
• Cells Regulate the Amount and the Activity of Their Enzymes
• The Activity of Enzymes Is Influenced by Their Environment

Case Study Revisited: Energy Unleashed

Links to Life: Lack of an Enzyme Leads to Lactose Intolerance