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Chapter 7 of Class 9 Biology, titled Bioenergetics, focuses on the study of energy flow and transformation in biological systems. This chapter explains how organisms obtain, convert, and utilize energy to sustain life processes.
Key general concepts covered in this chapter include:
- Definition of Bioenergetics: Bioenergetics is the field that studies how living organisms manage their energy needs through biochemical processes.
- Sources of Energy: The chapter discusses various energy sources for organisms, primarily sunlight for plants (through photosynthesis) and food for animals (through cellular respiration).
- Photosynthesis: This process is explored as a critical mechanism by which plants convert light energy into chemical energy stored in glucose. The chapter outlines the stages of photosynthesis, including light-dependent reactions and the Calvin cycle.
- Cellular Respiration: The process by which organisms break down glucose in the presence of oxygen to release energy is discussed. This includes the stages of glycolysis, the Krebs cycle, and oxidative phosphorylation.
- Energy Currency: The chapter highlights the role of adenosine triphosphate (ATP) as the primary energy currency in cells, explaining how ATP is produced during cellular respiration and how it is used for various cellular activities.
- Importance of Energy Transformation: The significance of efficient energy transformation for growth, reproduction, and maintenance of homeostasis in living organisms is emphasized.
This chapter helps students understand the fundamental principles of energy flow in living systems and the importance of energy transformations in sustaining life.