🌱

Cellular Respiration and Photosynthesis Overview

Mar 26, 2025

Note Summary for Lecture on Cellular Respiration and Photosynthesis

Introduction

  • Cellular Respiration and Photosynthesis are two fundamental biochemical processes in biology.
  • They are crucial for the energy transformation and sustaining life.

Cellular Respiration

  • Defined as the process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.
  • Stages of Cellular Respiration:
    • Glycolysis
      • Occurs in the cytoplasm.
      • Converts glucose into pyruvate.
      • Produces a small amount of ATP and NADH.
    • Krebs Cycle (Citric Acid Cycle)
      • Takes place in the mitochondria.
      • Pyruvate is further broken down.
      • Produces CO2, ATP, NADH, and FADH2.
    • Electron Transport Chain (ETC)
      • Located in the inner mitochondrial membrane.
      • Uses NADH and FADH2 to create a proton gradient.
      • Produces a significant amount of ATP via oxidative phosphorylation.

Photosynthesis

  • The process by which green plants, algae, and some bacteria convert light energy, water, and carbon dioxide into glucose and oxygen.
  • Two Main Phases of Photosynthesis:
    • Light-dependent Reactions
      • Occur in the thylakoid membranes of chloroplasts.
      • Use light energy to produce ATP and NADPH.
      • Oxygen is released as a byproduct.
    • Calvin Cycle (Light-independent Reactions)
      • Occurs in the stroma of chloroplasts.
      • Uses ATP and NADPH to convert CO2 into glucose.

Importance in Ecology

  • Interdependence of Photosynthesis and Cellular Respiration:
    • Photosynthesis provides the oxygen and organic compounds used in cellular respiration.
    • Cellular respiration releases CO2, which is used in photosynthesis.
  • Crucial for maintaining atmospheric oxygen and carbon dioxide balance.

Conclusion

  • Both processes are essential for energy flow in ecosystems.
  • Understanding these processes is key to grasping biological energy conversion and ecological balance.