Overview
The lecture covers the fundamental processes of photosynthesis and cellular respiration, including their chemical reactions, importance, and main stages.
Photosynthesis: Overview
- Photosynthesis is the process by which plants convert light energy, water, and carbon dioxide into glucose and oxygen.
- Occurs primarily in the chloroplasts of plant cells.
- The overall chemical equation: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂.
- Light energy is absorbed by chlorophyll, the green pigment in plants.
Main Reactions of Photosynthesis
- Photosynthesis consists of two stages: light-dependent reactions and the Calvin cycle (light-independent reactions).
- Light-dependent reactions capture sunlight to produce ATP and NADPH, releasing O₂ as a byproduct.
- The Calvin cycle uses ATP and NADPH to convert CO₂ into glucose.
Cellular Respiration: Overview
- Cellular respiration is the process of converting glucose and oxygen into ATP, water, and carbon dioxide.
- Occurs in the mitochondria of eukaryotic cells.
- The overall chemical equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP.
Main Reactions of Cellular Respiration
- Includes glycolysis, the Krebs cycle (citric acid cycle), and the electron transport chain.
- Glycolysis breaks glucose into pyruvate, producing some ATP and NADH.
- The Krebs cycle produces electron carriers and CO₂ from pyruvate.
- The electron transport chain uses electrons to generate most ATP and forms water.
Relationship and Significance
- Photosynthesis and cellular respiration are complementary; the products of one serve as the reactants of the other.
- Together, these processes support the flow of energy in ecosystems.
Key Terms & Definitions
- Photosynthesis — process where plants make glucose using sunlight, water, and CO₂.
- Chloroplast — cell organelle where photosynthesis occurs.
- Chlorophyll — pigment absorbing sunlight for photosynthesis.
- Calvin cycle — light-independent stage of photosynthesis producing glucose.
- Cellular respiration — process of breaking down glucose for ATP energy.
- Mitochondria — organelle where cellular respiration takes place.
- Glycolysis — first stage of cellular respiration splitting glucose.
- Krebs cycle — second stage of cellular respiration producing electron carriers.
- Electron transport chain — final stage generating most ATP.
Action Items / Next Steps
- Review chemical equations and stages of both processes.
- Complete assigned readings or videos on photosynthesis and cellular respiration reactions.
- Prepare to discuss how these processes are interdependent in ecosystems.