Notes on Photosynthesis

Introduction

• Daydreaming about special abilities in nature
• Desire to have the ability of photosynthesis
• Photosynthesis is not exclusive to plants; some protists and bacteria can also do it
• Essential for producing oxygen and crucial in food webs

Importance of Photosynthesis

• Plants are major producers
• Source of medications and food
• Helps in understanding how plants synthesize glucose

Photosynthesis Overview

• Plants make their own glucose via photosynthesis
• Equation for photosynthesis resembles that of cellular respiration
• Plants produce glucose without needing to search for it

The Process of Photosynthesis

Key Components

• Light capturing molecules are called pigments
• Chlorophyll:
  • Absorbs red and blue light; reflects green
  • Found in chloroplasts
• Chloroplasts:
  • Contains two major processes:
    1. Light-dependent reactions
    2. Light-independent reactions (Calvin cycle)

Light-Dependent Reactions

• Occur in thylakoids
• Light is captured, and water is split
• Products:
  • ATP
  • NADPH
  • Oxygen (waste product)

Light-Independent Reactions (Calvin Cycle)

• Occur in the stroma
• Carbon dioxide enters through stomata
• Requires ATP and NADPH from light-dependent reactions
• Converts fixed carbon dioxide into glucose

Further Exploration

• Photosystems in light-dependent reactions
• Detailed steps in Calvin cycle
• Conversion of ATP and NADPH back to ADP and NADP+

Plant Adaptations for Photosynthesis

• Diversity in leaf shapes, coverings, and pigments
• Example: Cacti
  • Adaptation to hot desert environments
  • Employ CAM photosynthesis:
    • Stomata open at night for CO2 capture
    • Allows stomata to remain closed during the day to minimize water loss

Conclusion

• Photosynthesis is a complex but fascinating process
• Encouragement to stay curious and explore further.