Lecture Notes: Photosynthesis and Plant Adaptations

Introduction

• Discussion about wanting special abilities of organisms
• Unique abilities of plants, focusing on photosynthesis
• Importance of photosynthesis for life on Earth
  • Contributes to oxygen production
  • Essential for plant survival, major producers in food webs
  • Source of many medications and foods

Photosynthesis Overview

• Process allows plants to make their own food (glucose)
• Not exclusive to plants, also done by some protists and bacteria
• Balanced equation of photosynthesis compared to aerobic cellular respiration
  • Reactants and products of photosynthesis and cellular respiration

Light Capturing and Chlorophyll

• Plants capture light using pigments, primarily chlorophyll
• Visible light wavelengths and color absorption by pigments
  • Chlorophyll absorbs red and blue light, reflects green light
  • Other pigments also present, contributing to diverse plant colors

Photosynthesis Reactions

Light-Dependent Reactions

• Occur in thylakoids within chloroplasts
• Light is captured, water is split into electrons, protons, and oxygen
• Produces ATP and NADPH for the next stage

Light-Independent Reactions (Calvin Cycle)

• Occur in the stroma of chloroplasts
• Involves carbon fixation: converting CO2 into an organic form
• ATP and NADPH from light-dependent reactions provide energy and reducing power
• Results in the production of glucose

Photosynthesis Equation Review

• Review of the photosynthesis equation
• CO2 involvement in Calvin Cycle, glucose production as a final product

Plant Adaptations for Photosynthesis

• Adaptations help plants perform photosynthesis in diverse environments
• Diversity in leaf shapes, coverings, and pigments
• CAM Photosynthesis Example:
  • Adaptations of cacti in hot deserts
  • Stomata open at night to reduce water loss
  • Chemical storage of captured CO2 for use during the day

Conclusion

• Encouragement to explore more details about photosynthesis
• Mention of further reading and resources
• Reminder to stay curious