Lecture on Photosynthesis

Introduction

• Desire for special abilities from nature such as flying or walking on walls.
• Unique ability of plants: photosynthesis.
  • Also performed by some protists and bacteria.
• Importance of photosynthesis:
  • Produces oxygen needed by animals and amoebas.
  • Plants are major producers in food webs, crucial for medications and foods.

Photosynthesis Process

• Photosynthesis allows plants to produce glucose.
• Animals obtain glucose from food, while plants create their own via photosynthesis.

Photosynthesis Equation

• Similarities with aerobic cellular respiration:
  • Both processes have linked reactants and products.
  • Cellular respiration is used to make ATP.

Light Capture in Plants

• Plants use pigments to capture light:
  • Visible light has different wavelengths/colors.
  • Chlorophyll absorbs red and blue light; reflects green.
  • Other pigments capture different light wavelengths.

Photosynthesis Reactions

Light Dependent Reactions

• Occur in thylakoids in chloroplasts:
  • Granum (singular), Grana (plural) are stacks of thylakoids.
• Captures light, splits water to produce oxygen, ATP, and NADPH.

Light Independent Reactions (Calvin Cycle)

• Occur in chloroplast stroma.
• Carbon dioxide is taken through stomata:
  • Stomata can open/close to regulate entry.
• Carbon fixation: converting CO2 to organic form using ATP and NADPH.
• Produces glucose through complex pathways.

Key Equations

• Light Dependent Reactions produce ATP and NADPH.
• Calvin Cycle uses CO2, ATP, NADPH to produce glucose.

Enhancing Photosynthesis

• Photosynthesis adaptations in plants:
  • Leaf shapes, coverings, pigments.
  • Example: CAM photosynthesis in cacti:
    • Stomata open at night to minimize water loss.
    • Stores CO2 for use during the day.

Conclusion

• Importance of photosynthesis in various environments.
• Encouragement to explore more details about the process and plant adaptations.

• Note: Further reading links available for detailed study on photosystems and Calvin Cycle steps.