Comprehensive Notes on Photosynthesis and Plant Biology

Parts of a Plant

• Shoot system
  • Flower
    • Helps in reproduction
  • Leaf
    • Performs photosynthesis
  • Fruit
    • Protects the seeds
  • Stem
    • Supports the plant
• Root system
  • Root
    • Absorbs water and minerals

Leaf Cross Section

• Mesophyll
• Vein
• Stomata
  • $CO<em>2$ and $O</em>2$ exchange
• Mesophyll cell

Photosynthesis

• Chemical energy + Carbon dioxide = Sugar
• Vein
  • Xylem (Water transport)
  • Phloem (Sugar transport)
• Stoma
• Process:
  1. Chloroplasts trap light energy.
  2. Water enters the leaf.
  3. Carbon Dioxide $CO_2$ enters the leaf.
  4. Sugar leaves the leaf.

Chloroplast Structure

• Stroma
• Granum
• Thylakoid
• Thylakoid space
• Chloroplast
  • Single mesophyll cell
  • Outer membrane
  • Intermembrane space
  • Inner membrane

Granum and Thylakoid

• Granum
• Stroma
• Thylakoid
• Thylakoid membrane

The Electromagnetic Spectrum

• Different forms of electromagnetic energy have different wavelengths.
• Shorter wavelengths have more energy than longer wavelengths.
• Ranges:
  • Gamma rays: $10^{-5}$ nm
  • X-rays: $10^{-3}$ nm
  • UV: $1$ nm
  • Visible light: 400-700 nm
    • 400 nm
    • 500 nm
    • 600 nm
    • 700 nm
  • Infrared
  • Microwaves
  • Radio waves: $10^6$ km

Light Reflection and Transmission

• Reflected light
• Transmitted light
• Green light is reflected and transmitted more than other colors.
• A leaf containing chloroplasts appears green in color.

Absorption Spectra of Photosynthetic Pigments

• Pigments:
  • Chlorophyll a
  • Chlorophyll b
  • Carotenoids
  • Phycocyanin
  • Phycoerythrin
• Wavelength of light (nanometers)
  • 400 - 700

Photosynthesis Overview

• Light
• $H_2O$
• Chloroplast
  • ATP
  • $NADPH_2$
• Calvin cycle
  • $NADP^+$
  • ADP+P
• Sugar

Photosynthesis Parts

• Photosynthesis is divided into two parts
  • The overall reaction in photosynthesis:
    • $6CO<em>2 + 12 H</em>2O + Light \rightarrow C<em>6H</em>{12}O<em>6 + 6O</em>2 + 6 H_2O$
• Two components:
  • Light-dependent reactions
    • $H<em>2O \rightarrow O</em>2$ (ATP, NADPH)
  • Light-independent reactions
    • $CO<em>2 \rightarrow (C</em>6H<em>{12}O</em>6)$
  • Energy Harvest and Synthesis