Plants

• Photosynthesis word equation: carbon dioxide + water --> (sunlight) glucose + oxygen
• Photosynthesis chemical equation: 6CO2 + 6H2O --> C6H12O6 + 6O2
• 3 factors that affect the rate of photosynthesis:

  1. Light intensity
  2. Amount of CO2
  3. Temperature
• If temperatures go over 45 degree celsius, enzymes denature and growth of plant is stunted
• Waxy cuticle:

  • Prevents water loss
  • Allows light through
• Upper epidermis:

  • Transparent layer allows light through
  • Protective layer prevents pathogens from entering
• Palisade mesophyll:

  • Contains large number of chloroplasts
  • Allows maximum absorption of light
• Spongy mesophyll:

  • Large air spaces allows air circulation around the cell
  • Carbon dioxide diffuses in cell
• Lower epidermis:

  • Pores (stomata) allows carbon dioxide in the leaf
  • Guard cells can close pores to reduce water loss
• Xylem:

  • Brings water to leaf
• Phloem:

  • Takes away some products of photosynthesis for other plants to use
• Plants mainly require 2 minerals: nitrogen (nitrate ions) and magnesium (magnesium ions)
• Nitrogen (nitrate ions)

  • makes amino acids
  • produces some enzymes
  • makes DNA and some hormones
• Nitrogen deficiency in plants:

  • Older leaves turn yellow and die
  • Growth is stunted
• Magnesium (magnesium ions)

  • Produces chlorophyll
  • Helps some enzymes to function
  • Produces nucleic acids
• Magnesium deficiency in plants:

  • Leaves turn yellow
  • Growth is slowed
• A vascular bundle consists of both xylem and phloem