plants and photosynthesis

• What is photosynthesis?

  A series of enzyme-controlled reactions in plants
• What role does chlorophyll play in photosynthesis?

  It absorbs light energy for the reaction
• What organ is primarily responsible for photosynthesis?

  The leaf
• What happens to leaves kept in the dark for 24 hours?

  They become destarched
• How can you test a leaf for starch?

  By using iodine to check for blue/black color
• What are the steps to test a leaf for starch?

  1. Boil the leaf to kill it
  2. Decolourise using ethanol
  3. Wash to soften
  4. Test with iodine for blue/black color
• Why do plants need certain minerals?

  For healthy growth
• What is the role of water in plants?

  Used in photosynthesis and transport of minerals
• How does water support plant cells?

  By filling vacuoles to keep cells turgid
• What is transpiration in plants?

  Loss of water vapor from leaves
• What increases the surface area for water absorption in roots?

  Root hairs
• How are minerals transported into root cells?

  By active transport
• What does the xylem do in plants?

  Carries water in one direction up the plant
• What factors affect the rate of transpiration?

  • Temperature
  • Humidity
  • Wind speed
• What do stomata do in plants?

  Allow gas exchange and prevent water loss
• What are limiting factors in photosynthesis?

  Conditions that restrict the rate of photosynthesis
• How does temperature affect the rate of photosynthesis?

  Increases to an optimum, then decreases
• How is light intensity investigated in photosynthesis?

  By moving a plant closer to a light source
• What happens to the rate of photosynthesis as light intensity increases?

  It increases until another factor limits it
• How does carbon dioxide concentration affect photosynthesis?

  Increases the rate until another factor limits it
• What are the products of photosynthesis?

  • Glucose
  • Oxygen (a byproduct)
• What is the role of chlorophyll in photosynthesis?

  It captures light energy
• What can glucose be transformed into in plants?

  • Cellulose
  • Proteins
  • Oils
  • Stored as starch
  • Used in respiration
• What are the growth problems caused by mineral deficiencies?

  • Nitrates: Poor growth
  • Potassium: Yellowing of leaf
  • Phosphates: Poor root growth