Photosynthesis and Plant Adaptations

• What process do plants use to make their own food?

  Photosynthesis
• What do photosynthetic organisms produce during photosynthesis?

  Glucose and oxygen
• What is the role of glucose in plants?

  It is used to make larger complex molecules
• Where does photosynthesis occur in plants?

  Inside chloroplasts
• What is the function of chlorophyll in photosynthesis?

  It absorbs light energy
• What is the equation for photosynthesis?

  6CO₂ + 6H₂O LIGHT C₆H₁₂O₆ + 6O₂
• Why is photosynthesis considered an endothermic reaction?

  Energy is taken in during the reaction
• What factors affect the rate of photosynthesis?

  Light intensity, CO₂ concentration, temperature
• What does it mean if a factor is a limiting factor in photosynthesis?

  It stops photosynthesis from happening faster
• How can Canadian pondweed be used in experiments?

  To measure the effect of light intensity
• What is the procedure to measure the rate of photosynthesis using Canadian pondweed?

  1. Set up apparatus with an empty gas syringe.
  2. Add sodium hydrogencarbonate to ensure CO₂ supply.
  3. Place a light source at a specific distance.
  4. Allow pondweed to photosynthesize for a set time.
  5. Measure oxygen collected in the gas syringe.
  6. Repeat with different light distances.
• What should be controlled in the pondweed experiment?

  Temperature and carbon dioxide concentration
• How does light intensity affect the rate of photosynthesis?

  Higher light intensity increases the rate
• What happens to the rate of photosynthesis beyond a certain light intensity?

  It levels off due to limiting factors
• What is the inverse square law in relation to light intensity?

  Light intensity is inversely proportional to distance squared
• If the distance from the lamp is halved, how does light intensity change?

  It becomes four times greater
• What is the role of carbon dioxide in photosynthesis?

  It is a raw material needed for photosynthesis
• What happens to the rate of photosynthesis when CO₂ concentration is increased?

  The rate increases up to a point
• What happens to enzymes at temperatures above 45°C?

  They become denatured
• What are the two types of transport vessels in flowering plants?

  • Xylem: transports water and minerals upwards
  • Phloem: transports food substances in both directions
• What is the function of root hair cells?

  To absorb water and minerals
• How do root hairs increase absorption efficiency?

  By providing a large surface area
• What process do phloem tubes use to transport sucrose?

  Translocation
• What is the structure of xylem tubes?

  Made of dead cells with no end walls
• What is transpiration?

  The loss of water from the plant
• How does transpiration affect water movement in plants?

  It creates a shortage that draws water up
• What are stomata and their function?

  Tiny pores for gas exchange in leaves
• How do guard cells regulate stomata?

  By changing shape to control pore size
• How does light intensity affect transpiration rate?

  Brighter light increases transpiration rate
• How does temperature affect transpiration?

  Warmer temperatures increase transpiration rate
• How does air flow influence transpiration?

  Better air flow increases transpiration rate
• How can a potometer be used to estimate transpiration rate?

  1. Set up the potometer and record air bubble position.
  2. Start a stopwatch and measure bubble movement.
  3. Calculate speed of bubble movement for transpiration rate.
• If a potometer bubble moves 25 mm in 10 minutes, what is the transpiration rate?

  2.5 mm min⁻¹
• What should be controlled when using a potometer to measure transpiration?

  Only change one variable at a time
• How does low light intensity affect transpiration?

  It decreases the transpiration rate
• What is the relationship between light intensity and distance from a light source?

  Light intensity decreases as distance increases
• What effect does low carbon dioxide concentration have on photosynthesis?

  It slows down the rate of photosynthesis
• What happens to photosynthesis at temperatures above 45°C?

  Enzymes become denatured
• What is the main product of photosynthesis?

  Glucose
• What gas is released during photosynthesis?

  Oxygen