Plants and photosynthesis

• What is the chemical reaction that allows photosynthetic organisms to produce glucose?

  Photosynthesis
• How is photosynthesis controlled?

  By enzymes
• What happens to photosynthesis if it gets too hot?

  Photosynthesis stops due to enzyme denaturation
• Where does photosynthesis occur in plants?

  In chloroplasts
• What do we call organisms capable of photosynthesis?

  Photosynthetic organisms
• What is absorbed through the leaves of the plant?


  Carbon dioxide
• How is water absorbed by plants?

  Through the roots
• What pigment absorbs light energy in chloroplasts?

  Chlorophyll
• What are the uses of glucose produced in photosynthesis?

  • Cellulose for cell walls
  • Making proteins
  • Stored as fats or oils in seeds
  • Stored as starch in roots
• What is the method for testing a leaf for starch?

  1. Boil the leaf in water for 30 seconds
  2. Add the leaf to boiling ethanol
  3. Wash with water
  4. Add iodine solution
  5. Observe color change to blue/black
• What is a limiting factor in photosynthesis?

  A factor that reduces the rate of photosynthesis
• What happens to the rate of photosynthesis as CO2 increases?

  It increases up to a point
• What could limit photosynthesis after CO2 is no longer a factor?

  Light intensity or temperature
• What is the method to investigate how light intensity affects the rate of photosynthesis?

  1. Place Elodea in water with sodium hydrogen carbonate
  2. Use a funnel and test tube setup
  3. Position a lamp at various distances
  4. Record oxygen bubbles produced in one minute
• How does light intensity affect the rate of photosynthesis?

  It increases up to a point
• What happens to enzymes at low temperatures?

  They work slowly
• What occurs after the optimum temperature for photosynthesis?

  Enzymes denature and rate decreases
• What are the environmental factors affecting transpiration?

  • Light intensity
  • Temperature
  • Air flow
  • Humidity
• What is transpiration?

  The loss of water from the plant
• What is the method for investigating transpiration using a potometer?

  1. Set up potometer with water
  2. Cut stem underwater and fit into potometer
  3. Apply Vaseline to joints
  4. Record air bubble movement over time
• How does light affect the transpiration rate?

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

  Higher temperature increases transpiration rate
• How does wind affect the transpiration rate?

  Stronger wind increases transpiration rate
• How does humidity affect the transpiration rate?

  Higher humidity decreases transpiration rate
• What is the function of xylem in plants?

  Transport water and minerals
• What is the function of phloem in plants?

  Transport food substances
• How do root hair cells absorb water?

  By osmosis
• What is the process by which minerals move into the root?

  Active transport
• What do fertilizers provide for plants?

  Essential minerals for growth
• What do NPK values indicate in fertilizers?

  Proportions of nitrates, phosphates, potassium
• What is the role of nitrates in plants?

  Needed to make amino acids
• What is the role of phosphates in plants?

  Needed to make DNA and cell membranes
• What is the role of potassium in plants?

  Involved in enzymes for respiration
• What symptoms indicate nitrogen deficiency in plants?

  Poor growth and yellow leaves
• What symptoms indicate phosphorus deficiency in plants?

  Poor root growth and discolored leaves
• What symptoms indicate potassium deficiency in plants?

  Poor growth of fruit and flowers