Photosynethesis

• What does Photosynthesisdo? Where does it take place and what is the process?

  1. Takes place in leaves

  2. Takes place in chloroplasts

  3. Chlorophyll absorbs light

  4. Converts carbon dioxide and water into glucose and oxygen
• Photosynthesis requires light energy
• Endothermic reaction


  Reaction where energy is transferred from the environment
• How plant gets reactants for photosynthesis

  1. Carbon dioxide diffuses into leaves through stomata

  2. Water is taken up from soil by roots and transported to leaves via xylem
• Uses of glucose


  • Cellular respiration
  • Making cellulose
  • Making starch
  • Making amino acids
  • Making oils and fats
• Plant growth rate often depends on rate of photosynthesis
• Factors affecting rate of photosynthesis are light intensity, temperature, carbon dioxide concentration, and amount of chlorophyll
• What are the products of Photosynethesis?


  Glucose and oxygen
• Photosynthesis


  The reaction that plants use to trap light energy
• Plants use light for their source of energy
• Photosynthesis


  • It is an endothermic reaction
  • It takes place in the leaves of a plant
  • Leaves contain the green chemical chlorophyll
• Photosynthesis


  1. Plant takes in carbon dioxide and water

  2. Light energy is absorbed by chlorophyll

  3. Light energy is used to convert carbon dioxide and water into glucose

  4. Oxygen is also produced
• Chemical formulas


  • Carbon dioxide (CO2)
  • Water (H2O)
  • Glucose (C6H12O6)
  • Oxygen (O2)
• Light intensity increases


  Rate of photosynthesis increases
• Limiting factor


  The factor that is in short supply and is limiting the rate of photosynthesis
• Carbon dioxide level increases

  Rate of photosynthesis increases
• Factors affecting rate of photosynthesis


  • Light intensity
  • Carbon dioxide level
  • Amount of chlorophyll in leaf
  • Temperature
• As temperature increases, enzymes involved in photosynthesis work faster, but if temperature keeps increasing, enzymes will denature and rate of photosynthesis will fall
• What is the word equation for photosynthesis?

  Carbon dioxide + water + sunlight -> glucose + oxygen
• What factors affect photosynethesis?


  Chlorophyll, limiting factors= light intensity, carbon dioxide, temperature.
• Why will less chlorophyll affect the rate of photosynthesis?


  . If plants have less of this, they can't carry out as much photosynthesis.
• Why might there be low amounts of chlorophyll in plants? What will they make?


  Disease( Tobacco Mosaic Virus). Environmental Stress Lack of nutrients (water) These will make damaged chloroplasts, meaning they cant make as much chlorophyll.
• What happens if the rate of intensity increases?

  Rate of Photosynthesis also increases
• What does the term Plateaued mean?

  Something else is limiting photosynthesis
• Why does the rate of photosynthesis increase when there is more carbon dioxide?

  CO2 is a reactant for photosynthesis, so the more CO2, the higher the rate.
• How is temperature a limiting factor?


  enzymes work more quickly> molecules move faster> enzymes denature

  
• Investigating the effect of light intensity on the rate of photosynthesis


  1. Take a boiling tube and place it 10 cm away from an LED light source

  2. Fill the boiling tube with sodium hydrogen carbonate solution

  3. Put a piece of pond weed into the boiling tube

  4. Leave for 5 minutes to acclimatize

  5. Count the number of bubbles produced in 1 minute
• Repeating the experiment at different distances


  1. Repeat the experiment at 20 cm, 30 cm, and 40 cm from the light source

  2. Calculate the mean number of bubbles produced per minute at each distance
• Problems with counting bubbles


  • Number of bubbles can be too fast to count accurately
  • Bubbles are not always the same size
• Measuring the volume of oxygen produced

  1. Place the pond weed in a measuring cylinder filled with water

  2. Measure the volume of oxygen produced