B4

• Photosynthesis

  carbon dioxide + water

  =light energy=>

  glucose + oxygen
• Chlorophyll


  a green substance found in chloroplasts which absorbs light energy
• Carbon dioxide and Water

  these substances are converted into glucose
• Oxygen


  by-product of photosynthesis
• Limiting factors

  light intensity,temperature and concentration of carbon dioxide
• Light intensity


  this provides energy needed for photosynthesis causing rate to increase up to a certain point at which rate decreases
• Carbon dioxide level


  this is needed for photosynthesis causing rate to increase up to a certain point at which rate stops increasing
• Temperature


  this effects the speed a which enzymes work if enzymes are denatured by high temperature then rate will decrease
• Respiration

  glucose is used for this process as a way of releasing energy
• Cellulose


  glucose is used to make this substance which is found in the cell wall of plant cells
• Proteinsynthesis

  glucose is used to make amino acids for making proteins
• Glucose storage in plants

  glucose is converted into lipids, which are stored in seeds and cells, and starch, which are stored for later use in roots and stems
• Magnesium ions


  making chlorophyll
• Nitrate ions

  building proteins and growth
• light intensity


  The limiting factor shown by this graph is....

  
• Temperature/ CO2 concentration but NOT light.


  On the flat part of the graph what might be the limiting factor?

  
• Low temperature (plenty of sunlight and CO2)


  What is the limiting factor for photosynthesis on a sunny but very cold day?
• Starch storage

  Glucose is converted into this for storage. It is stored in grains.
• osmosis


  This process would cause the cell to swell up if glucose was stored in the cell vacuole.
• Equation for aerobic respiration

  Glucose + oxygen —-> water + carbon dioxide
• Equation for anaerobic respiration

  Glucose ——> lactic acid
• equation for fermentation

  glucose—-> ethanol + carbon dioxide
• symbol equation for photosynthesis

  6CO2 + 6H2O ——> C6H12O6. + 6O2
• What is oxygen debt

  Amount of extra oxygen needed after anaerobic respiration that needs to react with the build up of lactic acid to remove it from cells
• Pondweed experiment

  White light is placed at a distance from the pondweed.

  pondweed is left to photosynthesis for a set time oxygen released will collect in a capillary tube.

  the syringe is used to draw the gas bubble in the tube along a ruler the length of the gas bubble is mea this is proportional to the amount of oxygen produced.