Photosynthesis

PHOTOSYNTHESIS


Photosynthesis is a series of 2 reactions that can be summarised using the following equation:
 Carbon Dioxide + Water =====>  Glucose + Oxygen
  6CO2  +  6H2O ===> C6H12O6 + 6O2
•The first reaction only happens when light energy is present and the second reactions can happen without sunlight.
•As photosynthesis reactions need sunlight energy, the reactions are said to be ENDOTHERMIC.
PHOTOSYNTHESIS AND CHLOROPLASTS
•Photosynthesis happens in organelles called Chloroplasts which contain a green substance called chlorophyll.
•Chlorophyll absorbs sunlight energy so that photosynthesis can happen.
This means that any part of a plant that is green will contain chloroplasts and so produce sugars like GLUCOSE and SUCROSE through photosynthesis.
Only plants have the ability to transfer light energy into chemical energy so they are called PRODUCERS and are the source of all energy on the planet
https://www.youtube.com/watch?v=VeU7ULL9Usw click on this to see Test for starch in leaf.
WHAT ARE GLUCOSE AND SUCROSE USED FOR?
•Glucose and sucrose are transported in phloem vessels around plants to parts that do not carry out photosynthesis e.g. roots and non-green parts.
•The glucose is used in respiration to provide energy for plant processes
•Any excess glucose is stored as insoluble starch in every plant cell.
•The starch will be broken back down into glucose at night and then used in respiration as plants cannot carry out photosynthesis as night.
WHAT DO PLANTS NEED ENERGY FOR?
•Building glucose into starch for storage
•Building sugars into cellulose, which strengthens cell walls.
•Combining sugars with nitrate ions and other minerals to make amino acids for protein synthesis.
•Building fats and oils for storage
WHAT HAPPENS TO THE OXYGEN THAT IS MADE?
•Some of the oxygen is used in respiration

•Some oxygen diffuses out of the leaf through stomata into the atmosphere.

FACTORS THAT AFFECT THE RATE OF 

PHOTOSYNTHESIS



WHAT FACTORS AFFECT THE RATE OF PHOTOSYNTHESIS?
•Light intensity
•Carbon dioxide concentration
•Temperature

Light Intensity

Increasing light intensity increases the rate of photosynthesis where either temperature of CO2 concentration becomes limiting. 
Carbon-dioxide Concentration

Increasing CO2 concentration increases the rate of photosynthesis when either temperature or light intensity becomes limiting.

Temperature

      photosynthesis is controlled by enzymes and enzymes are affected by temperature. As you increase the temperature the enzyme work faster making photosynthesis happen faster. Above the optimum temperature the enzyme denature making photosynthesis slow down and stop.






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