GCSE Biology

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  1. cell membrane
    controls what enters and leaves the cell
  2. glucose
    energy source for plants to make their own food
  3. oxygen
    the colourless gas which plants produce during photosynthesis 
  4. chloroplasts 
    the small structures inside a cell where photosynthesis takes place 
  5. cell sap
    a micture of sugras and water found inside a vacuole
  6. photosynthesis is a chemical reaction and so has a rate . the rate of photosynthesis varies depending on the three main factors :
    • light 
    • carbon dioxide
    • temperature 
  7. light energy has to be absorbed by .... for photosynthesis to take place . the ..... the light , the more light energy there is . more light energy means that the rate of photosnthesis is .....
    • chlorophyll 
    • brighter 
    • faster 
  8. carbon dioxide is on eof the raw materials used by plants to make their food . the concentration of carbon dioxide in the air (....) is actually quite low 
  9. more carbon dioixde means 
    more photosnythesis , so plants make more food and crow quicker 
  10. photosynthesis is controlled by
  11. enzymes usually work best at 
    warmer temperatures . if the temperature gets too hot above 40°C , plant enzymes begin to break down and are destroyed or denatured 
  12. what is the ideal combination of factors for the maximum rate of photosynthesis 
    • enough light 
    • enough carbon dioixde
    • ideal temperature (not too hot or too cold)

    • if one of the factors is restricted , the rate of photosynthesis will be below the maximum possible rate 
    • the restricted factor controls how quickly photosynthesis occurs and so limits the rate . It is called the limitating factor 
  13. annote the below graphy to show how the amount of light affects the rate of phtosynthesis 
    Image Upload 1
    Image Upload 2
  14. annote the below graphy to show the amount of carbon dioxide affects the rate of phtosynthesis
    Image Upload 3
    • at A carbon dioxide is the limitating factor 
    • at B carbon dioixde stops becoming the limitating factor and now temperature or carbon dioxide is the limitating factor
  15. annote the below graphy to show how temperature affects the rate of phtosynthesis 
    Image Upload 4
    • at A temperature is a limitating factor 
    • at B temperature stops becoming a limitating factor 
    • at C once the temperature exceeds this optimal temperature, the enzyme begins to denature, thus lowering the rate at which photosynthesis occurs , so once again temperature is a limitating factor 
  16. glucose is used in respiration to make
    • energy 
    • glucose + oxygen --> (energy) + carbon dioxide + water
    •                                                 (waste)              (waste)
    • energy is used to build new cells for growth or repair of damaged cells . some energy is used in chemical reactions to change some materials into others . more energy is used to move materials around inside the plant 
  17. glucose can be used in proteinsynthesis
    • all living cells need proteins to form enzymes and cell membranes . they also need proteins for growth . plant and algal cells can synthesize proteins from glucose and other raw materials such as nitrates . soluble nitrates can be absorbed through cell membranes from soil or water (if the plant is aquatic) 
    • glucose + nitrogen --> proteins
  18. glucose can be converted to starch 
    a plant wont use all the glucose it makes straight away . Some glucose needs to be converted to starch and stored for times when the plant cant make enough glucose , for instance when it's cold . 
  19. why is starch an energy store
    because the plant can change the starch back to glucose when it needs more energy (glucose) for respiration
  20. why is stracj useful for storage
    its insoluble and large so cant diffuse through the cell membrane and wont react easily with other chemicals in the cytoplasm
  21. where is starch stored in cabbage
    in the leaves
  22. where is tsrach stored in carrots
    in the roots
  23. where is strach stored in brocili
    in the flowera
  24. where is strach stored in potatoes
    potatoes are stem tubers full of starch
  25. glucose is converted into lipids
    some seeds , plants and algae store energys as fat or oil droplets in the cytoplasm . Fats and oils belong to a group called lipids .1g of lipid has a higher energy content than 1g of carbohydrate . lipids provide more glucose for respiration than carbohydrates , such as starch , when cells need it for respiration 
  26. glucose is used for the photosynthesis of cellulose 
    when large molecules of cellulose are synthesized many molecules of glucose are linked together to form strong fibres . this makes cellulose a useful strcutural material in plant and algal cell walls . it strengthens the cell wall and prevents the cell wall bursting when it absorbs water . cellulose can be used to make and repair cells 
  27. the faster the rate of photosynthesis , the
    better the growth of the plants , the higher the yield . Yield is the amount of crop a plant produces . 
  28. growers can get plants photsyntehsizing all year round . they can do this by 
    enhancing light , carbon dioxide concentration and temperature
  29. what are hydrophonics 
    in hydrophonics the water , nutrients and air needed by the plant to grow are delivered straight to the plants roots , freeing the plant to use its available energy in its upper leaf , fruit or flower development . In short this allows you to crow up to 10* the yeild , in half the space and half the time 
Card Set:
GCSE Biology
2012-09-08 12:58:59
photosynthesis part three

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