specialised cells

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  • specialised cells
    • palisade leaf cell
      • adapted with chloroplasts for photosynthesis; nearer the top of the cell to get more light
        • tall shape: more surface area to absorb carbon dioxide from the atmosphere
          • thin; this means you can pack more of them at the top of the leaf as this is where more photosynthesis happens
    • guard cells
      • adapted to open and close pores
        • kidney shape which opens and closes the stomata (pores) in  aleaf
          • when there is lots of water the guard cells will fill up and become turgid: the stomata will open so gases can be exchamhed for photosynthesis
            • if the plant is short of water the guard cells lose more water and become flaccid, this closes the stomata to help prevent the loss of too much water.
      • thin outer walls and thicker inner walls make the opening and closeing work
      • sensitive to light so they close at night: saving water without losing out on photosynthesis
      • adapted for gas exchange and controlling water loss within a leaf
    • red blood cells
      • concave shape gives a big surface area for absorbing oxygen, this also lets them pass easily through capillaries
      • packed with haemoglobin which absorbs the oxygen
        • have no nucleus leaving more room for haemoglobin
    • sperm and egg cells
      • egg cell:carries DNA and nourishes developing embryos, contains food reserves to feed embryo
        • when a sperm fuses with egg the egg changes shape so that no other sperm cells can get in ensuring the right amount of DNA.
      • sperm: male DNA to female DNA. long tail and a streamlined head to help it swim to the egg. lots of mitochondria to provide energy
        • enzymes in the head to digest through the egg cell membrane.


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