Cell membranes

Katie  Hughes
Mind Map by Katie Hughes, updated more than 1 year ago
Katie  Hughes
Created by Katie Hughes almost 5 years ago



Resource summary

Cell membranes
  1. Functions
    1. provide a partially permeable membrane
      1. provide structural support
        1. act as channels transporting water soluble substances
          1. allow actrive transport through thorugh carrier proteins
            1. form cell surface receptors for identifying cells
              1. help cells adhere together
                1. act as recpetors
                2. fluid mosaic molecule
                  1. fluid
                    1. individual phospholipids move around within their layer
                    2. mosaic
                      1. pattern produced by scattered proteins when viewed from above
                      2. Phospholipid
                        1. can form sheets (bilayer)
                          1. form membrane bound compartments
                            1. act as a barrier to water soluble substances
                            2. cholesterol
                              1. prevent ions/molecules passing thorugh
                                1. helps regulate fluidity
                                  1. stabilises phospholipid bilayer
                                  2. proteins
                                    1. intrinisic
                                      1. channel
                                        1. carrier
                                        2. extrinsic
                                        3. Glycolipids and glycoproteins
                                          1. short carbohydrate chains attach to lipids and proteins
                                            1. receptors
                                              1. antigens
                                                1. cells adhere
                                              2. transport across cell membranes
                                                1. diffusion
                                                  1. net movement of molecules or ions from a region of high concentration to a gradient of low concentration
                                                    1. occurs down a concentration gradients
                                                      1. result= equilibrium
                                                        1. simple diffusion
                                                          1. molecules pass through the phospholipid bilayer
                                                            1. polar moleculars or ions cannot pass through the bilayer
                                                              1. or large molecules
                                                              2. can get through...
                                                                1. O2
                                                                  1. CO2
                                                                    1. lipid soluble molecules
                                                                      1. oestrogen
                                                                        1. testosterone
                                                                    2. facilitated diffusion
                                                                      1. protein molecules exists in membranes to facilitate diffusion
                                                                        1. channel protein
                                                                          1. transmembrance protein forms tunnel through bilayer
                                                                            1. Na+ Cl- K+
                                                                            2. carrier protein
                                                                              1. change shape to help molecules move in and out cells
                                                                                1. amino acids glucose
                                                                            3. factors effecting diffusion
                                                                              1. concentration gradients
                                                                                1. temperature
                                                                                  1. surface area
                                                                                2. active transport
                                                                                  1. energy from respiration in the form ATP
                                                                                    1. makes carrier proteins change shape
                                                                                      1. reabsorption in kidneys
                                                                                        1. digestion in gut
                                                                                          1. loads sugar in to phloem
                                                                                            1. inorganic ion uptake in root hairs
                                                                                            2. osmosis
                                                                                              1. high water potential to low water potnetial
                                                                                                1. measured in KPA
                                                                                                  1. pure water has 0KPA
                                                                                                    1. highest water potential
                                                                                                      1. hypotonic
                                                                                                        1. high WP low solute concentration
                                                                                                        2. hypertonic
                                                                                                          1. low WP high solute concentration
                                                                                                          2. isotonic
                                                                                                            1. equal [otential
                                                                                                            2. turgid
                                                                                                              1. plant cell where cell membrane exerts pressure on the cell wall
                                                                                                              2. plasmolysed
                                                                                                                1. cell membrane shrunk away from cell wall
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