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Movement of Substances - Coggle Diagram

- - - - Affecting Factors of rate of diffusion
        
        Diffusion Distance
        
        Time taken for a substance to move from one point to another depends on the distance between the two points
        short dist= faster= higher rate
        longer dist= slower= lower rate
        
        Surface area-to-volume ratio
        
        The rate of movement of a substance across a cell membrane depends on how large the cell surface area of the cell is. For two cells with the same volume, the one with a larger surface area will have a higher rate of diffusion
        larger surface area= higher rate
        
        Calculations
        
        eg. for cube 1 by 1 by 1
        
        area of one face= 1x1= 1cm^2
        
        Surface area= number of faces (6) x area of one face
        6 x 1cm^2= 6cm^2
        
        Volume= 1 x 1 x 1= 1cm^3
        Answer: Surface area-to-volume ratio
        6cm^2 : 1cm^3
        
        Temperature (Chem)
        
        At higher temperatures, the particles possess greater kinetic energy. Thus, they are able to move faster, resulting in an increased rate of diffusion.
        
        Nature of solvent (optional)
        
        Mass of solute (optional)
        
        Concentration Gradient
        
        The steeper the concentration gradient for a substance, the faster the rate of diffusion for that substance
        
        Molecular mass (Chem)
        
        The larger the relative mass, the slower the rate of diffusion (the particles move slower).
        
        At a given temperature, heavier particles require more kinetic energy to move at the same speed as lighter particles.
- - - - Examples of Osmosis in plant cell (in a solution with higher water potential)
        
        There is a higher water potential in the solution than the cell sap in the vacuole.
        
        Thus, net movement of water molecules from the solution (region of higher water potential) into the plant cell (region of lower water potential) through a partially permeable membrane through osmosis.
        
        The cell expands or swells, becomes turgid (use term only for plant cell).
        
        As water molecules enter the cell, the vacuole increases in size and pushes the cytoplasm against the cell wall. The cell does not burst because it is protected by the inelastic cell wall. The turgidity of the cell with the water is called turgor. The pressure exerted by the water in the vacuole is the turgor pressure
        
        Turgor plays an important role in maintaining the shape of soft tissue in plants. The plants are able to remain firm and erect. This is because of the turgor pressure within their cells. When there is a high rate of water loss from the cells, they lose their turgidity and the plant wilts.
        E.g. Changes in the turgor of the guard cells cause the opening and closing of the stomata (guard cells have multiple vacuoles)
      - Examples of Osmosis in plant cell (in solution with lower water potential)
        1.There is a higher water potential in the cell sap in the vacuole than the solution
        
        Thus, net movement of water molecules leaves from the plant cell (region of higher water potential) into the surrounding solution (region of lower water potential) through a partially permeable membrane through osmosis.
        
        The cell decreases in size, becomes flaccid (use term only for plant cell).
        
        As water molecules leaves the cell, the vacuole decreases in size . The shrinkage of the cytoplasm and cell membrane away from the cell wall is called plasmolysis. The cell is said to be plasmolysed. A plasmolysed cell can be restored to its original state by placing it in water or in a solution with higher water potential.
        
        **Plasmolysis causes cells to become flaccid of limp. Cells will be killed if they remain plasmolysised for too long
    - - Example of Osmosis in animal red blood cell (solution with higher water potential)
        
        The solution has a higher water potential than the cytoplasm in the red blood cell.
        
        Thus, net movement of water molecules enters from the solution (region of higher water potential) into the red blood cell (region of lower water potential) through a partially permeable membrane via osmosis.
        
        Cell expands and bursts as red blood cell doesn't have a cell wall to prevent cell from bursting.
      - Example of Osmosis in animal red blood cell (solution with lower water potential)
        
        The cytoplasm in the red blood cell has a higher water potential than the surrounding solution.
        
        Thus, net movement of water molecules leaves from the red blood cell (region of higher water potential) into the surrounding solution (region of lower water potential) through a partially permeable membrane via osmosis.
        
        Cell shrinks and spikes appear on the cell (this is called crenation).
- - - - Diffusion
        
        Net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient.
        
        Energy from respiration not required
        
        Cell membrane not required
      - Active Transport
        
        Net movement of particles from a region of lower concentration to a region of higher concentration, against a concentration gradient
        
        Energy from respiration required
        
        Cell membrane required
    - - Examples of active transport in plant cells
        1.There is a lower concentration of minerals in the soil solution than in the cell sap of the root hair cell.
        
        Thus, minerals are absorbed from the soil (region of lower concentration) into the root hair cell (region of higher concentration) through the cell membrane via active transport.
        
        Active transport requires energy from respiration (ATP) because the ions are moved against the concentration gradient.