B1- Transport in cells
- Created by: liv.moz
- Created on: 18-04-22 16:18
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- B1- Transport in cells
- Diffusion
- Spreading out of particles or a gas or in a solution.
- Net movement of particles from a region of high concentration to low concentration.
- Movement of particles is random
- Net movement of particles from a region of high concentration to low concentration.
- Can occur quickly in water but must be hot as hot water particles have more energy than cold water particles.
- Substances that can diffuse across a cell membrane are: glucose, water, amino acids and oxygen.
- Factors that affect rate of diffusion
- Temperature, concentration gradient and surface area
- Concentration gradient- larger CG= faster diffusion
- Temperature- Higher temp. give particles more energy and increase rate of diffusion
- Surface area- lager surface area= faster diffusion
- Temperature, concentration gradient and surface area
- Surface area to volume ratio
- The surface area defines how quickly organisms can absorb substances
- Exchange Surface
- Alveoli: They are very thin, are moist, have large combines surface area, and covered by a network of fine capillaries.
- Villi: Theyt are very thin, have a large combined surface are and are covered by lots of caplillaries.
- Alveoli: They are very thin, are moist, have large combines surface area, and covered by a network of fine capillaries.
- Spreading out of particles or a gas or in a solution.
- Osmosis
- Special type of diffusion, where water moves from an area of high water concentration to low water concentration through a PARTIALLY PERMEABLE MEMBRANE.
- Therefore it moves from a dilute solution to a concentrated solution.
- Dilute- Contains high concentration of water and low concentration of sugar.
- Water- SOLVENT
- Sugar- SOLUTE
- Concentrated- contains low concentration of water and high concentration of sugar.
- Dilute- Contains high concentration of water and low concentration of sugar.
- Therefore it moves from a dilute solution to a concentrated solution.
- ISOTONIC- If trhe concentration of solute outside the cell is the same as the internal concentration.
- HYPERTONIC- If the concentration of solute outside the cell is higher than internal concentration.
- HYPOTONIC- If concentration of solute outside the cell is lower than the internal concentration.
- Special type of diffusion, where water moves from an area of high water concentration to low water concentration through a PARTIALLY PERMEABLE MEMBRANE.
- Active Transport
- Movement of dissolved molecules into or out of the cell through a cell membrane, from a region of low concentraion to a region of higher concentration
- Involves the movement of substances
- Occurs in digestion, lots of sugar already in blood and very little in gut so sugar is moved up a concentration gradient into the blood.
- Differences between transport in cells
- Diffusion and osmosis occur down a concentration gradient (High to low)
- Active transport occurs up a concentration gradient (low to high)
- Diffusion spreads its particles around an area.
- Osmosis is specifically about water.
- Osmosis occurs through partially permeable membrane, diffusion occurs anywhere
- Diffusion and osmosis occur down a concentration gradient (High to low)
- Diffusion
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