Exchange of Materials (B3.1)
Diffusion, osmosis, active transport and exchange of materials in the gut and lungs
- Created by: Becky Marlton
- Created on: 13-03-13 18:39
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- Exchange of Materials (B3.1)
- Diffusion
- The net movement of particles from a high concentration to a low concentration
- Solute- solid
- Solvent- liquid
- The diffusion of water across a partially permeable membrane
- A partially permeable membrane allows water through it because it has tiny holes in it that only the small water molecules can fit through
- eg/ visking tubing
- A partially permeable membrane allows water through it because it has tiny holes in it that only the small water molecules can fit through
- exchange systems need to...
- ...have a large surface area so there is more space to diffuse on
- ...be moist because the molecules must be in the same state
- ...have a good blood supply because it keeps the concetration gradient steep
- ....have a small distance for the molecules to travel so it occurs quicker
- The net movement of particles from a high concentration to a low concentration
- Osmosis
- The diffusion of water across a partially permeable membrane
- A partially permeable membrane allows water through it because it has tiny holes in it that only the small water molecules can fit through
- eg/ visking tubing
- A partially permeable membrane allows water through it because it has tiny holes in it that only the small water molecules can fit through
- When there is a low concentration of water in the cell, water moves through osmosis across the partially permeable membrane and into the cell
- Water concentration must therefore me maintained as it could go the other way
- Isotonic- the water concentration both inside and outside the cells are the same
- Isotonic Sports drink contain the same amount of water, ions, and glucose as a healthy cell so it moves into the cell quicker without hurting it
- You should not drink them unless doing sport because...
- create stores of unused glucose as glycogen
- Pancreas will have to work twice as hard to maintain blood sugar levels
- Leads to diabetes
- You should not drink them unless doing sport because...
- Isotonic Sports drink contain the same amount of water, ions, and glucose as a healthy cell so it moves into the cell quicker without hurting it
- The diffusion of water across a partially permeable membrane
- Active Transport
- moving of substances against the concentration gradient. This requires energy from respiration
- Made in the mitochondria
- moving of substances against the concentration gradient. This requires energy from respiration
- Exchange in the gut
- Villi- finger like projections in the small intestines
- large surface area for more area for diffusion to occur on
- rich blood supply to keep the concentration gradient steep for efficient diffusion
- think wall (only 1 cell thick) so there is only a short distance for diffusion
- digestion
- Physical digestion- teeth, gut movement
- Chemical digestion- enzymes
- Villi- finger like projections in the small intestines
- Gas exchange in the lungs
- thorax- chest cavity
- diaphragm- muscle underneath the lungs which pulls down when breathing in
- Alveoli- balloon like adaption of the lungs in which diffusion occurs
- (1) air moves into the alveolus when breathing in
- (2) blood flows into the alveolus in cappilaries (low in oxygen)
- (3) oxygen diffuses from an area of high concentration(alveolus) to low concentration(blood)
- (4) blood rich in oxygen flows out of the alveolus and person breathes out
- in the same way carbon dioxide diffuses out of the blood
- (3) oxygen diffuses from an area of high concentration(alveolus) to low concentration(blood)
- (2) blood flows into the alveolus in cappilaries (low in oxygen)
- wall is only 1 cell thick so molecules have a small distance to travel
- (1) air moves into the alveolus when breathing in
- Rib cage- bones that protect the prgans in the chest such as the heart and lungs
- Intercostle muscles- relax and contract to increase and decrease pressure in the lungs
- this makes the air rush into the lungs for gas exchange- breathing in
- higher pressure (outside the body) to lower pressure (inside the lungs)
- this makes the air rush into the lungs for gas exchange- breathing in
- Diffusion
- Solute- solid
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