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Mind Map by sachakoeppen, updated more than 1 year ago
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Created by sachakoeppen
almost 9 years ago
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1.1 Life Processes - Movement of
Substances In and Out of Cells
- Chemical reactions enter and leave the cell in 3 ways
- Diffusion
- Active Transport
- Osmosis
- Diffusion
- Diffusion
- Diffusion happens when a substance is more
concentrated in one place than another (when you spray a can of deodorant)
- This difference in concentration is called a concentration gradient
- The particles move from an area of high concentration to an area of low concentration
- The particles move from an area of high concentration to an area of low concentration
- This difference in concentration is called a concentration gradient
- Factors affecting rate of diffusion
- Surface area to volume ratio
- If the volume of two cells is similar, the one with the biggest
surface area will have a larger surface area to volume ratio
- Therefore it will increase the rate of diffusion
- Therefore it will increase the rate of diffusion
- If the volume of two cells is similar, the one with the biggest
surface area will have a larger surface area to volume ratio
- Temperature
- At a higher temp the particles have more kinetic
energy and are moving around faster.
- Therefore in a given time more diffusion will occur
- Therefore in a given time more diffusion will occur
- At a higher temp the particles have more kinetic
energy and are moving around faster.
- Concentration Gradient
- When there is a big difference between the number of
particles in one place and another, diffusion will happen
much faster than if they are already quite spread out
- When there is a big difference between the number of
particles in one place and another, diffusion will happen
much faster than if they are already quite spread out
- Surface area to volume ratio
- Diffusion happens when a substance is more
concentrated in one place than another (when you spray a can of deodorant)
- Active Transport
- Sometimes a cell needs to take in a
substance against a concentration gradient
- This requires energy released from respiration, this is called active transport
- Particles move from an area of low concentration to an area of high concentration
- This requires energy released from respiration, this is called active transport
- Occurs in the roots of plants to move minerals into them against the
concentration gradient and also in the small intestine of animals
- Sometimes a cell needs to take in a
substance against a concentration gradient
- Osmosis
- Water molecules move from an area of high concentration to an area
of low concentration through the partially permeable membrane
- Partially permeable membrane has tiny holes (pores) through which very small molecules
(including water) can pass, but not larger molecules (such as sugar and proteins)
- Partially permeable membrane has tiny holes (pores) through which very small molecules
(including water) can pass, but not larger molecules (such as sugar and proteins)
- Water molecules move from an area of high concentration to an area
of low concentration through the partially permeable membrane
- Experiment to investigate surface area to volume ratio
- 3 different sized cubes of agar are prepared which
contain the indicator phenolphthalein.
- These are placed in hydrochloric acid which will diffuse into the cubes
- As it diffuses it will turn the indicator colourless
- As the size of the cube increases the surface area to volume decreases
- The smallest cube will be colourless, the middle cube will have a
but of pink in the middle and the largest cube will still be pink
- If these were real cells then the bigger cell wouldn't have received what it needs to all parts of the cell
- Therefore, it would need a bigger surface in order to rely on diffusion
- Therefore, it would need a bigger surface in order to rely on diffusion
- If these were real cells then the bigger cell wouldn't have received what it needs to all parts of the cell
- The smallest cube will be colourless, the middle cube will have a
but of pink in the middle and the largest cube will still be pink
- As the size of the cube increases the surface area to volume decreases
- As it diffuses it will turn the indicator colourless
- These are placed in hydrochloric acid which will diffuse into the cubes
- 3 different sized cubes of agar are prepared which
contain the indicator phenolphthalein.
- Surface Area
- As the rate of diffusion relies on the surface area, the parts of the
organisms that rely on diffusion tend to have a large surface area
- As the rate of diffusion relies on the surface area, the parts of the
organisms that rely on diffusion tend to have a large surface area
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