Diffusion, Osmosis and Active Transport

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  • Created by: lh1002
  • Created on: 18-06-16 16:42
What is diffusion?
The net movement of particles from an area of high concentration to low concentration.
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What kind of process is diffusion?
A passive process- no energy is required.
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To maximize the rate of diffusion, what would you expect?
A large surface area, a high concentration gradient, short distance to travel, thin walls to pass through.
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What is a concentration gradient?
A difference in concentration between two areas next to each other.
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What is osmosis?
A special type of diffusion where water diffuses from an area of high water molecules to low water molecules through a partially permeable membrane.
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What happens if animal cells absorb too much water?
They will swell and as they have no cell wall, eventually will burst.
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What is active transport?
When dissolved molecules move across a cell membrane from a lower to a higher concentration-against the concentration gradient - and therefore require energy
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What is a hypertonic solution?
The solution has a higher solute concentration than the cell so water moves out of the cell and into the solution causing the cell to plasmolyse (when the cell membrane and cytoplasm pulls away from the wall)
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What is a hypotonic solution?
The solution has a lower solute concentration than the cell so water moves into the cell causing plant cells to swell and become turgid and animal cells to swell and burst
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What is an isotonic solution?
The concentration of solutes is equal inside and outside the cell so water moves across the membrane in both directions maintaining cell size
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What do cell membranes allow to diffuse?
Small particles such as oxygen, amino acids, glucose and water but prevent larger starches and proteins from getting in.
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Why is active transport needed?
In the digestive system, there is sometimes a low concentration of nutrients in the gut, but high in the blood and because the organism needs these molecules, they still have to be absorbed so this is where active transport is needed.
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Other cards in this set

Card 2

Front

What kind of process is diffusion?

Back

A passive process- no energy is required.

Card 3

Front

To maximize the rate of diffusion, what would you expect?

Back

Preview of the front of card 3

Card 4

Front

What is a concentration gradient?

Back

Preview of the front of card 4

Card 5

Front

What is osmosis?

Back

Preview of the front of card 5
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