Biology 2

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  • Created by: kelz0209
  • Created on: 13-04-14 16:28
In terms of osmosis, explain what will if an animal cell is placed in a concentrated sugar solution.
Water will move out of the animal cell by osmosis from an area of high water concentration to an area of low water concentration.
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Explain what is meant by a partially permeable membrane.
A partially permeable membrane only allows small molecules (e.g. water) to diffuse through it.
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Other than osmosis, by what two processes do substances move across exchange surfaces?
Diffusion and active transport.
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Give four ways in which exchange surfaces in animals are adapted to maximise their effectiveness.
They're thin, they have a large surface area, they have lots of blood vessels and they're often ventilated.
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Describe what happens when you breathe out.
The intercostal muscles and diaphragm relax. The volume of the thorax decreases. This increases the pressure, so air is forced out.
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What name is given to the air sacs in the lungs where gas exchange happens?
Alveoli.
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Our lungs allow us to breathe in and out. Describe the changes that take place in the thorax when breathing air into the lungs.
The diaphragm contracts, and the intercostal muscles contract. This increases the volume of the thorax, and so decreases the pressure in the thorax, drawing air in.
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Some people can't breathe on their own and have to use an artificial ventilator. How does an artificial ventilator work?
They work by pumping air into lungs, which expands theribcage. When they stop pumping, the ribcage relaxes and pushes air back out of the lungs.
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Give one potential disadvantage of using an artificial ventilator.
They can cause damage to the lungs.
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Four 5cm long cylinders were cut from a fresh potato.They were then placed in different sugar solutions.After four hours the potato cylinders were removed and measured.Which potato cylinder would you expect to be the shortest? Explain why.
The potato cylinder in tube D- tube contains the most concentrated sugar solution so this cylinder will have lost the most water by osmosis.
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The potato cylinder in tube A increased in length during the four hours. Explain why this happened.
Tube A contained still water- some of water moved by osmosis into the potato cylinder from an area of high water concentration to an area of low water concentration.
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Other cards in this set

Card 2

Front

Explain what is meant by a partially permeable membrane.

Back

A partially permeable membrane only allows small molecules (e.g. water) to diffuse through it.

Card 3

Front

Other than osmosis, by what two processes do substances move across exchange surfaces?

Back

Preview of the front of card 3

Card 4

Front

Give four ways in which exchange surfaces in animals are adapted to maximise their effectiveness.

Back

Preview of the front of card 4

Card 5

Front

Describe what happens when you breathe out.

Back

Preview of the front of card 5
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