Biology

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  • Created by: Caitlin
  • Created on: 29-04-13 18:37
What is diffusion?
A passive process where particles move from an area of high concentration to an area of low concentration, along the concentration gradient.
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What is osmosis?
The passive movement of water particles through a partially permeable membrane from a low solute concentration to a high solute concentration .
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What is active transport?
The movement of substances from a low concentration to a high concentration, against the concentration gradient, requiring energy and carried out by protein carriers.
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What is a partially permeable membrane?
A membrane that only allows certain substances through depending on size.
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What does a cell membrane do?
Controls the passage ofsubstances in and out of the cell
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Why is energy needed in Active transport?
To change the shape of the protein carrier to move the ion.
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What are some exchange surfaces in humans?
Lungs, small intestine and kidney
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What structures does a cell need to be a good exchange surface?
1.Be well ventilated 2.Have a large surface area 3.Be thin 4.Have an efficient blood supply
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What are the functions of an exchange surface?
1.Maintain a concentration gradient. 2. Increase rate of diffusion. 3.Have a shorter distance for diffusion
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What happens in the alveoli?
Gas exchange takes place. Oxygen is transferred into the blood and CO2 out of the blood.
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What is breathing?
Process of muscles contracting and moving to change the size of the lungs
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What is ventilation?
The movement of air into and out of lungs
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What happens when you breath in?
1. Diaphram contracts and moves down 2. Ribs move outward 3.Thorax gets bigger 4.Volume of lungs increases 5. Lung pressure decreases 6. Air moves into lung
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What happens when you breath out?
1. Diaphram relaxes and moves up 2. Ribs move inwards 3.Thorax gets smaller 4.Volume of lungs decreases 5. Lung pressure increases 6. Air moves out of lung
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How are alveoli adapted?
1.One cell thick (thin) 2. Network of fine capillaries (High blood supply) 3.Moist (encouraging gas molecules to easily dissolve) 4. Large combined surface area (Large amounts of gasses can be exchanged.)
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What is transpiration?
Water movement in plants
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What is the vein in plants that water moves through?
Xylem
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What happens in transpiration? (3 steps)
Osmosis moves water from soil, through root hair cells, up xylem and into leaf. Evaporation moves water from calls to air space in spongy mesophyll layer. Diffusion moves water into the air.
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How does humidity affect rate of transpiration?
Water diffuses out of the leaf due to the high humidity in the air space in the spongy mesophyll layer and the low humidity in the air. If its humid outside then diffusion will be slower and transpiration will too.
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How does water move up the xylem?
By cohesion tension. Evaporating water causes water to move up xylem because all water molecules are bonded.
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How do plants reduce water loss?
1.waxy cuticle (ability to close stomata) 2.Few stomata 3.Small leaves 4.Stomata on bottom of leaf
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What is a potometer?
Measures the rate of transpiration
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What 4 things affect the rate of transpiration?
Light intensity, wind speed, temperature and humidity
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Other cards in this set

Card 2

Front

What is osmosis?

Back

The passive movement of water particles through a partially permeable membrane from a low solute concentration to a high solute concentration .

Card 3

Front

What is active transport?

Back

Preview of the front of card 3

Card 4

Front

What is a partially permeable membrane?

Back

Preview of the front of card 4

Card 5

Front

What does a cell membrane do?

Back

Preview of the front of card 5
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