Free movement of water molecules through a partially permeable membrane
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What is diffusion?
Free movement of molecules down a concentration gradient
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Diffusion involves the movement from...
a high concentration to a low concentration
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What is active transport?
Movement of molecules through a partially permeable membrane involving energy
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Osmosis involves the movement of water molecules from...
a high concentration to a low concentration
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Active transport involves the movement of substances from...
a low concentration to a high concentration
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What do the lungs exchange with the atmosphere?
Oxygen and Carbon Dioxide
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Why is oxygen needed?
For aerobic respiration
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Why is carbon dioxide exchanged?
It is a waste product of respiration
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What gives the lungs a large surface area?
Alveoli
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Give adaptations of alveoli
Thin walls, spherical shape for large surface area, moist lining, good blood supply
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Where does oxygen diffuse into?
Capillaries surrounding the alveoli
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Where does carbon dioxide diffuse into?
Back into the lungs
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What is in the thorax?
The lungs, ribs, heart, alveoli
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What is in the abdomen?
Everything below the diaphragm
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What increases the surface area in the small intestine?
Villi
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By what processes is digested food absorbed?
Diffusion and active transport
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Give adaptations of the villi
Rich blood supply for efficient diffusion, large surface area for diffusion, thin walls so short distance for diffusion
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Name features that gas exchange surfaces have in common
Large surface areas, gases are transported quickly to maintain a high concentration gradient, they are moist, they have thin membranes for easier diffusion
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Why does a high concentration gradient need to be maintained?
So diffusion is quicker
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Where does gas diffuse in and out of in plant leaf structures?
The stomata
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What is carbon dioxide needed for in plants?
Photosynthesis
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What substances are taken up by the roots?
Mineral ions and water
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What do roots have to increase their surface area?
Root hairs
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What is it called when water evaporates from the leaves?
Transpiration
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What is transpiration?
Transpiration is the loss of water vapour from the surface of plant leaves. It is more rapid in hot, dry, windy or bright conditions
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What happens if too much water is lost from a plant? Why does it do this?
It will wilt to protect themselves from further water loss. The leaves collapse and hang down, reducing surface area
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Why are stomata found on the lower surface of the leaf?
They are found on the underside so that it is protected from direct sunlight and energy and therefore reduces the time that they are open
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What is the transpiration stream?
The movement of water through a plant from the roots to the leaves as a result of the loss of water by evaporation from the surface of the leaves
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What are villi?
Finger like projections in the wall of the small intestine making it possible for all the digested food molecules to be transferred from the small intestine into your blood by diffusion and active transport.
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Why does food need to be broken down into small soluble molecules?
So diffusion across the gut lining can take place
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What are the two types of aids to breathing?
Iron lung(negative pressure) and Positive Pressure System
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Other cards in this set
Card 2
Front
What is diffusion?
Back
Free movement of molecules down a concentration gradient
Card 3
Front
Diffusion involves the movement from...
Back
Card 4
Front
What is active transport?
Back
Card 5
Front
Osmosis involves the movement of water molecules from...
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