substance move in and out of cells across cell membranes via..
diffusion
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diffusion is ....
the spreading out of particles of any substance is solutions or particles of gas, resulting in a net movement from an area of higher concentration to an area of lower concentration
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oxygen and carbon dioxide are...
transported in and out of cells by diffusion in gas exchange
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the waste product urea is....
transported by diffusion into the blood plasma for excretion in the kidney
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give the different factors that affect rate of diffusion
1. difference in concentrations, 2. temperature, 3. surface area of membrane
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what has a relatively large surface area to volume ratio and what does that allow..
a single celled organism. it allows sufficient transport of molecules into and out of the cell to meet the needs of the organism
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in multicellular organisms, surfaces and organ systems are specialised for...
exchanging materials. this is to allow sufficient molecules to be transported into and out of cells for the organisms needs.
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what is the effectiveness of an exchange surface increased by
having a large surface are, a thin membrane to provide short diffusion path, having an efficient blood supply in animals, and being ventilated for gas exchange in animals.
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the bigger the concentration gradient the faster it will happen
correct
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the higher the temperature...
the faster the particles are moving due to more kinetic energy
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the higher the temperature the greater the rate of diffusion
correct
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calculating surface area to volume ratio
you find surface area ( area of each square or shape and times by how many faces there are) and add it to the volume
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as organisms get larger, the surface area to volume ratio....
falls sharply
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does this create a huge problem for multicellular organisms
yes. their surface area is not large enough for their volume
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why isnt this a problem for animals
because animals have a large surface area for gas exchange e.g lungs of mammals . secondly animals have a transport system to carry gases around the body.
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fish get their oxygen from ...
water. it then flows over gills where oxygen is transported into bloodstream
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describe the gills
covered in fine filaments where the gases pass in and out of blood
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what passes into the filament..
deoxygenated blood
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what happens next
oxygen diffuses from water into the blood. oxygenated blood returns to the body.
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give the three adaptations of the filament to make diffusion efficient
the filaments provide a massive surface area for the gills , they also have a thin membrane to provide short diffusion path and they also have an efficient blood supply to take oxygenated blood away.
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what does taking the oxygenated blood away do..
ensures that the concentration gradient is always high
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Other cards in this set
Card 2
Front
diffusion is ....
Back
the spreading out of particles of any substance is solutions or particles of gas, resulting in a net movement from an area of higher concentration to an area of lower concentration
Card 3
Front
oxygen and carbon dioxide are...
Back
Card 4
Front
the waste product urea is....
Back
Card 5
Front
give the different factors that affect rate of diffusion
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