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B1

Terms in this set (11)

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The ___________ an organism is the _________ its surface area is compare to its volume
larger, smaller
In _________-celled organisms, gases and dissolved substances can diffuse _________ _____ the cell across the ____ ________. This is because they have a _______ surface area compared to their volume, so ________ _________ can be exchanged across the membrane to supply the _______ of the cell.
single, directly, into, cell membrane, large, enough, substance, volume
___________ organisms have a _________ surface area compared to their volume- _______ _______ substances can diffuse from their outside to supply their entire volume. This means they need an __________ _______ for efficient diffusion. These allow __________ of the necessary substances to pass through.
multicellular, smaller, not enough, exchange surface, enough
Exchange surfaces are _____________ to maximise ________
-They have a ______ ________ so substances only have a _____ distance to ________
- They have a ______ surface area so ______ of substance can _____ at once
- Exchange surfaces in ________ have ________ of blood vessels, to get stuff in and out of the blood _________
- _______ exchange surfaces in animals (e.g.______) are often __________ too- air moves in and out
Adapted, effectiveness, thin membrane, short, diffuse, large, lots, diffuse,animals, lots, quickly, gas, alveoli, ventilated
Osmosis experiment
1- cut a potato into __________ cylinders and get some beakers with _________ _________ ___________ in them. One should be ______ _____ and the other should be a ________ _________ sugar solution. (e.g. ___ mol/dm^3). You can have few different concentrations in between e.g. (0.2, 0.4)
2- You measure the ________ of the cylinders, then leave one in each cylinder for about ____ ________
3- Take them out and ______ try them with a __________ _______ and measure their masses again
4- If the cylinders have drawn in water by osmosis, they'll have ______________ in mass. If water has been drawn out they'll have __________ in mass. You can calculate the ____________ change in mass and _______ some ________
5- The __________ variable is the ______ ________ and the independent variable is the ________ of the sugar solution
6- You need to be aware what _________ may arise. If the potato cylinders are not ________ _____ the excess water could give a ______ ____ or if water ____________ from the beakers, the _____________ of the sugar solutions would change. You can _________ the effect of these errors by ___________ the experiment and calculating __________ _________ __________ at each concentration.
identical, different, sugar, solutions, pure, water, very concentrated, 1, mass, 24, hours, dry, paper, towel, increased, decreased, percentage, plot, graphs, dependant, chip, mass, concentration, errors, fully, dry, higher, mass, evaporated, concentration, reduce, repeating, mean, percentage, change
Osmosis experiment
By calculating the ___________ __________, you can _________ the _________ of ________ concentration on the cylinders that ______have the same ________ mass. An _________ in mass will give a positive percentage change and a decrease will give a __________ percentage change
percentage change, compare, effect, sugar, didn't, initial, increase, negative
Diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
The ________ the _________ _________ the faster the diffusion rate
A ________ ________ will also give a faster diffusion rate because the particles have more energy, so move around faster
bigger, concentration, gradient, higher temperature
Osmosis
The movement of water across a partially permeable membrane from an area of higher concentration to an area of lower concentration.
active transport
the movement of dissolved molecules into or out of a cell through the cell membrane, from a region of lower concentration to a region of higher concentration. The particles move against the concentration gradient , using energy released during respiration.
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