More About
Diffusion
Diffusion
is the movement of molecules from an area of higher concentration to an
area of lower concentration.
It is a passive process, which
means it happens naturally. An earthworm’s cells don’t say, “Hey,
I need some oxygen! I’m going to grab some.” The oxygen just
naturally passes through the cell membrane and into the cell, because
there is a higher amount of oxygen outside of the cell.
Water diffuses across a membrane,
too, just like small molecules. If the concentration of water is
higher inside of the cell, the water diffuses out across the
membrane. If the concentration of water is less inside of the
cell, water from the outside environment diffuses in. The
diffusion of water is known as osmosis.
Think about this question …
can you use diffusion to solve the chef’s challenge?
A chef at a new, busy restaurant is preparing
for the evening rush. He knows that his famous French fries will
be ordered by many people tonight. The chef doesn’t have the time
to cut all of the potatoes into bite-size fries each time someone
orders them – he has to have the fries cut in advance. How can he
keep the potato slices fresh until he needs to use them? He asks
the advice of his helpers, and they give him the following three
suggestions:
A) Cut
the potatoes, place in a
container and cover them with a lid
B) Cut the potatoes, place
in a container in fresh water
C) Cut
the potatoes, place in a
container in salt water
The chef was sick on the day his
biology teacher taught diffusion, and he can’t afford to try each
suggestion. Which method would keep his potato slices fresh?
Click on your
answer choice to find out whether or not you are correct!
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and Diffusion