First 269 words of the document:
19th January 2010
Diffusion is the net movement of particles from a high concentration to a low one.
Once equilibrium is reached, the particles stop moving. Equilibrium is when the
particles have the same concentration in all marks.
What happens in the tube?
In the tube, the liquid particles turn to vapour, gas particles will diffuse within the
air, and the paper will turn blue in stages.
How is active transport different?
In active transport, the particles move against the concentration gradient. To do
this, energy is used for respiration respiration occurs in the mitochondria. ATP
is a molecule that stores energy in cells until it is needed.
1 molecule of glucose 38 molecules of ATP
Examples of Active Transport
In the plant, there is a higher concentration of mineral ions and a low
concentration in the soil. Mineral ions move against the concentration gradient
and move from the soil, into the plant.
4a. Cyanide is such an effective poison because it shuts down the mitochondria
from producing ATP. ATP is used in vital systems such as the nervous system.
Active transport stops because the energy supplies dry up.
4b. Active transport is vital for sea animals because their kidneys cannot get rid
of all the salt they intake. Through the salt glands, salt is removed from the body.
The salt travels from the low concentration of the body to the high concentration
of the surrounding sea.