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meaning of diffusion
net movement of molecules from an area of higher concentration to an area of lower concentration
what type of molecules can diffuse
small molecules such as oxygen, glucose, amino acids and water
meaning of osmosis
net movement of water molecules across a partially permeable membrane, from a region of higher water concentration to a lower water concentration
meaning of active transport
movement of particles from an area of lower concentration to an area of higher concentration
why is it called active transport
it requires energy from respiration as it is working against the gradient
describe the practical; investigating osmosis in potatoes
place different sucrose solutions including 0% for a control in different boiling tubes
dry potato strips on paper towel and measure masses
place each potato strips into each sucrose solution for 20 minutes and record the change in mass
repeat each solution several times with potato with similar masses
3 factors that affect rate of movement
concentration gradient
temperature
Surface Area : Volume ratio
how does the concentration gradient affect the rate of movement
the greater the difference in concentration, the faster the rate of diffusion an more particles are randomly moving down the gradient that against it
how does the temperature affect the rate of movement
the greater the temperature the movement of particles, resulting in more collisions
how does the Surface Area : Volume ratio affect the rate of movement
the greater the surface area the more space for particles to move through - faster diffusion rate
Note 
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