Movement of Substances

Question 1

What 4 factors affect the movement of substances?

Answer 1

1. Surface Area to Volume Ratio
2. Distance
3. Temperature
4. Concentration Gradient

Question 2

How does a larger surface area to volume ratio affect the movement of substances?

Answer 2

The rate of diffusion, osmosis and active transport is higher in cells with a larger surface area to volume ratio. Substances move in and out of the cells faster.

Question 3

How does distance affect the movement of substances?

Answer 3

If substances only have a short distance to move, then they’ll move in and out of cells faster.

For example, cell membranes are very thin.

Question 4

How does temperature affect the movement of substances?

Answer 4

As the particles in a substance get warmer, they have more energy — so they move faster. This means as temperature increases, substances move in and out of cells faster.

Question 5

How does concentration gradient affect the movement of substances?

Answer 5

Substances move in and out of cells faster if there’s a big difference in concentration between the inside and outside of a cell.

If there are more particles on one side, there are more there to move across.

This only increases the rate of diffusion and osmosis though — concentration gradients don’t affect the rate of active transport. This is due to active transport moving against the concentration gradient.