1.4 Diffusion

Question 1

How do glucose and oxygen for respiration move into the cell

Answer 1

By diffusion

Question 2

How do dissolved substances and gases move into and out of the cell

Answer 2

Diffusion

Question 3

How do waste products leave the cell

Answer 3

By diffusion

Question 4

Diffusion in detail

Answer 4

Diffusion is the spreading out of the particles of a gas, or of any substance in solution (a solute) this results in the net movement (overall movement) of particles.

The net movement is from an area of high concentration to an area of low concentration. It takes place because of random, movement of the particles. All the particles are moving and bumping into each other and this moves them all around.

Question 5

What speeds up diffusion

Answer 5

If there is a big difference in concentration between two areas, diffusion will take place quickly. Many particles will move randomly towards the area of low concentration. Only a few will move towards the area of high concentration.

However if there is a small difference concentration between the two areas the net movement will be quite slow.

The number of particles moving into the area of lower concentration by random movement will only be slightly bigger than the number of particles leaving the area.

Net movement = particles moving in - particles moving out

In general the greater the difference in concentration the faster the rate of diffusion this difference between the two areas of concentration is called the concentration gradient.

The bigger the difference the steeper the concentration gradient. The steeper the concentration gradient the faster diffusion takes place. Diffusion occurs down a concentration gradient.

Question 6

What affects the rate of diffusion

Answer 6

Temperature also affects the rate of diffusion an increase in temperature means the particles move more quickly. diffusion takes place more rapidly as the movement of particles speed up

Question 7

How do individual cells increase the rate of diffusion.

Answer 7

Increase the surface area of the cell membrane. Increasing the surface area means there is more room for diffusion to take place.

By folding up the membranes of the cell or the tissue lining of an organ. The area of which diffusion can take place is greatly increased.

Therefore the rate of diffusion is greatly increased. This means more of the substance is moved in a given time.

Question 8

What is the definition of diffusion

Answer 8

The net movement of particles from a area of high concentration to a area of low concentration