Diffusion

Question 1

Defination of diffusion

Answer 1

The net movement of molecules or ions from an region of high concentration to an region of low concentration down an diffusion gradient until dynamic equilibrium is reached.

Question 2

How is dynamic equilibrium reached

Answer 2

• all particles are constantly moving due to kinetic energy
• this motion is random
• they constantly bump into each other and the sides of the container they are in and will eventually distribute themselves evenly

Question 3

What is diffusion

Answer 3

Passive and cross a fully permeable membrane

Question 4

What happen to the rate of diffusion if temperature is increased

Answer 4

Increased temp increases kinetic energy of molecules and will therefor will increase rate of diffusion

Question 5

What happens to diffusion if surface are is increased

Answer 5

Greater surface area over which diffusion occurs the faster the rate of diffusion

Question 6

What happens to the rate of diffusion if the molecules are small

Answer 6

Small molecules can pass through pores more easily than larger molecules

Question 7

Why is facilitated diffusion used

Answer 7

Helps charge ions and polar molecules pass through the membrane.

Question 8

How do channel proteins help with facilities diffusion

Answer 8

• form water filled hydrophilic channel across membrane
• Allows specific water soluble ions to pass through
• selective so can only open up in presence of specific ion
• binding of specific ions changes the shape of protein allowing ions to pass

Question 9

How to carrier proteins help with facilitated diffusion

Answer 9

• a molecule with a specific complementary shape binds with the carrier protein
• causes protein to change shape
• molecules are realised o the other side of the membrane