Molecules Move Across Membranes

Question 0

Definition of osmosis?

Answer 0

Movement of water molecules from an area of high concentration to low concentration across a semi permeable membrane

Question 1

Defenition of diffusion?

Answer 1

Particles moving from a high concentration to a low concentration

Question 2

What is a turgid cell?

Answer 2

Water enters the cell down the water potential gradient, sap vacuole fills with water, cell membrane pushes on cell wall as more water enters, pressure from wall prevents further expansion, cell is TURGID

Question 3

Diffusion: how does temperature effect the rate of diffusion?

Answer 3

At higher temps, molecules have more kinetic energy so move faster. Diffusion will occur faster.

Question 4

Diffusion: how does concentration gradient effect the rate of diffusion?

Answer 4

If there is a large difference between 2 surface areas, it will diffuse quicker, if it is smaller it will be slower.

Question 5

Diffusion: how does surface area effect the rate of diffusion?

Answer 5

Larger surface area will speed up the rate of diffusion Eg, alveoli in lungs are v. Large

Question 6

Diffusion: how does volume effect the rate of diffusion?

Answer 6

Takes longer if it has to fill a larger volume.

Question 7

Describe the experiment for osmosis in a non living tissue.

Answer 7

Fill Visking tubing with sucrose solution 1/2. Tie both ends, record mass of content. Place tubing in deionised water, remove and blot tubing, record mass.