Diffusion

Question 1

What is diffusion?

Answer 1

• The movement of particles of substances by kinetic energy from regions of their own higher concentration to regions of their own lower concentration until their distribution is even.

Question 2

What is net diffusion?

Answer 2

• The resultant of the movements in all directions.

Question 3

What happens in a confined space to the particles?

Answer 3

• A dynamic equilibrium results in which the number of moving per second in each direction is the same.

Question 4

What are the factors that affect the rate of diffusion?

Answer 4

• Temperature
• Surface Area
• Concentration Gradient
• Distance

Question 5

How does temperature affect the rate of diffusion?

Answer 5

• Raising the temperature gives the molecules more kinetic energy, and thus they spread out from the area of high concentration at a faster rate.

Question 6

How does surface area affect the rate of diffusion?

Answer 6

• Larger surface area separating two regions results in a faster rate of diffusion.

Question 7

How does the concentration gradient affect the rate of diffusion?

Answer 7

• The greater the difference in concentration between two areas, the faster the rate of diffusion.

Question 8

How does distance affect the rate of diffusion?

Answer 8

• Distance separating the two areas – “short diffusion path”. The shorter the distance, the faster the rate of diffusion.

Question 9

What is osmosis?

Answer 9

• The net diffusion of water across a partially permeable membrane

Question 10

What is water potential?

Answer 10

• The tendency for the system to donate water to its surroundings

Question 11

How does the cellulose cell wall help the plant cell?

Answer 11

• It prevents the cell from bursting if it takes up water from its surroundings by osmosis.
• The cell volume increases as water enters and the cell membrane is stretched, but the cell wall stops the cell membrane from rupturing.

Question 12

What happens if a plant cell is placed in distilled water?

Answer 12

• It will swell up due to water uptake by osmosis.
• The wall will push back on the cell resisting further water uptake, resulting in the cell and the distilled water having the same water potential.
• The cell is now fully turgid.

Question 13

What happens if a plant cell is placed in sucrose solution,

Answer 13

• Cell will lose water by osmosis to the sucrose solution.
• Cell membrane will come away from the wall, leaving the cell plasmolyzed.