Bio C3

Question 1

1.Define diffusion

Answer 1

The net movement of molecules from an area of high concentration to an area of low concentration down their concentration gradient

Question 2

2.Where does the energy for the movement of particles in diffusion come from?

Answer 2

From the kinetic energy of the particles that causes them to move in random directions

Question 3

3. How does temperature affect the rate of diffusion?

Answer 3

As the temperature increases, so does the rate of diffusion as the particles have more kinetic energy and move faster

Question 4

4. How does the concentration gradient affect the rate of diffusion?

Answer 4

The greater the concentration gradient (the difference between the two areas), the faster the rate of diffusion

Question 5

5. How does the surface area of the membrane affect the rate of diffusion?

Answer 5

As the surface area increases so does the rate of diffusion as there is more space for the particles to move through

Question 6

6. How does the diffusion distance affect the diffusion rate?

Answer 6

The shorter the distance, the faster the rate of diffusion

Question 7

7. What is osmosis?

Answer 7

The net movement of water molecules from a high water potential to a low water, potential down their water potential gradient across a partially permeable membrane

Question 8

8. What’re the possible results of an animal cell in a solution?

Answer 8

In pure water: There is a net movement of water into the cell which causes the animal cell to burst
In concentrated solution: There is a net movement of water out of the cell which causes the animal cell to shrink

Question 9

9. What’re the possible results of a plant cell in a solution?

Answer 9

In pure water: There is a net movement of water into the cell which causes the plant cell to become turgid (it does not burst because of the strong cell wall)
In concentrated solution : There is a net movement of water out of the cell which causes the plant cell to become plasmolysed (the cell membrane peels away from the cell wall)

Question 10

10. How is a plant cell supported?

Answer 10

The water creates turgor pressure which pushes the cell membrane against the inelastic cell wall

Question 11

11. Define active transport, give examples from humans and plants

Answer 11

Uptake of minerals and nutrients in the small intestine
Uptake of minerals into root hair cells

Question 12

12. Explain how active transport involves proteins

Answer 12

Carrier proteins move substances from one side of the membrane to the other using energy against concentration gradient