Unit 2 - Movement of Substances

Question 1

Name the 3 types of movement of Substances

Answer 1

-Diffusion
-Osmosis
-Active Transport

Question 2

Define “Diffusion”

Answer 2

The net movement of particles within a gay or liquid down a concentration gradient until equilibrium is reached. This is a passive process as no energy is required.

Question 3

Name 4 factors which affect the rate of diffusion

Answer 3

-Concentration Gradient
-Diffusion Distance
-Surface Area : Volume Ratio
-Temperature

Question 4

Define “Osmosis”

Answer 4

The net movement of water molecules from a region of high water potential to a region of low water potential down a water potential gradient, through a partially permeable membrane. It is a passive process as no energy is required

Question 5

Define “Turgid”

Answer 5

cells are described as turgid when they are swollen and hard due to a high water content which has moved in via

Question 6

Define “Turgor pressure”

Answer 6

The pressure on the cell wall from the cell membrane pushing on it

Question 7

Define “Flaccid”

Answer 7

Occurs when water moves out of a cell via osmosis. The cell shrinks but the cell membrane does not peel away from the cell wall

Question 8

Define “Plasmolysis”

Answer 8

Occurs when there is too little water in a cell after too much water has moved out via osmosis. This will cause the cell membrane to peel away from the cell wall.

Question 9

Define “Active Transport”

Answer 9

The movement of molecules in to or out of a cell membrane against the concentration gradient using energy produces from cellular respiration making it an active process

Question 10

Why is Active Transport useful in organisms

Answer 10

Active Transport means that useful particles will continue to be absorbed even after equilibrium has been passed so the organism is able to maintain proper balance of useful particles and excrete waste products,