Exchange of materials: diffusion/osmosis/active transport

Question 1

What is osmosis?

Answer 1

the movement of water across a SELECTIVELY PERMEABLE membrane from a dilute solution to a more concentrated solution

Question 2

how often does the movement of water occur?

Answer 2

it is a random motion requiring no energy from the cells

Question 3

what fluid surrounds cells?

Answer 3

tissue fluid

Question 4

What happens if the tissue fluid is more dilute than the cells?

Answer 4

water moves into cells by osmosis - cells swell and burst

Question 5

What happens if the tissue fluid is more concentrated than the cells?

Answer 5

water moves out the cells by osmosis - cells shrivel up (shrink) so no longer survives

Question 6

what happens when a plant gains water by osmosis?

Answer 6

vacuole swells- structure is rigid - cells are turgid

Question 7

what happens when a plant loses water by osmosis?

Answer 7

structure weakened - cells are flaccid

Question 8

What is active transport?

Answer 8

cells move substances against concentration gradient acorss selectively permeable membrane using energy from respiration

Question 9

how does active transport work?

Answer 9

• transport protein carries useful molecule
• rotates and releases it inside cell
• then rotates back to original position

Question 10

What is diffusion?

Answer 10

movement of molecules from a high to low concentration across a selectively permeable membrane

Question 11

How do you increase rate of diffusion?`

Answer 11

• increase surface area
• decrease distance to diffuse
• larger concentration gradient
• increase temperature