biology

Question 1

diffusion

Answer 1

net movement of particles down a concentration gradient from a region of higher concentration to a region of lower concentration

Question 2

factor affecting diffusion

Answer 2

1) steepness of concentration gradient
2) SA to V ratio
3) Temp
4) Particle size
5) thickness of membrane `

Question 3

explanation of diffusion process

Answer 3

XX has a lower concentration of … as compared to XX. Hence, there was a net movement of … from XX to XX down the concentration gradient.

Question 4

osmosis

Answer 4

XX region has a lower water potential as compared to XX. Hence there was a net movement of water molecules from XX to XX down the water potential gradient across a selectively permeable membrane.

Question 5

water potential of cytoplasm < surroundings (animal)

Answer 5

1) Surroundings have higher water potential than the cell cytoplasm
2) Hence there is net movement of water molecules into cytoplasm from the surroundings down the water potential gradient across a selectively permeable membrane
3) cell swells and lyses due to lack of cell wall.

Question 6

water potential of cytoplasm = surroundings (animal)

Answer 6

No net movement of water molecules, cell remains normal with no change in size or shape

Question 7

water potential of cytoplasm > surroundings (animal)

Answer 7

1) Cell cytoplasm has higher water potential than surroundings
2) Hence there is net movement of water molecules from the cytoplasm into the surroundings down the water potential gradient across a selectively permeable membrane
3) cell shrivels and crenation occurs
4) cell dehydrates and eventually dies

Question 8

water potential of cell sap in vacuole < surrounding

Answer 8

1) Surroundings have higher water potential than the cell sap in vacuole
2) Hence there is net movement of water molecules from surroundings into the cell sap down the water potential gradient across a selectively permeable membrane
3) vacuole increases in size and pushes cell content against cell wall
4) cell becomes turgid (but cell wall maintains shape, preventing cell from bursting

Question 9

water potential of cell sap in vacuole > surrounding (PLANT)

Answer 9

1) Surroundings have lower water potential than the cell sap in vacuole
2) Hence there is net movement of water molecules from cell sap to surroundings down the water potential gradient across a selectively permeable membrane.
3) vacuole decreases in size
4) cytoplasm and cell surface membrane shrink away from cell wall and cell plasmolyses