Osmosis

Question 1

Osmosis

Answer 1

Is the net movement of water molecules from a region of high water potential to one of low water potential, down the concentration gradient through a partially permeable membrane.

It is passive movement as it doesn’t require kinetic energy.

Question 2

Uses of osmosis

Answer 2

Absorption of water by root hair cells to all plant cells.
Absorption of water by small intestine to blood in animals.

Question 3

Osmosis in plant cells: Diluted/hypotonic solution

Answer 3

Water moves from outside to inside the cell through osmosis. Vacuole and cytoplasm swell, causing cell to become turgid (supports cell). Cell wall prevents from bursting.

Question 4

Osmosis in plant cells: Concentrated/hypertonic solution

Answer 4

Movement of water from inside to outside the cell by osmosis. Cytoplasm and vacuole shrink, and cell is flaccid. Plant begins wilting. This stage is reversible.

Question 5

Osmosis in plant cells: Highly concentrated/hypertonic solution

Answer 5

Movement of water from inside to outside the cell by osmosis. Cytoplasm and vacuole shrink more & membrane and cytoplasm move away from wall. Cell becomes plasmolysed. This stage is irreversible.

Question 6

Osmosis in animal cells: hypotonic solutions

Answer 6

Water moves from outside to inside cell by osmosis. Cell swells, and may burst due to pressure. Cell becomes lysed.

Question 7

Osmosis in plant/animal cells: isotonic solutions

Answer 7

Equal water potential inside and outside cells, so no change occurs.

Question 8

Osmosis in animal cells: hypertonic solutions

Answer 8

Water moves from inside to outside the cell through osmosis. Cell becomes wrinkled and shrinks.