1
Q
Where do passive transport occur in living organisms? (4)
A
- gaseous exchange between alveolus & blood capillary [simple diffusion]
- reabsorption of water [osmosis] through the renal tubule in the kidney
- absorption of water [osmosis] by plant root hair cell
- absorption of fructose molecule in the villus [facilitated diffusion]
2
Q
Where do active transport occur in living organisms? (4)
A
- absorption of glucose & amino acids in the villus
- reabsorption of glucose through the renal tubule in the kidney
- transport of sucrose from leaf to phloem tissue
- absorption of mineral ions by a plant root hair cell
3
Q
State the effect of hypotonic solution on animal cells (RBC). (3)
A
- water diffuse into the cells by osmosis, cell swell & finally burst
- because plasma membrane is too thin to withstand the osmotic pressure built up in the cells
- RBC bursting aka haemolysis
4
Q
State the effects of hypertonic solution on animal cells (RBC). (3)
A
- water will move out of the RBC cells by osmosis
- cells shrink
- RBC undergoes crenation
5
Q
State the effect of isotonic solution on animal cells (RBC). (3)
A
- water diffuses in & out of the cell by osmosis at the same rate
- no net movement of water across the plasma membrane
- cells maintain normal shape
6
Q
State the effect of hypotonic solution on plant cells. (6)
A
- water diffuses into the vacuole by osmosis
- vacuoles expand & push the cytoplasm & plasma membrane against the cell wall
- cells are turgid
- cells do not burst because cell wall is rigid & strong
- turgor pressure gives support & maintains the shape of cell
- guard cells swell due to cell turgidity, stomata remains open for photosynthesis
7
Q
State the effect of hypertonic solution on plant cells. (5)
A
- water diffuses out of the vacuole by osmosis
- vacuole & cytoplasm shrink, plasma membrane pulled away from cell wall
- this process is known as plasmolysis which causes leaves & stems wilt
- plasmolysed plant cell can regain turgidity if placed in hypotonic solution immediately
- cells undergo deplasmolysis
8
Q
State the effects of isotonic solution on plant cells (3)
A
- when plant cell sap & extracellular solution are isotonic, water potential is the same
- movement of water diffusion in & out of cell is the same
- cells become flaccid
