A freshly obtained dandelion stem measuring 5cm long was split lengthwise to obtain two similar pieces. The pieces were placed in solutions of different concentrations in petri dishes (L1 and L2) for 20 minutes. The appearance after 20 minutes is as shown
(a) Account for the appearance of the pieces in solution L1 and L2
(b) State the significance of the biological process involved in the experiment.
Answer:
a)
- L1 solution is hypotonic to the cytoplasm of the cells.
Inner cells or cortical cells lack cuticle, gained water by osmosis and become turgid hence increased in length. Epidermal cells did not gain water because they are covered by a water proof cuticle leading to curvature.
- L2 solution is hypertonic compared to the cytoplasm of the cells of the tissue. Inner cells lost water by osmosis, become flaccid and decreased in length. Epidermal cells did not lose water due to waterproof cuticle leading to curvature.
b)
- Support in herbaceous plants when cells are turgid.
- Absorption of water by root hair cell.
- Opening and closing of stomata.
- L1 solution is hypotonic to the cytoplasm of the cells.
Inner cells or cortical cells lack cuticle, gained water by osmosis and become turgid hence increased in length. Epidermal cells did not gain water because they are covered by a water proof cuticle leading to curvature.
- L2 solution is hypertonic compared to the cytoplasm of the cells of the tissue. Inner cells lost water by osmosis, become flaccid and decreased in length. Epidermal cells did not lose water due to waterproof cuticle leading to curvature.
b)
- Support in herbaceous plants when cells are turgid.
- Absorption of water by root hair cell.
- Opening and closing of stomata.
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Explain what would happen to red blood cells if they are placed in a concentrated salt solution. 
