Phototropism is a type of tropism response. Diagram 1.1 shows another type of tropism response of a plant.
(a) Based on Diagram 1.1,
(i) state the type of response [1 mark]
(ii) state the stimulus for the response. [1 mark]
(b) Explain how the tropism response at the shoot help on plant’s survival. [2 marks]
(c) The following statement is about nastic tropism.
Nastic tropism is a response that is quicker and more apparent compared to tropism response.
(i) State one type of nastic response. [1 mark]
(ii) Diagram 1.2 shows the response of a plant when it is touched.
Give one benefit of this type of response to the plant. [1 mark]
Answer:
(a)(i) Thigmotropism
(a)(ii) Touch
(b)
1: To obtain support
2: Shoots grow towards light // Shoots show positive phototropism
3: To carry out photosynthesis
Any two answers
(c)(i) Photonasti // Seismonasti // Niktinasti // Thermomonasti // Tigmonasti
(c)(ii) For survival // protection
Diagram 2.1 shows process X that occurs when a plant cell is immersed in distilled water.
(a)(i) State the name of process X. [1 mark]
(ii) Complete Diagram 2.2 by drawing the condition of the vacuole after being immersed in distilled water for 30 minutes.
[1 mark]
(b) Diagram 2.3 shows the conditions of an animal cell being immersed in 10% sodium chloride solution.
Explain how this condition occurs. [2 marks]
(c) A climber was found in a very weak condition due to dehydration after getting lost for a few days. She was treated with saline solution.
Explain why the treatment is given. [2 marks]
Answer:
(a)(i) Osmosis
(a)(ii)
1: Drawing line of the vacuole must be connected
2: Vacuole size is larger
(b)
1: 10% sodium chloride solution is hypertonic solution to the cells
2: Water diffuses out of the cell by osmosis
3: Cell size decreases // Cell shrinks // Crenation occursÂ
Any two answers
(c)
1: Saline solution is an isotonic solution to blood plasma
2: Contains 0.85g – 0.90g sodium chloride per 100 ml
3: Recovers loss of water // Rehydration
Any two answers