Q7 of 67 Page 48

Study the diagram given below and answer the questions that follow:


(a) Name the process being studied in the above experiment.


(b) Explain the process mentioned in (a) above.


(c) Why is oil placed over water?


(d) What do we observe with regard to the level of water when this set up is placed in (1) bright sunlight (2) humid conditions (3) windy day?


(e) Mention any three adaptations found in plants to foster the process mentioned in (a) above.

(a) The process being studied in the above experiment is transpiration of water.


(b) Transpiration is defined as the loss of water through evaporation from the aerial parts (stem and leaves) of the plant.


(c) A layer of oil is placed over the water to ensure that no loss of water takes place through direct evaporation from the water present in the test tube.


(d) When the experimental setup is placed in


1. Bright sunlight: In bright sunlight, the rate of transpiration highly increases thus the level of the water level in the test tube is seen to decrease fast from its initial marking.


2. Humid conditions: In humid condition, the rate of transpiration is reduced and thus level of water in the test tube decreases from its initial mark, but at a very slow rate.


3. Windy day: On a windy day the rate of transpiration highly increases thus the level of the water level in the test tube is seen to decrease fast from its initial marking.


(e) To foster the process of transpiration the three adaptations found in plants are:


i. Narrow leaves to reduce the surface area for transpiration.


ii. Loss of leaves, that is, leaves are completely absent or changed into spines, such as in cacti.


iii. Presence of a thick cuticular (wax) layer present on the surface of the leaves.


More from this chapter

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4

The diagram below represents a layer of epidermal cells showing a fully grown root hair.

Study the diagram and answer the questions that follow:



(b) The root hair cell is in a turgid state. Name and explain the process that caused this state.


(c) Mention one distinct difference between the parts labeled A and B.


(d) Draw a diagram of the above root hair cell as it would appear when a concentrated solution of fertilizers is added near it.

 5

Two potato cubes each 1 cm3 in size, were placed separately in two containers (A & B), the container (A) having water and the other (B) containing concentrated sugar solution. After 24 hours when the cubes were examined, those placed in water were found to be firm and had increased slightly in size and those placed in concentrated sugar solution were found to be soft and had somewhat decreased in size. Use the above information to answer the questions that follow:

(a) Account for the firmness and increase in the size of the potato cubes placed in water.


(b) Account for the softness and decrease in size of the potato cubes which were placed in sugar solution.


(c) Name and define the physical process being investigated in this experiment.

 6

Given below is the diagrammatic representation of the transverse section of a part of a plant. Study it and answer the questions that follow:


(a) Name the part of the plant that is shown.


(b) Label the parts 1 to 6.


(c) Write the functions of parts 3 and 5.

 8

Show by a series of diagram, the change which a plant cell will undergo when placed in

(a) Hypertonic salt solution and


(b) Hypotonic salt solution.