Q2 of 67 Page 48

A leaf cell of a water plant was placed in a liquid other than pond water. After some time, it assumed a shape as shown below:


(a) Give the term for the state of the cell it has acquired.


(b) Comment on the nature (tonicity) of the liquid surrounding the cell.


(c) Redraw in the space provided, the diagram of the cell if it is soon placed in ordinary water for some time.

(a) The term for the state of the cell it has acquired in the given diagram is plasmolyzed.

A plasmolyzed cell is the cell whose cell content has shrunken from its cell wall (in case of plant cells as shown in the diagram) due to exosmosis of water.


(b) Plasmolysis is the result of exosmosis of water thus; the tonicity of the liquid surrounding the cell is hypertonic.


A hypertonic solution is a solution surrounding the cell which has a higher solute concentration than the concentration of solutes inside the cell. Consequently, the water molecules from the interior of the cell will move out leading to the plasmolysis of the cell.


(c) If this plasmolysed cell is soon placed in ordinary water it will regain its turgidity and will be deplasmolysed.



More from this chapter

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6

What is transpiration pull? How is it caused?

 1

The following diagram represents a plant cell after being placed in a strong sugar solution.


Guidelines 1 to 5 indicate the following:


(1) Cell Wall


(2) Strong Sugar Solution


(3) Protoplasm


(4) Large vacuole


(5) Nucleus


(a) What is the state of the cell shown in the diagram?


(b) Name the structure which acts as a selectively permeable membrane.


(c) If the cell had been placed in distilled water instead of strong sugar solution, which feature would not have been seen?


(d) Name any one feature of this plant cell which is not present in an animal cell.

 3

The diagram given below represents an experimental set-up to demonstrate a certain process. Study the same and answer the questions that follow:


(a) Name the process.


(b) Define the above-named process.


(c) What would you observe in the experimental set-up after an hour or so?


(d) What control experiment can be set up for comparison?


(e) Keeping –hair, cell and its surroundings, name the parts that correspond to (1) concentrated sugar solution (2) parchment paper and (3) water in the beaker.


(f) Name any other substance that can be used instead of parchment paper in the above experiment.


(g) Mention two advantages of the process to the plants.

 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.