Q3 of 67 Page 48

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.

(a) The process shown in the above diagram represents osmosis.


(b) Osmosis is defined as the diffusion of water molecules across a semi-permeable membrane from a more dilute solution, that is, with a lower solute concentration to a less dilute solution, which is with a higher solute concentration.


(c) After an hour so we would observe a gradual rise of the sugar solution in the thistle funnel from its initial level.


(d) To set a control for this experiment the same setup should be taken with plain water filled in both beaker and the thistle funnel and add a marking on the initial position on the thistle funnel.


(e) Keeping in mind the root hair cell and its surroundings the name of the corresponding parts are:


i. Concentrated sugar solution: Cytoplasm of the root hair cell.


ii. Parchment paper: Cell membrane, that is, the semi-permeable membrane.


iii. Water in the beaker: water in the soil.


(f) As parchment paper acts as a semi-permeable membrane the example of another semi-permeable membrane could be cellophane paper or animal bladder.


(g) The two advantages of osmosis to plants are:


i. Osmosis helps maintain turgidity of the cells and in the uptake of water and nutrients from its surrounding.


ii. Regulation of osmosis in the guard cells of the leaves helps in the opening and closing of stomata


More from this chapter

All 67 →
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.

 2

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.

 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.