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प्रश्न
Two potato cubes each 1 cm3 in size, were placed separately in two containers (A and 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 somewhat decreased in size. Use the above information to answer the questions that follow:
Name and define the physical process being investigated in this experiment.
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उत्तर
The process being investigated is osmosis. Osmosis is the diffusion of water molecules across a semi-permeable membrane from a more dilute solution (with a lower solute concentration) to a less dilute solution (with a higher solute concentration).
संबंधित प्रश्न
Explain how soaked seeds swell up and burst their seed coats.
Explain why:
The leaves of wilted lettuce, if kept in cold water, become crisp.
Choose the correct answer:
Plasmolysis will occur when the cell is placed in a __________
A leaf cell of a water plant was placed in a liquid other than pond water. After sometime, it assumed a shape as shown below:
Comment on the nature (tonicity) of the liquid surrounding the cell.
In the figure below ‘A’ shows a cell in the normal state and ‘B’ shows the same cell after leaving it in a certain solution for a few minutes.
(i) Describe the change which has occurred in the cell as seen in B.
(ii) Give the technical term for the condition of the cell as reached in B and as it was in A.
(iii) Define the process which led to this condition.
(iv) What was the solution-isotonic, hypotonic or hypertonic, in which the cell was kept?
(v) How can the cell in B, be brought back to its original condition?
(vi) Name the parts numbered 1 to 3.
The diagram given below is of an experiment just at the start. Study the diagram carefully and answer the following questions :
(i) What does the experiment demonstrate?
(ii) Define, the process demonstrated in the experiment.
(iii) What changes are observed after a few hours?
(iv) Give two examples of a semi-permeable membrane.
(v) Which limb of the U-tube contains a more concentrated sucrose solution, A or B?
(vi) Why is the membrane separating the two solutions labeled as semi-permeable membrane?
Given below is the figure of an experimental set up to demonstrate root pressure.
(i) Define root pressure.
(ii) What change would you observe in the water level after some time?
(iii) What role is being played by the root pressure in the given experiment?
(iv) Why the oil has been sprinkled on water?
In an experiment, two sets of apparatus were set up as shown below:
In A there is a concentrated sugar solution inside the thistle funnel and red ink in the water outside the funnel. In B there is a concentrated glucose solution with red ink inside the thistle funnel and water outside the thistle funnel.
In both A and B the level of liquid inside the funnels rises up the tubes. In A the sugar solution turns red and in B, the water turns red.
Study the given observations and answer these questions:
- Name the process by which red ink moves in A and B.
- Which type of pressure forces the water molecules to move towards thistle funnels and cause a rise in the water level?
- Where does this process occur in plants and animals?
- What material could be used as a semi-permeable membrane?
Fill in the Blank
The pressure which develops in the cortical cells of root which force a part of the water upward ____________.
Explain the term:
Plasmolysis
