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प्रश्न
Give Reasons for the following.
Salt and sugar are used in preserving food.
उत्तर
Salt and sugar increase the concentration of food, destroying bacteria by plasmolysis.
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संबंधित प्रश्न
Distinguish between the following:
Hypotonic and Hypertonic solutions
Choose the correct answer:
Osmosis involves diffusion of ___________
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.
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.
Give Reasons for the following.
It is necessary to maintain a normal osmotic concentration of the blood.
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?
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?
Name the following:
Condition of cell in which the cell content are shrunken.
Fill in the Blank
Raisin swells up when kept in a __________ solution.
When a cell in solution shrinks and loses its shape, then the solution is ______.
