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Question
Explain why:
Bacteria and fungi do not grow in pickles, jams, jellies and squashes.
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Solution
Jam, jellies and pickles are kept in hypertonic solution of sugar or salt in which plasmolysis of bacteria and fungi takes place. This kills the bacteria and fungi and hence, pickles, jam and jellies are preserved properly.
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RELATED QUESTIONS
Movement of molecules of a substance from the region of their higher concentration to the region of their lower concentration without the involvement a separating membrane, is called
(a) Mention whether the following statement is true (True) or false (False)
(b) Correct the false statement by altering the last word only.
A plant cell placed in hypotonic solution gets Plasmolysed.
Show by a series of diagrams, the change which a plant cell will undergo when placed in
Hypertonic salt solution
Define the term:
Plasmolysis
Distinguish between the following:
Filtration and diffusion
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?
The diagram below represents an experimental set up to demonstrate a vital process. Study the same and then answer the questions that follow:
(i) Name the process.
(ii) Define the above named process.
(iii) What would you observe in the experimental setup after an hour or so?
(iv) What control experiment can be set up for the above experiment?
(v) Keeping in mind the root hair cell and its surrounding name the part that corresponds to (1) Concentrated sugar solution, (2) Parchment paper, (3) Water in the beaker.
(vi) Name any other substance that can be used instead of parchment paper in the above experiment.
(vii) Mention two advantages of this process to the plant.
Name the following:
The movement of a liquid through a selectively permeable membrane.
Name the following:
Condition of cell in which the cell content are shrunken.
