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Question
Explain why:
Bacteria and fungi do not grow in pickles, jams, jellies and squashes.
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
Give appropriate biological or technical terms for the following :
Movement of molecules of a substance from their higher concentration to lower concentration when they are in direct contact.
Name the following:
The condition of a cell placed in a hypotonic solution.
(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.
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
(1)What is the state of the cell shown in the cell shown in the diagram?
(2)Name the structure which acts as a selectively permeable membrane.
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(4)Name any one feature of this plant cell which is not present in an animal cell.
Differentiate between the following
Endosmosis and Exosmosis
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.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Osmosis is defined as the movement of water from a concentrated sugar solution to a dilute sugar solution.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
The plasma membrane permits the passage of all solutes and water.
Multiple Choice Question:
Plasma membrane controls:
Explain the Term: Diffusion
