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प्रश्न
Explain why:
Bacteria and fungi do not grow in pickles, jams, jellies and squashes.
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उत्तर
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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संबंधित प्रश्न
A candidate in order to study the process of osmosis has taken 3 potato cubes and put them in 3 different beakers containing 3 different solutions. After 24 hours, in the first beaker the potato cube increased in size, in the second beaker the potato cube decreased in size and in the third beaker there was no change in the size of the potato cube. The following diagram shows the result of the same experiment:
(i) Give the technical terms of the solutions used in beakers, 1, 2 and 3.
(ii) In beaker 3, the size of the potato cube remains the same. Explain the reason in brief.
(iii) Write the specific feature of the cell sap of root hairs which helps in absorption of water.
(iv) What is osmosis?
(v) How does a cell wall and a cell membrane differ in their permeability?
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
The highest water potential (capacity to move out higher concentrated solution) is that of ______.
Leaves of the sensitive plant wilt and droop down on a slight touch. What mechanism brings about this change?
Give Reasons for the following.
We gargle with saline water in case of throat infection.
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?
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.
Give Technical Term for the following.
Solutions which have the same osmotic pressure.
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
During exosmosis, water moves from inside the cell to the outside of the cell.
Fill in the Blank
A plasmolysed cell has __________ protoplast.
