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Question
Define the cohesive force.
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Solution
The intermolecular force of attraction between two molecules of the same material is called the cohesive force.
Example: The force of attraction between two water molecules.
RELATED QUESTIONS
Differentiate between Turgor pressure and Wall pressure (explain)
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.
Give the equivalent terms for the following:
Pressure of the cell contents on the cell wall
Differentiate between the following:
Plasmolysis and deplasmolysis
The diagram given below represents an experimental set-up to demonstrate a certain process. Study the same and answer the questions that follow:
- Name the process.
- Define the above-named process.
- What would you observe in the experimental set-up after an hour or so?
- What control experiment can be set up for comparison?
- Keeping in mind the root hair, cell and its surroundings, name the parts that correspond to
- concentrated sugar solution
- parchment paper
- water in the beaker
- Name any other material that can be used instead of parchment paper in the above experiment.
- Mention two advantages of the process for the plants.
Two potato cubes each 1 cm3 in size, were placed separately in two containers (A&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 had somewhat decreased in size. Use the above information to answer the questions that follow:
Account for the firmness and increase in the size of the potato cubes placed in water.
A plant cell kept in a drop of water was examined under the low power magnification of a microscope, as shown:
(i) What would you do to bring this cell back to its original condition?
(ii) What scientific term is used for such condition?
(iii) Draw the same cell if it is kept in a strong sugar solution.
The beaker is divided into two chambers A and B. The big circle represents solute and the small circles solvent.
(i) What can you say about the size of the holes in the membrane, if it is to behave semi- permeably between these two?
(ii) Will the solvent molecules pass through the membrane from left to right, from right to left, in either direction or in both directions?
(iii) In which direction will there be a net movement of solvent molecules?
Mention, if the following statement is True or False. If false rewrite the wrong statement in its correct form:
Plasmolysis makes the cell turgid.
