Tag: absorption by roots - the processes involved

Questions Related to absorption by roots - the processes involved

The space between plasma membrane and cell wall of a plasmolysed cell surrounded by a hypertonic solution is occupied by

  1. Isotonic solution

  2. Hypotonic solution

  3. Hypertonic solution

  4. Water


Correct Option: C
Explanation:

The hypertonic solution involves the movement of a solute particle from low concentration to high concentration. The water will move from a higher concentration to a lower concentration. The cell will swell up.

So, the correct option is 'Hypertonic solution'.

2% NaCl as compared to 18% glucose solution is 

  1. Isoosmotic

  2. Hypoosmotic

  3. Hyperosmotic

  4. None of the above


Correct Option: B

Osmotic pressure of pure water is

  1. 0

  2. 1

  3. 10

  4. 100


Correct Option: A
Explanation:

Osmotic pressure is generated when solutes are added to water. It depends on the concentration of a solution.

If pure water is taken, it has 0 osmotic pressure.
So the correct answer is '0'.

Choose the wrong statement.

  1. Cells swell in hypertonic solutions and shrink in hypotonic solutions.

  2. Water potential is the kinetic energy of water which helps in movement of water.

  3. Absorption of water by seeds and dry wood takes place by special type of diffusion called imbibition.

  4. $ \Psi _s $ is always negative.


Correct Option: A
Explanation:

The solute potential is always negative as it reduces osmotic pressure.

Absorption of water by seeds and embryo takes place by imbibition which leads to their growth and swelling respectively.
Water potential is the energy of water that helps it in moving.
Cells absorb water when kept in hypotonic solutions and they swell up while they lose water when kept in hypertonic solutions and shrink.
So the correct answer is 'Cells swell in hypertonic solutions and shrink in hypotonic solutions'.

Osmotic pressure of a cell kept in water is chiefly regulated by

  1. Vacuoles

  2. Plastids

  3. Ribosomes

  4. Mitochondria


Correct Option: A
Explanation:

Vacuoles are the organelles that store all the extra water and salts that are the basis of creating osmotic pressure in the cell. The vacuole takes up a huge central place in the cell. The solution outside the cell is hypertonic, hypotonic or isotonic with respect to the contents inside the vacuole. Plastids are the centres for photosynthesis, Ribosomes are small granule-like structures that help in protein synthesis whereas mitochondria generate energy for the cell by utilising sugars. 

So the correct answer is 'Vacuoles'.

RBC placed in distilled water will

  1. Burst

  2. Shrink

  3. Stick to one another

  4. Divide


Correct Option: A
Explanation:

RBCs placed in distilled water will burst because distilled water is extremely hypotonic to the cytoplasm of the cell. This will involve the intake of enormous amounts of water and the cells will burst.

So the correct answer is 'Burst'.

Flaccid cell means

  1. Cell with turgidity

  2. Plasmolysed cell

  3. The cell in which water flows in and out of cell are in equilibrium

  4. The cell kept in hypotonic solution


Correct Option: C
Explanation:

When a cell is placed in an hypertonic solution water is transported out of the cell and the cell shrinks or shrivels or plasmolysed. On contrary when the cell is placed in hypotonic solution the water flows into the cell causing the cells to swell and finally leading to their lysis. However, when the cells are placed in isotonic solutions there will be continuous flow of water in and out of the cell and the cell is said to be in flaccid condition. Thus, the correct option of C.

The osmotic pressures of $0.1$ glucose and $0.1$M sucrose solutions are the same because ______________________.

  1. Both are carbohydrates

  2. These are different compounds having different molecular weights

  3. Both are present in the same concentration

  4. Glucose is reducing sugar while sucrose in non-reducing sugar


Correct Option: A

In plant cells, which of the following are important determinants of movement of molecules in or out of the cell?

  1. Cell wall and cell membrane

  2. Cell wall and tonoplast

  3. Cell wall and glycocalyx

  4. Cell membrane and the membrane of the vacuole


Correct Option: A

When a plasmolysed cell is placed in a hypotonic solution then water will move inside the cell this will happen due to which force

  1. DPD

  2. OP

  3. WP

  4. None of them


Correct Option: B
Explanation:
The force produced because of the osmotic pressure between the plasmolyzed cell and the hypotonic solution is responsible for the movement of water inside the cells.
So, the correct answer is 'OP'.