Tag: osmotic relations of plant cells

Questions Related to osmotic relations of plant cells

Mammalian liver cells will swell, if they are kept in 

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. Hypertonic solution

  2. Hypotonic solutions

  3. Isotonic solution

  4. Isothermal solutions

Show answer
Correct Option: B
Explanation:

A Hypertonic solution is a solution, which contains higher solute concentration. If mammalian liver cells are kept in hypertonic solution then exosmosis will occur. Exosmosis is a process in which outward movement of water molecules takes place from inside of lower solute concentration to the outside of higher solute concentration through the cell membrane. Due to exosmosis, mammalian liver cells will shrink. So, the correct answer is option B.

Grapes were put in a concentrated sugar solution. On examination after 12 hours, the grapes were shrunken. This is because

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. Grapes become sweeter

  2. Water evaporates from the solution

  3. Sugar induces disintegration of grapes

  4. Loss of water from grapes by osmosis

Show answer
Correct Option: D
Explanation:

Grapes were put in sugar solution i.e., in hypertonic solution. Due to which exosmosis occurs in which outward movement of the water molecules from the lower solute concentration to higher solute concentration takes place through grapes covering. It results in shrinking of grapes. Therefore, option D is correct.

When amoeba is placed in a hypertonic medium, it shrinks. Why does this happen? 

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. Due to exosmosis

  2. Due to endosmosis

  3. Due to both

  4. None of the above

Show answer
Correct Option: A
Explanation:

If amoeba is kept in hypertonic solution then exosmosis occurs in which the water molecules move outward from cell of lower solute concentration to surrounding medium of higher solute concentration through the cell membrane. Due to exosmosis, amoeba will shrink. 

Therefore, option A is correct. 

A single-celled organism which has contractile vacuole to move water from inside to outside of the cell was studied in an experiment in which the organism was placed in water with different salt concentrations. The rate at which the contractile vacuole contracted to pump out excess water was recorded.

Salt conc. Rate of contractile vacuole contractions per minute
Very high 2
High 8
Medium 15
Low 22
Very Low 30

Which of the following explains the observed relationship between the rate of contractile vacuole contraction and the salt concentration?

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. When the salt concentration outside the cell is very low, osmosis causes body salts to move outside the cell, increasing water content in body and the contractile vacuole needs to contract rapidly

  2. When the salt concentration outside the cell is very high, diffusion causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly

  3. When the salt concentration outside the cell is very low, diffusion causes water to move outside the cell, and the contractile vacuole contractions are increased

  4. When the salt concentration outside the cell is very high, osmosis causes water to move outside the cell, and the contractile vacuole does not need to contract as rapidly

Show answer
Correct Option: D
Explanation:

The lower the concentration of the salt solution, the higher will be the water potential of that solution. The higher the water potential, the greater is the tendency for water to enter the cell by osmosis. If there is more water entering by osmosis, then the contractile vacuole will have to fill up and empty more frequently. 

So, the correct answer is option D.

All of the following involves osmosis except

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. Water passing from a root hair to adjacent cells.

  2. Water passing from a xylem vessel element to xylem vessel element above it.

  3. Water entering a mesophyll cell from the xylem vessel element.

  4. Water from soil entering a root hair.

Show answer
Correct Option: B
Explanation:

Water passing from a xylem vessel element to xylem vessel element above it due to the transpiration pull exerted by the mesophyll cells. However, the transfer of water from the soil to the root is due to osmosis.

Therefore, the correct answer is option B.

OP of a cell can be measured by 

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. Manometer

  2. Photometer

  3. Calorimeter

  4. Plasmolysis

Show answer
Correct Option: D
Explanation:

Manometer is a device that is used to measure pressure. Photometer is a device that is used to the intensity of light. Calorimeter is a device that is used to measure the amount of heat involved in a reaction. Osmotic pressure is the pressure that must be applied in order to prevent the passage of solvent due to osmosis. The OP of a cell can be measured by plasmolysis. The OP of a cell is equal to the OP of a solution that results in the incipient plasmolysis in the cell.

Thus, the correct answer is option D.

In root hair, water enters due to 

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. Diffusion

  2. W.P.

  3. T.P.

  4. O.P.

Show answer
Correct Option: D
Explanation:

(A) Diffusion is the movement of the water molecule from higher concentration to lower concentration.

(B) Wall pressure is the pressure applied by the cell wall against the turgor pressure.
(C) Turgor pressure is pressure applied against the wall pressure.
(D) Osmotic pressure is the pressure applied to prevent osmosis that is the movement of the water molecule from a lower solute concentration to a higher concentration through a semi-permeable membrane. Absorption of water through roots is by osmotic pressure.
So, the correct answer is 'Osmotic pressure'.

A cell with DPD = 5 is surrounded by A, B, C and D cells having O.P. and T.P. 5 and 4, 7 and 5, 3 and 2, zero and zero respectively. From which cell will the water withdraw faster?

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. D

  2. C

  3. B

  4. A

Show answer
Correct Option: A
Explanation:

DPD is the difference between Osmotic pressure and Turgor pressure. 

For cell A the DPD is 1.
For cell B the DPD is 2.
For cell C the DPD is 1
For cell D the DPD is 0.
So, the correct answer is 'D'.

Colligative property is :
1. Osmotic pressure
2. Vapour pressure
3. Cohesive force
4. Surface tension

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. 1, 2, 3

  2. 1, 2

  3. 2, 4

  4. 1, 3

Show answer
Correct Option: B
Explanation:

Colligative properties are the characteristics of solutions which depend on the ratio of the number of solute particles to the number of solvent molecules in a solution. It does not depend on the quality of the chemical species present.

Colligative properties include vapor pressure, elevation of boiling point, depression of freezing point and osmotic pressure because, over here all depends only on the number of dissolved particles.
So, the correct answer is option B.

A RBC and a plant cell having same O.P. are placed in distilled water, then 

bio-chemistry absorption by roots - the processes involved osmotic relations of plant cells transport across membrane imbibition and its importance

  1. None undergoes any change.

  2. Plant cell swells up and bursts but plant cell remains about the same size.

  3. RBC swells up and bursts but there is no change in plant cell.

  4. Both decrease in size and collapse.

Show answer
Correct Option: C
Explanation:

Distilled water is a hypotonic solution contained within the red blood cell membranes that is why distilled water will diffuse into the red blood cells and cause them to burst.

So, the correct answer is 'RBC swells up and burst but there is no change in the plant cell'.