Water Potential

Q.

Explain why pure water has the maximum water potential.

Q.

What happens if a pressure higher than atmospheric pressure is applied to pure water or a solution?

Q.

Define water potential.

Q.

Radial vascular bundles occur in

1. stem

2. dicot roots

3. monocot roots

4. both dicot roots and monocot roots

Q. Describe briefly the three physical properties of water which helps in ascent of water in xylem.

Q. When solutes are added to water, its water potential ________.

1. increases
2. decreases
3. increases or decrease depending on the solute
4. will have no effect

Q.

The important driving force of osmosis is __ gradient

Q. Greater the concentration of water in a system,

1. its water potential is lesser
2. its water potential is greater
3. its kinetic energy is lesser
4. its water potential will not change

Q. During absorption of water by roots, the water potential of cell sap is lower than that of

1. pure water and soil solution
2. neither pure water nor soil solution
3. pure water but higher than that of soil solution
4. soil solution but higher than that of pure water

Q. Cell ‘A’ with OP = 10 atm and TP = 5 atm is in contact with a cell ‘B’ having OP = 15 atm and TP =12 atm. The flow of water will be

1. from A to B
2. from B to A
3. equal flow
4. no flow

Q.

What happens when a pressure greater than the atmospheric pressure is applied to pure water or a solution?

Q.

The osmotic potential or solute potential of a plasmolysed cell is -0.5 MPa. Its water potential is = ?

1. 0.5 MPa

2. -0.1 MPa

3. Zero

4. -0.5 MPa

Q. Net movement of water is from

1. none of the above
2. low DPD to high DPD
3. high DPD to low DPD
4. DPD gradient plays no role

Q. The water potential of pure water is _____.

1. More negative

2. Zero

3. Positive

4. Negative

Q. Derive expression for pressure due to liquid column

Q.

Do liquids exert same pressure at same depth? Explain by an example.

Q.

Which one is an incorrect statement?

1. Water potential is the sum of free energy of water molecules in pure water and in any other system.

2. Water potential of pure water is zero.

3. Movement of water is expressed in terms of free energy.

4. Free energy determines the direction by which physical and chemical changes should occur.

Q. Seeds placed in water imbibe the same because of

1. exosmosis
2. higher 𝜳w
3. lower 𝜳w
4. pressure of vacuoles

Q. Under conditions of bright light, which part of the transpiring plant will have the lowest water potential?

1. Xylem vessels in the leaves
2. Xylem vessels in the roots
3. Root hairs
4. Spongy mesophyll of the leaves

Q. If a cell is placed in an isotonic solution, the water potential and will be equal inside and outside of the cell.

1. solute potential
2. water pressure
3. pressure potential
4. turgor pressure

Q. In a plasmolysed cell

1. Turgor pressure is more than wall pressure
2. Water potential is less than osmotic potential
3. Water potential is greater than osmotic potential
4. Water potential is equal to osmotic potential

Q. Two cells with water potential - 10 MPa and - 6 MPa are in direct contact. At equilibrium the water potential each cell is

1. -10 MPa

2. -6 MPa

3. -4 MPa

4. -8 MPa

Q. Define and explain water potential

Q. Water potential of a solution is depicted by

1. 𝜳p
2. 𝜳w
3. 𝜳s
4. all of the above

Q.

In simple diffusion, the rate at which a solute passes through a membrane depends on all of the following EXCEPT the

1. concentration difference from one side of the membrane the other

2. temperature of the solution

3. surface area of the membrane

4. number of carriers in the membrane

Q. Movement of water occurs from

1. higher DPD to lower DPD
2. higher solute concentrations to lower solute concentration
3. lower 𝚿w to higher 𝚿w
4. None of these

Q.

Which form of water has maximum water potential?

Q. Assertion : The chemical potential of pure water at normal temperature and pressure is zero.

Reason : In solution, value of water potential is always positive.

1. If both assertion and reason are true and reason is correct explanation of assertion.
2. If both assertion and reason are true but reason is not the correct explanation of assertion
3. If assertion is true but reason is false.
4. If both assertion and reason are false.

Q.

Briefly describe water potential. What are the factors affecting it?

Q.

Name an instance where pressure can build up in a plant system.