Tag: plant water relation

Questions Related to plant water relation

Choose the correct answers from the alternatives given.
Which one of the following does not increase the rate of diffusion?

botany plant water relation active transport and passive transport types of plant transport atp

  1. Decreasing the size of the molecules

  2. Increasing the size of the molecules

  3. Increasing the temperature of the fluid

  4. Increasing the concentration of the molecule

Show answer
Correct Option: B
Explanation:

Diffusion is the movement of molecules or ions from the region of their higher concentration to the region of their low concentration. Diffusion is obvious in gases and liquids but rare in solids. Diffusion rates are affected by the concentration gradient, the permeability of the membrane separating different molecules, temperature and pressure. 

Hence, the correct answer is 'Increasing the size of the molecules'.

The process of diffusion is involved in _____________.

botany plant water relation active transport and passive transport types of plant transport atp

  1. Respiration

  2. Photosynthesis

  3. Transpiration

  4. All of these

Show answer
Correct Option: D
Explanation:

Diffusion keeps the cell walls of the internal plant tissues moist. It is a means of spreading of ions and other substances throughout the protoplast. Transpiration or loss of water in vapour forms is a diffusion process. Exchange of gases (CO2(CO2 and O2)O2) during photosynthesis and respiration between the plant interior and outside air also occurs through diffusion.

In plants diffussion occurs in

botany plant water relation active transport and passive transport types of plant transport atp

  1. Exchange of gases

  2. Transpiration

  3. Absorption of water by roots

  4. Opening of flowers

Show answer
Correct Option: A
Explanation:

The movement of oxygen and carbon dioxide in and out of leaves during photosynthesis occurs by diffusion.

So the correct option is 'exchange of gases'.

A plant cell was put into a solution of substance A at a concentration of $200\ mmol/L$. The rate of uptake into the cell was measured as $5\ mmol/minute$. When the cell was placed in a solution of substance A at a concentration of $400\ mmol/L$, the rate of uptake was $10\ mmol\ per\ minute$. When the experiment was repeated with substance B, the rate of uptake was $10\ mmol\ per\ minute$ at both concentrations of the substance. Which of the following provides the best explanation of the results?

botany plant water relation active transport and passive transport types of plant transport atp

  1. Substance A appears to move into the cell by active transport, and B by diffusion

  2. Substance A and B appear to move into the cell by passive transport

  3. Substance A and B appear to move into the cell by active transport

  4. Substance A appears to move into the cell by diffusion and substance B by active transport

Show answer
Correct Option: A
Explanation:
In the active transport, as the concentration of the solution increases, so does the amount of uptake in a cell. And in diffusion, the amount of the uptake of a substance in a cell is usually not affected by the concentration of the solution.

So, the correct answer is 'Substance A appears to move into the cell by active transport and B by diffusion'.

Which of the following is zero in fully turgid cell?

botany plant water relation active transport and passive transport types of plant transport atp

  1. DPD and ${ \Psi } _{ P }$

  2. DPD and ${ \Psi } _{ W }$

  3. OP and ${ \Psi } _{ W }$

  4. TP and ${ \Psi } _{ P }$

Show answer
Correct Option: A
Explanation:

DPD is the difference in the diffusion pressure of the solution and a pure solvent when both are subjected to the same atmospheric pressure. When the increasing turgor pressure becomes equal to the decreasing osmotic pressure, the entry of the water into the cell would stop. This is called the turgid condition of the cell. This is when DPD equals zero.

Pressure potential is the positive pressure developed in the system due to the osmotic entry of water into it. It is negative in plasmolysed cell and xylem vessel and zero for the turgid cell.
Hence, the correct answer is 'DPD and ${ \Psi } _{ P }$'

Choose the correct answers from the alternatives given.
In a fully turgid cell, which one of the following would be zero?

botany plant water relation active transport and passive transport types of plant transport atp

  1. Suction pressure

  2. Osmotic pressure

  3. Wall pressure

  4. Turgor pressure

Show answer
Correct Option: A
Explanation:

Suction pressure or the DPD is given as the difference of osmotic pressure and the turgor pressure, $DPD = OP - TP$

In a fully turgid cell, the entry of water into the cell causes the development of the turgor pressure, therefore, TP cannot be zero. When the increasing turgor pressure becomes equal to the decreasing osmotic pressure, the entry of water into the cell would stop. This means DPD becomes zero in a fully turgid condition.
Hence, the correct answer is 'Suction pressure'.