O.P.,T.P., I.P., D.P.D Questions in English

(B) The correct equation for Diffusion Pressure Deficit $(DPD)$ is $DPD = OP - TP$,where $OP$ is Osmotic Pressure and $TP$ is Turgor Pressure.
Option $B$ states $DPD = -OP + TP$,which is mathematically equivalent to $DPD = TP - OP$. This is incorrect because $DPD$ is defined as the difference between the osmotic pressure of the solution and the turgor pressure of the cell $(OP - TP)$.

(A) Water always moves from a region of lower $DPD$ (Diffusion Pressure Deficit) to a region of higher $DPD$.
Given $DPD$ values are:
Cell $A = 5 \text{ atm}$
Cell $B = 3 \text{ atm}$
Cell $C = 4 \text{ atm}$
Cell $D = 2 \text{ atm}$
Comparing these values, the sequence of increasing $DPD$ is $D (2 \text{ atm}) < B (3 \text{ atm}) < C (4 \text{ atm}) < A (5 \text{ atm})$.
Therefore, the water will move in the direction $D \rightarrow B \rightarrow C \rightarrow A$.

(A) Xerophytes are plants adapted to survive in environments with little liquid water,such as deserts.
To survive in water-deficient soils,xerophytes maintain a high Osmotic Pressure $(OP)$ within their cells.
This high $OP$ helps them to absorb water from the soil even when the water potential of the soil is very low.
Therefore,both the Assertion and the Reason are correct,and the high $OP$ is the reason why they can retain water effectively.

(A) In plant cells,the pressure potential $(\psi_P)$ is usually positive due to the pressure exerted by the cell contents against the cell wall.
This pressure is known as turgor pressure.
When water enters a plant cell,it causes the cell to swell,building up pressure against the cell wall,which is defined as turgor pressure.
Therefore,the positive value of $\psi_P$ is referred to as turgor pressure.

(A) When water enters a plant cell, it creates a pressure against the cell wall due to the swelling of the protoplast. This pressure is known as Turgor pressure $(P)$.
In response, the rigid cell wall exerts an equal and opposite pressure on the protoplast, which is known as Wall pressure $(Q)$.
Therefore, $P = \text{Turgor pressure}$ and $Q = \text{Wall pressure}$.

(A) Osmotic pressure is the external pressure applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane.
In biological terms,it is the pressure required to stop the process of osmosis completely.
Therefore,the correct definition is the pressure that stops the process of osmosis.

(C) The Diffusion Pressure Deficit $(DPD)$ is defined as the difference between the diffusion pressure of pure water and the diffusion pressure of a solution. It is calculated as $DPD = OP - TP$,where $OP$ is Osmotic Pressure and $TP$ is Turgor Pressure.
$1$. For a Turgid cell: $OP = TP$,therefore $DPD = 0$ (minimum).
$2$. For a Flaccid cell: $TP = 0$,therefore $DPD = OP$.
$3$. For a Plasmolysed cell: $TP$ is negative,therefore $DPD = OP - (-TP) = OP + TP$ (maximum).
Thus,the order of $DPD$ is: Plasmolysed cell $>$ Flaccid cell $>$ Turgid cell.

(B) The pressure exerted by the protoplast against the cell wall due to the entry of water is known as $Turgor \text{ pressure}$.
According to the physical laws, the cell wall exerts an equal and opposite pressure on the protoplast, which is known as $Wall \text{ pressure}$.
Therefore, the correct answer is $Turgor \text{ pressure}$.

(B) $1$. A Turgid cell is a cell that is fully distended with water. In this state, the Turgor Pressure $(T.P.)$ is equal to the Osmotic Pressure $(O.P.)$, which makes the Diffusion Pressure Deficit $(D.P.D.)$ equal to zero $(D.P.D. = O.P. - T.P. = 0)$. Thus, $i-b$.
$2$. Pure water has the highest water potential, which is defined as zero at standard temperature and pressure. Thus, $ii-c$.
$3$. A Flaccid cell is a cell that has lost water and is no longer turgid. In a flaccid cell, the Turgor Pressure $(T.P.)$ is zero. Thus, $iii-a$.
Therefore, the correct matching is $i-b, ii-c, iii-a$.

(B) The movement of water is determined by the Diffusion Pressure Deficit $(DPD)$,where $DPD = OP - TP$.
For cell $A$: $DPD = 100 - 50 = 50 \ bars$.
For cell $B$: $DPD = 100 - 60 = 40 \ bars$.
Water always moves from a region of lower $DPD$ to a region of higher $DPD$.
Since cell $B$ has a lower $DPD$ $(40 \ bars)$ compared to cell $A$ $(50 \ bars)$,water will flow from cell $B$ to cell $A$.

(C) The $DPD$ (Diffusion Pressure Deficit) of a cell is defined as the difference between the diffusion pressure of pure water and the diffusion pressure of the solution.
It is mathematically expressed as $DPD = OP - TP$, where $OP$ is the Osmotic Pressure and $TP$ is the Turgor Pressure.
$OP$ represents the pressure that prevents the entry of pure water into the solution, while $TP$ is the pressure exerted by the cell contents against the cell wall.
As water enters the cell, $TP$ increases, which reduces the $DPD$ of the cell.

(B) The $DPD$ (Diffusion Pressure Deficit) is defined by the equation: $DPD = OP - TP$,where $OP$ is Osmotic Pressure and $TP$ is Turgor Pressure.
When a plant cell is fully turgid,the Turgor Pressure $(TP)$ becomes equal to the Osmotic Pressure $(OP)$.
Therefore,$DPD = OP - OP = 0$.
Thus,in a fully turgid cell,the $DPD$ is zero.