NEET Practice Questions (MCQs) with Answers & Solutions

(a) In roots, endodermis is the innermost layer of cortex. Some of the endodermal cells present opposite to the xylem patches are thin walled and are called passage cells or transfusion cells. Passage cells help in transfer of water and dissolved salts from cortex directly into the xylem and ultimately to the pericycle.

(a) : Jamming of wooden frames during rains is caused by swelling of wood due to imbibition. (The absorption of water by the solid particles of a substance without forming a solution is called imbibition).

(a) Water always moves from the area of high water potential to the area of low water potential i.e from less negative potential to more negative potential

(d) : In facilitated diffusion special proteins help move substances across membranes along the concentration gradient without expenditure of energy. Facilitated diffusion is very specific, it allows cell to select substances for uptake. It is sensitive to inhibitors which react with protein side chains.

(a) The modified equation for water potential is

${\mathrm{\Psi }}_{\mathrm{w}}= {\mathrm{\Psi }}_{\mathrm{s}} + {\mathrm{\Psi }}_{\mathrm{p}}$

Where,

 $$\begin{gathered} {\mathrm{\Psi }}_{\mathrm{w}} = \mathrm{Water} \mathrm{Potential} \\ {\mathrm{\Psi }}_{\mathrm{s}} = \mathrm{Solute} \mathrm{Potential} \\ {\mathrm{\Psi }}_{\mathrm{p}} = \mathrm{Pressure} \mathrm{Potential} \end{gathered}$$

(a) Dixon and Jolly (1894) proposed cohesion and adhesion theory. According to the theory a strong cohesive force between the water molecule is responsible for the tensile strength of water column in vessels of conducting tissue xylem.

Introduction

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Transport in Plants

11.1 Means of Transport

11.1.1 Diffusion

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Transport in Plants

11.1 Means of Transport

11.1.1 Diffusion

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Transport in Plants

11.2 Plant water relations

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Transport in Plants