Prepare for NEET Biology Transport in Plants with MCQs & PYQs on NEET.GUIDE. Access free practice, previous year questions, and expert guidance to understand xylem, phloem, and movement of water.
Imagine a U-shaped tube with a selectively permeable membrane separating two solutions. Side A contains a 0.2M sucrose solution, and Side B contains a 0.1M NaCl solution. Initially, the levels are equal. Considering the dissociation of NaCl and the non-penetrating nature of sucrose and NaCl, which side will have a higher level at equilibrium?
Side A
Side B
The levels will remain equal
The membrane will rupture
A researcher is studying facilitated diffusion of a novel solute 'X' across a cell membrane using an artificial lipid bilayer system. They observe that increasing the concentration of X on one side of the membrane increases the rate of transport, but only up to a certain point. Beyond this point, further increases in X concentration do not affect the transport rate. Which of the following BEST explains this observation?
The membrane has reached its maximum permeability for X.
The solute X is being actively transported at higher concentrations.
Saturation of the carrier proteins
The solute X is inhibiting its own transport through feedback regulation.
In a hypothetical cell, the facilitated diffusion of a solute 'Y' is observed to be significantly faster than predicted by simple diffusion models. However, the transport rate plateaus at high concentrations of Y. Which of the following is the MOST likely explanation for this observation?
The cell membrane is selectively permeable to Y.
The solute Y is transported via carrier proteins.
The solute Y is undergoing active transport.
The cell is modifying Y during transport.
Which of the following statements regarding facilitated diffusion is INCORRECT?
It requires transport proteins.
It is a passive process and does not require energy.
It can move molecules against their concentration gradient.
Transport proteins involved can become saturated.
A dry wooden block and a dry gelatine block of equal mass are placed in water. The gelatine block imbibes considerably more water than the wooden block. This difference is primarily attributed to:
The higher density of wood compared to gelatine.
The greater number of hydrophilic colloids in gelatine compared to wood.
The presence of lignin in wood, which repels water.
The lower osmotic potential of gelatine compared to wood.
Which of the following scenarios would result in the LEAST efficient water absorption by a plant's roots?
Slightly acidic soil with optimal nutrient availability
Well-aerated soil with moderate water content
Low soil temperature coupled with high humidity
High soil salinity coupled with low soil oxygen levels
Girdling experiments, where the bark of a tree is removed in a ring around the trunk, demonstrate the importance of phloem for translocation. Which observation is NOT expected after girdling?
Accumulation of sugars above the girdle.
Swelling of the bark above the girdle.
Eventual death of the roots due to lack of nutrients.
Increased sugar concentration above the girdle and decreased sugar concentration below the girdle, with no effect on xylem function.
The cohesion-tension theory explains the ascent of sap in tall trees. Which of the following factors LEAST contributes to the maintenance of the continuous water column?
Active transport of water into xylem vessels
Cohesion between water molecules
Adhesion of water molecules to xylem walls
Transpiration pull generated by evaporation from leaves
Which factor does not significantly influence the rate of diffusion of a solute in a liquid?
Temperature of the liquid
The size and shape of the solute molecules
The presence of other non-interacting solutes
The viscosity of the liquid
Which of the following experimental manipulations would MOST effectively demonstrate the contribution of root pressure to xylem sap ascent in a small herbaceous plant?
Submerging the roots in a hypertonic solution and observing changes in leaf turgor
Measuring the rate of transpiration under varying light intensities
Removing the apical bud and observing the effect on guttation
Measuring exudation rate from a cut stem stump after applying a respiratory inhibitor to the roots
