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.
A plant cell is placed in a solution, and its volume initially increases. After a while, the volume increase stops. Which of the following BEST explains why the volume stopped increasing?
The cell membrane reached its maximum stretching capacity.
All available water in the solution was absorbed by the cell.
The cell wall became impermeable to water.
Turgor pressure reached equilibrium with the external solution's osmotic pressure.
Which of the following would have the LEAST effect on the rate of osmosis across a selectively permeable membrane?
The temperature of the solutions
The concentration gradient of the solute
The permeability of the membrane to the solute
The size of the solute molecules
Which characteristic distinguishes facilitated diffusion from simple diffusion across a biological membrane?
Movement down a concentration gradient
Specificity for the transported molecule
Passive transport requiring no energy input
Dependence on membrane fluidity
Which of the following conditions would likely INHIBIT plasmolysis in a plant cell?
Increasing the concentration of solutes in the external solution.
Placing the cell in a hypertonic solution.
Placing the cell in a hypotonic solution.
Decreasing the cell's internal solute concentration.
During plasmolysis, the cell membrane separates from the cell wall. This separation is primarily due to:
The expansion of the cell wall due to increased turgor pressure.
The shrinking of the protoplast due to water loss.
The breakdown of the cell wall by hydrolytic enzymes.
The active transport of water out of the cell.
The heat released during imbibition is primarily due to:
Frictional forces between the imbibant and the liquid.
The release of latent heat of vaporization.
The establishment of hydrogen bonds between the imbibant and the imbibed liquid.
Metabolic activity within the imbibant.
The Casparian strip in the endodermis plays a crucial role in water absorption by:
Increasing the surface area for water absorption.
Preventing water loss from the cortex back to the soil.
Actively transporting water into the xylem.
Forcing water to enter the symplast, allowing for selective uptake of minerals.
Under conditions of high transpiration pull, the primary driving force for water movement through the xylem is:
Root pressure generated by active transport of ions.
Capillary action within the narrow xylem vessels.
Active transport of water molecules by xylem parenchyma cells.
Cohesion and adhesion of water molecules, creating a continuous water column.
The guttation phenomenon observed in some plants is primarily driven by:
High transpiration rates during the day.
Active transport of water into the xylem by xylem parenchyma.
Root pressure exceeding transpiration pull, particularly at night.
Capillary action in the xylem vessels.
The pressure-flow hypothesis explains the translocation of sugars in the phloem. Which of the following statements regarding this hypothesis is INCORRECT?
Active loading of sugars at the source creates a high solute concentration in the sieve tubes.
Water moves from the xylem to the phloem at the source, increasing turgor pressure.
Sugars are unloaded at the sink, lowering the solute concentration and water potential.
Water moves from the sink to the source via the phloem, driven by a pressure gradient.
