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 with a water potential of -0.65 MPa is placed in a solution with a water potential of -0.30 MPa. Assuming the cell wall is rigid and fully permeable, and the cell membrane is selectively permeable, what will be the pressure potential of the cell at equilibrium?
-0.95 MPa
-0.35 MPa
+0.35 MPa
+0.95 MPa
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 observes that a particular plant cell placed in a solution exhibits incipient plasmolysis. If the solute potential of the cell is -1.2 MPa, what is the MOST likely water potential of the surrounding solution?
-1.2 MPa
-1.0 MPa
-1.4 MPa
-0.8 MPa
A plant cell is placed in a solution with a water potential of -0.8 MPa. The cell's initial solute potential is -1.2 MPa and its pressure potential is 0.4 MPa. After equilibration, which of the following statements about the cell's state is MOST accurate?
The cell will be turgid, with a pressure potential greater than 0.4 MPa.
The cell will be flaccid, with a pressure potential of zero.
The cell will be plasmolyzed, with a pressure potential of zero.
The cell will experience incipient plasmolysis, with a pressure potential slightly above zero.
A researcher observes that water absorption by roots is significantly reduced when the plant is treated with a respiratory inhibitor. Which of the following best explains this observation?
Respiratory inhibitors directly block aquaporin function, preventing water movement.
Respiration is essential for maintaining root cell turgidity, which is directly linked to water absorption.
Active transport of ions into the root cells requires energy, creating a water potential gradient that drives water uptake.
Inhibition of respiration disrupts the cohesion-tension theory, preventing water movement through the xylem.
The diffusion coefficient of a gas is inversely proportional to the square root of its molar mass. If gas A has a molar mass four times that of gas B, under identical conditions, the diffusion rate of gas A will be:
Twice that of gas B
Half that of gas B
Four times that of gas B
One-fourth that of gas B
In a biological system, the diffusion of a lipophilic substance across a cell membrane is primarily limited by:
The hydrophobic core of the lipid bilayer
The aqueous unstirred layers adjacent to the membrane
The presence of membrane proteins
The concentration gradient of the substance
Which of the following scenarios would result in the LOWEST transpiration rate in a mesophytic plant under otherwise normal conditions?
Low atmospheric humidity, dry soil, windy conditions
High atmospheric humidity, dry soil, still air
Low atmospheric humidity, saturated soil, windy conditions
High atmospheric humidity, saturated soil, still air
Consider a plant exhibiting guttation. Which of the following statements regarding the xylem sap at night is MOST accurate?
Transpiration pull generates negative pressure in the xylem
Root pressure generates positive hydrostatic pressure in the xylem
Cohesion-tension theory is the primary driver of xylem sap movement
Xylem sap movement ceases entirely at night
The cohesion-tension theory explains the upward movement of water in plants. Which of the following is NOT a critical component of this theory?
Cohesion of water molecules
Adhesion of water molecules to xylem walls
Transpiration pull creating negative pressure
Active transport of water into xylem by root cells
