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.
Guttation in plants is primarily caused by:
Root pressure exceeding transpiration pull
High transpiration rates during the day
Opening of stomata at night
Active transport of water into xylem vessels
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
Facilitated diffusion differs from simple diffusion in that:
Facilitated diffusion requires membrane proteins, while simple diffusion does not.
Facilitated diffusion moves substances against their concentration gradient, while simple diffusion moves them down their concentration gradient.
Facilitated diffusion requires energy expenditure, while simple diffusion does not.
Facilitated diffusion occurs only in plant cells, while simple diffusion occurs in all cells.
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
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
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
The movement of oxygen from alveoli to pulmonary capillaries is best described as:
Active transport requiring ATP
Facilitated diffusion via carrier proteins
Simple diffusion driven by a partial pressure gradient
Osmosis across a semipermeable membrane
A researcher applies a potent respiratory inhibitor to the root cells of a plant. Which of the following would be MOST directly affected, ultimately impacting root pressure?
Water potential gradient between the soil and root hairs
Cohesion and adhesion of water molecules in the xylem
Transpiration pull from the leaves
Active transport of ions into the xylem
Under which of the following specific environmental conditions would guttation be LEAST likely to occur?
Cool, humid night with high soil moisture
Warm, humid morning with adequate soil moisture
Cool, dry night with moderate soil moisture
Hot, dry day with low soil moisture
If the water potential of root cells is -0.5 MPa and the water potential of the xylem sap is -0.7 MPa, which statement BEST describes the movement of water?
Water will move from the xylem into the root cells
Water will move from the root cells into the xylem
There will be no net movement of water
Water will move equally in both directions
