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.
Which condition would MOST significantly inhibit the translocation of sucrose in phloem?
Decreased sucrose concentration in source cells
Increased sucrose concentration in sink cells
Application of a metabolic inhibitor that blocks ATP synthesis in companion cells
Exposure to light
A plant exposed to a fungal toxin exhibits significantly reduced translocation of potassium ions () despite normal transpiration rates. The toxin MOST likely affects which process?
Stomatal opening and closing
Water potential gradient in the xylem
Activity of membrane transport proteins involved in uptake into xylem
Root pressure generation
Researchers observed that inhibiting phloem unloading in a developing fruit resulted in a decrease in sucrose transport to that fruit. However, the transport of certain amino acids to the fruit was unaffected. Which explanation is MOST likely?
Amino acids are transported through the xylem, not the phloem.
Amino acid transport is solely driven by diffusion, unaffected by phloem unloading mechanisms.
Amino acids and sucrose share the same transporters, but amino acids have a higher affinity.
Amino acids are unloaded via a different mechanism than sucrose, potentially utilizing specific transporters independent of sucrose unloading.
The uptake of potassium (K+) by plant roots can be described by the Michaelis-Menten kinetics. If the maximum uptake rate (Vmax) for K+ is reached at a relatively low external K+ concentration, what can be inferred about the affinity of the K+ transporter?
The K+ transporter has a low affinity for K+.
The K+ transporter is non-specific for K+.
The K+ transporter is inhibited by high K+ concentrations.
The K+ transporter has a high affinity for K+.
Researchers observed that a specific plant species accumulates high levels of cadmium (Cd) in its tissues, even when grown in soil with relatively low Cd concentrations. Which transport mechanism is MOST likely responsible for this observation?
Passive diffusion across the cell membrane
Facilitated diffusion through non-specific channels
Active transport through Cd-specific transporters with high affinity
Endocytosis of Cd-containing soil particles
Which of the following best describes the relationship between the movement of water vapor and carbon dioxide through stomata?
They move in the same direction due to the same concentration gradient.
They move in opposite directions due to the same concentration gradient.
They move simultaneously but due to different concentration gradients.
They move sequentially, with one gas moving only after the other has stopped.
If the cohesive forces between water molecules were significantly weaker, what would be the most likely consequence for tall trees?
Increased water absorption
Enhanced transpiration rate
Faster growth
Inability to transport water to great heights
Statement: Root pressure is acidic due to the secretion of organic acids into the xylem.
Reason: Active transport of ions into the xylem lowers the pH.
Choose the correct option:
Both the statement and reason are correct and the reason is the correct explanation for the statement.
Both the statement and reason are correct but the reason is not the correct explanation for the statement.
The statement is correct but the reason is incorrect.
The statement is incorrect but the reason is correct.
Which of the following is NOT a consequence of adding more solute to an unsaturated solution?
Increases the concentration of the solution
Increases the boiling point of the solution
May increase the conductivity of the solution
Decreases the amount of solvent
Which observation in the Girdling Experiment confirms the role of phloem in downward transport?
Swelling of the region above the girdle
Wilting of leaves below the girdle
Increased root growth
No change in stem thickness
