What is the primary role of the tonoplast in plant cells?
Answer and explanation
Correct answer: D. Membrane enclosing the central vacuole that actively accumulates ions against concentration gradients
- Step 1: Mature plant cells possess a prominent central vacuole occupying up to of the cellular volume.
- Step 2: The single membrane that delimits the central vacuole from the cytoplasm is called the tonoplast.
- Step 3: The tonoplast contains V-type -ATPases that pump protons into the vacuole, establishing an electrochemical gradient that drives uphill transport of ions and secondary metabolites.
Answer
It is a semi-permeable membrane enclosing the central vacuole that actively accumulates ions against concentration gradients.
Why not the others: Outer layer of chloroplast envelope is a distinct double-membrane boundary; Protein coat of oil droplets describes oleosin layers on lipid bodies; Intercellular junction between adjacent plant cells is called a plasmodesma.
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