Q106 · UPPSC Prelims 2021 · Set D · General Studies

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After cutting cucumber if salt is added, then water comes out due to

A Active transport
B Passive transport
C Osmosis
D Diffusion

Correct answer: (c) Osmosis

Explanation

  1. A

    Active transport

    Active transport moves solutes against a gradient using metabolic energy (ATP). Water leaving salted cucumber slices is not an ATP-driven pump of water. Calling it active transport mislabels a passive water movement.

  2. B

    Passive transport

    Passive transport is a broad class (diffusion, facilitated diffusion, osmosis) without ATP. The question asks the specific process when salt draws water from cucumber cells. Osmosis is the precise name; ‘passive transport’ is too generic for this key.

  3. C

    Osmosis

    (c) Official key: Salt outside the cut cucumber raises external solute concentration, so water moves out of cells across membranes from higher water potential to lower — osmosis. That is why slices weep liquid. Among active transport, passive transport, osmosis and diffusion, the keyed process is osmosis.

  4. D

    Diffusion

    Diffusion is net movement of a substance down its own concentration gradient. Water movement through a selectively permeable membrane under a solute gradient is specially termed osmosis. Diffusion is related but not the keyed name here.

Summary. Official key is (c). Adding salt to cut cucumber creates a hypertonic exterior; water leaves the tissue by osmosis. Active transport would need energy and is the wrong class; ‘passive transport’ and ‘diffusion’ are related but not the specific textbook name. The process to mark is osmosis.