The process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one is called?

1. A

   Ultra filtration

2. B

   Active transport

3. C

   Osmosis

4. D

   Diffusion

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

• Osmosis is defined as the movement of a solvent (typically water in biological systems) across a semipermeable membrane.
• The movement occurs from an area of lower solute concentration (higher water potential) to an area of higher solute concentration (lower water potential).
• This process is passive, meaning it does not require metabolic energy (ATP).
• The goal of osmosis is to equalize the solute concentrations on both sides of the membrane.
• It is a critical process for maintaining cell volume and fluid balance within the body.

Why Other Options Were Wrong

• Option A: Ultrafiltration is the movement of fluid and solutes across a membrane driven by a pressure gradient (hydrostatic pressure), not a solute concentration gradient. The question describes movement based on concentration differences.
• Option B: Active transport moves solutes against their concentration gradient (from a less concentrated area to a more concentrated one) and requires energy (ATP). The question describes the passive movement of a solvent.
• Option D: Diffusion is the movement of solutes from an area of higher concentration to an area of lower concentration. The question specifically describes the movement of the solvent (water), not the solute.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Cellular Transport Mechanisms as background academic context rather than a clinical decision trigger.
• Understanding osmosis is crucial for nurses when administering intravenous (IV) fluids. The tonicity (concentration) of the IV solution relative to the patient's blood plasma determines how fluid will shift between the bloodstream and the body's cells.
• Isotonic solutions (e.g., 0.9% Normal Saline) have the same concentration as body fluids and are used for volume expansion without causing major fluid shifts.
• Hypotonic solutions (e.g., 0.45% Saline) cause fluid to move into cells, which is useful for treating cellular dehydration but can be dangerous if it leads to cell swelling (lysis), especially in the brain.

How to Approach the Question

• First, carefully read the question and identify the key terms: 'molecules of a solvent', 'pass through a semipermeable membrane', 'from a less concentrated solution into a more concentrated one'.
• Focus on the distinction between 'solvent' (the liquid, usually water) and 'solute' (the dissolved substance). The question is about the solvent's movement.
• Analyze the direction of movement: from 'less concentrated' (meaning more solvent, less solute) to 'more concentrated' (less solvent, more solute). This describes movement down the solvent's concentration gradient.
• Evaluate each option based on its scientific definition.
• Eliminate 'Diffusion' because it primarily describes solute movement.
• Eliminate 'Active transport' because it requires energy and moves substances against a gradient.

Concept Tested & Keywords

• Concept Tested: Cellular Transport Mechanisms
• Stem keywords: solvent, semipermeable membrane, less concentrated solution, more concentrated solution
• Lead-in keywords: is called

Question ID

QsUiKKr9cL9TUKRkjM8kIN

Copy ID

Reference Book

E6 Physiology Ganong 27e Vol 1 Part 1 p. 15-17

E6 Physiology Essentials Sembulingam 10e Part 1 p. 52-54

E6 Nursing Fundamentals Taylor p. 775-777