The movement of particles from region of higher concentration to region of lower concentration is called?

Appeared in: AIIMS Patna NO - 2020

Explanation

Diffusion is defined as the net movement of particles from a region of higher concentration to a region of lower concentration.
This movement occurs down a concentration gradient and is a form of passive transport, meaning it does not require the cell to expend metabolic energy (ATP).
The process continues until the particles are evenly distributed, reaching a state of equilibrium.
A primary example in the human body is the exchange of oxygen and carbon dioxide between the alveoli and the bloodstream.

Option B: Filtration is the movement of water and solutes across a membrane due to a pressure gradient (hydrostatic pressure), not a concentration gradient.
Option C: Osmosis specifically describes the movement of a solvent (usually water) across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.
Option D: Hydrolysis is not a transport mechanism; it is a chemical decomposition reaction in which a compound is broken down by reacting with water.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Principles of substance transport across membranes as background academic context rather than a clinical decision trigger.
Understanding diffusion is fundamental for nurses to grasp how gas exchange occurs in the lungs, how nutrients are absorbed, and how certain medications are delivered (e.g., transdermal patches).
Impaired diffusion, such as in pulmonary edema or fibrosis, leads to hypoxia because oxygen cannot efficiently move from the lungs into the blood.
What if? If a patient has a thickened alveolar membrane due to a lung disease like fibrosis, the diffusion distance for oxygen increases. This would impair gas exchange, leading to chronic hypoxemia, and the patient would likely require supplemental oxygen therapy.

How to Approach the Question

First, identify the key process described in the question stem: 'movement of particles from region of higher concentration to region of lower concentration'.
Recognize that this phrase is the classic definition of moving 'down a concentration gradient'.
Systematically review the definitions of each option.
Diffusion is the movement of solutes down their concentration gradient.
Filtration is movement driven by a pressure gradient.
Osmosis is the movement of a solvent (water) across a membrane towards a higher solute concentration.

Concept Tested & Keywords

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

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

E6 Physiology Guyton 4SAE Part 1 p. 72-74

Practise the full AIIMS Patna NO - 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.