Biology · Breathing and Exchange of Gases · NEET
No. Breathing is only the first step — drawing atmospheric air in and pushing CO2-rich air out (pulmonary ventilation). Respiration is the complete process of all 5 steps that ends with cells using O2 to release energy. In everyday language people use them as one word, but in NEET Biology they are different.
That line describes how ordinary people speak, not the scientific meaning. The very next section of NCERT lists respiration as 5 separate steps, with breathing/pulmonary ventilation being only step (i). So the phrase means 'in common speech', not 'scientifically equal'. This exact wording is a favourite NTA trap.
Breathing is a physical (mechanical) process — it is only the movement of air caused by pressure changes in the chest. The chemical part (oxygen used to break down glucose and release energy) happens in the last step, cellular respiration, inside the cells.
No. Breathing happens at the lungs (exchange of O2 and CO2 with the atmosphere). Using oxygen inside the cell to release energy is cellular respiration — a different, final step. Do not mix the lung-level event with the cell-level event.
Breathing (pulmonary ventilation) is step (i), the very first step. The order NCERT gives is: (i) breathing, (ii) diffusion of gases at the alveoli, (iii) transport of gases by blood, (iv) diffusion of gases between blood and tissues, (v) cells using O2 (cellular respiration).
Select the sequence of steps in Respiration. A. Diffusion of gases (O2 and CO2) across alveolar membrane. B. Diffusion of O2 and CO2 between blood and tissues. C. Transport of gases by the blood. D. Pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out. E. Utilisation of O2 by the cells for catabolic reactions and resultant release of CO2.
In humans, respiration occurs in the following steps. Arrange these steps in the correct order. A. Diffusion of O2 and CO2 between blood and tissues. B. Diffusion of O2 and CO2 across alveolar membrane. C. Pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out. D. Cellular respiration. E. Transport of gases by the blood.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Breathing = moving air in and out of the lungs (1 physical step). Respiration = the full 5-step process ending in cells using O2 to release energy.
Yes. NCERT uses 'breathing' and 'pulmonary ventilation' as the same thing — it is step (i) of respiration.
Plants exchange gases by simple diffusion through stomata and lenticels; they have no special breathing system or organs like lungs. So they do gaseous exchange, but not 'breathing' in the animal sense.
Cells constantly use O2 to break down glucose for energy and constantly release CO2 (which is harmful). So O2 must be supplied and CO2 removed non-stop, which is why breathing never stops.
Only the last step — cellular respiration inside the cell, where O2 is used to break molecules and release energy. Breathing itself is purely physical/mechanical.
