Question

The process of exchange of \(\mathrm{O}_{2}\) from the atmosphere with \(\mathrm{CO}_{2}\) produced by the cell is called (a) Cellular respiration (b) Breathing (c) Ventilation (d) Perfusion

Short answer

The correct answer is (a) Cellular respiration. This process is responsible for the exchange of O2 from the atmosphere with CO2 produced by the cell.

Step-by-step solution

Understanding Cellular respiration

Cellular respiration is the process by which cells in plants and animals break down sugar and turn it into energy, which is then used to perform work at the cellular level. The process of cellular respiration involves metabolic reactions that convert nutrients such as sugar into carbon dioxide (CO2) and water. In simple terms, it is the process of transforming food into usable cellular energy.

Understanding Breathing

Breathing, also known as ventilation, is the process that moves air in and out of the lungs. The oxygen in the air is taken into the body, and carbon dioxide (a waste product) is exhaled back into the atmosphere.

Comparing with the other options

Perfusion is the process of a body delivering blood to a capillary bed in its biological tissue, so it's not related with the exchange of gases. Ventilation is another term for breathing, so it's not the process of exchange of O2 from the atmosphere with CO2 produced by the cell.

Key concepts

Cellular Respiration

Cellular respiration is a vital process occurring within the cells of all living organisms. It is how cells convert glucose into usable energy, specifically ATP (adenosine triphosphate). This energy is crucial for various biological functions. The process involves three main stages:

• Glycolysis: Takes place in the cell’s cytoplasm, where glucose is split into two molecules of pyruvate, producing a small amount of ATP and NADH.
• Krebs Cycle (Citric Acid Cycle): Occurs in the mitochondria, where pyruvate is broken down further, releasing more high-energy electrons carried by NADH and FADH₂.
• Electron Transport Chain: This final stage happens in the inner mitochondrial membrane, where electrons from NADH and FADH₂ are transferred through a chain of proteins. This produces a large amount of ATP by oxidative phosphorylation.

In summary, cellular respiration is the process converting nutrients into energy and produces carbon dioxide as a byproduct, which is crucial for energy production in cells.

Breathing

Breathing, or ventilation, is the mechanical process that moves air into and out of the lungs. It is how our bodies obtain oxygen from the environment and expel carbon dioxide, a waste product of cellular respiration. Breathing involves two primary actions:

• Inhalation: The diaphragm and intercostal muscles contract, expanding the chest cavity and drawing air into the lungs.
• Exhalation: The muscles relax, causing the chest cavity to decrease in volume, pushing air out of the lungs.

This continuous cycle ensures that the blood receives oxygen and releases carbon dioxide effectively. It's important to note that breathing itself doesn't directly perform the exchange of gases at the cellular level, rather it facilitates it by moving air in and out of the lungs.

Gas Exchange

Gas exchange is the crucial process where oxygen is delivered from the lungs to the blood, and carbon dioxide is expelled from the blood to the lungs. This occurs in the alveoli, tiny air sacs in the lungs with thin walls providing a large surface area for diffusion.

Here's how it works:

• Oxygen enters the alveoli during inhalation and diffuses across the alveolar membrane into the capillaries, where it binds to hemoglobin in red blood cells.
• Carbon dioxide, a byproduct of cellular respiration, diffuses from the blood into the alveoli to be exhaled.

This delicate process is driven by differences in partial pressures of these gases. Oxygen diffuses into the blood because its partial pressure is higher in inhaled air, and carbon dioxide leaves the blood because its partial pressure is higher in the blood than in the alveoli. Gas exchange is essential for maintaining proper oxygen and carbon dioxide levels in the body.