EVERYDAY SCIENCE

Detailed explanation-1: -Inside the red blood cell, oxygen reacts chemically with hemoglobin and is transported by both free and hemoglobin-facilitated diffusion. Oxygen diffuses through the cell membrane and is transported in blood plasma by free diffusion and by convection.

Detailed explanation-2: -Oxygen moves by diffusion from an area of higher concentration inside the lungs to an area of lower concentration in the blood. It is then carried away by red blood cells. The blood leaving the lungs now has a high concentration of oxygen. It travels round the circulatory system to the cells in tissues and organs.

Detailed explanation-3: -In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells.

Detailed explanation-4: -In simple diffusion, small noncharged molecules or lipid soluble molecules pass between the phospholipids to enter or leave the cell, moving from areas of high concentration to areas of low concentration (they move down their concentration gradient).

Detailed explanation-5: -Oxygen and carbon dioxide move across cell membranes via simple diffusion, a process that requires no energy input and is driven by differences in concentration on either side of the cell membrane.