Simple Diffusion – Class 11 | Chapter – 11 | Biology Short Notes Series PDF

Simple Diffusion: Diffusion is defined as the net movement of a substance or molecules from a region of higher concentration to a region of lower concentration. It is very useful in the separation of a variety of gases. Diffusion is impossible when the concentration gradients of both regions are the same.

Simple Diffusion is the process in which solutes are passed through the concentration gradient in a solution across a semipermeable membrane. The assistance of membrane proteins is not required in this process of diffusion wherein substances move from higher concentration to lower. The process is conducted by the actions of hydrogen bonds which form between solutes and water molecules. Molecules of water move in to surround the solute molecules that maximizes hydrogen bonding.

Examples of Simple Diffusion

  • Steroid hormones can move freely across different membranes down their concentration gradient. So, this is an excellent example of simple diffusion.
  • At the time of food digestion, oxygen is transferred into the blood from the lungs. Also, oxygen is transferred into the muscles from the blood cells. 
  • In the body of pregnant women, food and oxygen travel from the mother’s body into the fetus.
  • Bacteria have single-celled microorganisms. Bacteria deliver water, oxygen, and nutrients to the cytoplasm. No specialised organelles in bacteria perform this type of activity.
  • Dialysis is an artificial process that partially replaces renal function. Dialysis is based on the principle of diffusion of solutes and ultrafiltration of fluid across a semipermeable membrane.

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By Team Learning Mantras