All mentioned complexes (receptor-hormone, antibody-antigen, enzyme-substate) are involved in a molecular recognition.The molecular recognition involves <span>non-covalent </span> interaction between molecules. To form complex, molecules must be complementary in shape and charges, and usually, they are compared to key and lock. This way, the selectivity and specificity of recognition between molecules are assured.
Answer:
Diffusion is the process in which molecules and ions move from a region of high concentration to low concentration. Its also how cells transport waste out of the cell and nutrients into it hence being very crucial. Diffusion also occurs without the expenditure of extra energy using a procedure known as passive transport. (Osmosis is a form of diffusion but deals with water exclusively).
Examples of where diffusion is important;
In the intestines - Digested food molecules such as amino acids and glucose move down the concentration gradient from the intestine into the bloodstream. Wastes such as carbon dioxide or urea travel via diffusion from the body's cells to the bloodstream.
Osmosis plays a major role in living organisms. It aids in the transportation of nutrients from cells to cells and also helps to remove the waste's metabolic products from the cell. The purification of blood in the kidneys is also dependent on the process of osmosis.
<span>You
are right in that bananas contain potassium and K-40 is a naturally
occurring potassium isotope AND the K-40 in an average banana does decay
at a rate of about 31 ATOMS per second (half-life is > 1 billion
years). This is an extremely low level of radiation and nothing to worry
about. Bananas will definitely NOT cause a "nuclear winter."</span>
