<span>Food molecules like lipids, proteins and polysaccharides are broken down enzymatically via digestion process, which occurs in our intestine cells (digestive system). Those large polymeric molecules are broken down into their monomer subunits—proteins into amino acids, polysaccharides into sugars, and fats into fatty acids and glycerol. Formed small organic molecules are now ready for the oxidation (a process that produces ATP and consumes O2) which occurs partly in the cytosol and in the mitochondrion. Oxidation processes include glycolysis and citric acid cycle which are differently required in different tissues. Nervous system (nerve cells) rely almost entirely on a constant supply of <span>glucose<span> from the bloodstream. In contrast, liver cells supply glucose to actively contracting muscle system which needs a lot of ATP energy.</span></span></span>
The chemical feature of each group is: native elements – only one element; silicates – silica tetrahedron; phosphates – phosphate tetrahedron; carbonates – one carbon atom with three oxygen atoms; halides – a halogen bonded with a metallic atom; oxides – a metal combined with oxygen; sulfates – sulfur and oxygen
As far as I know, the adrenal glands, when submitted under pressure such as the one described in the example, secrete a substance known as epinephrine which has the tendency of increasing the affected person's heart rate and breathing.
