The immediate principles or biomolecules

If a physical analysis of living matter is carried out, so that we can separate each of the substances that compose it without them being altered, we arrive at the so-called immediate principles or biomolecules. The methods used for this analysis are evaporation, filtration, distillation, dialysis, crystallization, electrophoresis, and centrifugation.

The immediate principles can be:

• Simple: when the molecules are made up of atoms of the same chemical element, as in the case of oxygen (O₂) and nitrogen (N₂).
  • O₂ is necessary for aerobic respiration in aerobic bacteria and in the mitochondria of animal and plant cells.
  • N₂ is practically an inert gas, so plants cannot capture it from the atmosphere. Only some bacteria in the soil and others, which are symbionts of the roots of legumes, are capable of capturing it and taking advantage of it to synthesize proteins.
• Compounds: when molecules are made up of atoms of different elements, such as water (H₂O). Compound immediate principles can be:
  • Inorganic. For example, water, mineral salts (carbonates, phosphates, etc.) and carbon dioxide (CO₂).
  • Organic Made up mainly of carbon and hydrogen, such as carbohydrates, lipids, proteins, and nucleic acids.

via Gfycat

The immediate principles may have different functions:

• Structural function, such as proteins and mineral salts in bones, or lipids in plasma membranes.
• Energy function, such as lipids.
• Biocatalyst function, that is, accelerator of biochemical reactions, such as enzymatic proteins.

The water and mineral salts are discussed below, as well as the properties of true solutions and colloidal dispersions. Carbohydrates, lipids, proteins, and nucleic acids are covered in the following topics.