Transformation of energy in organisms

Living organisms continually require uptake of the energy they obtain from the cleavage of organic substances. The acquisition of energy cannot be considered as its production, but rather as its transformation into a form that the organism can use.

According to the First Thermodynamic Law, energy cannot be lost or generated, nor can it be created or ceased. It is only possible to transform it from one form of energy and another. Part of the energy can thus be released as heat (unable to do the job). The rest of the energy can do the job in the body. The energy of organic substances in animal cells is converted to ATP – the so-called universal energy carrier.

The animal organism (including man) receives energy preferentially by digesting carbohydrates (60%), fats (about 25% and even more in the case of carbohydrate deficiency) and proteins (about 15%). This energy is released in catabolic processes of oxidation processes. Fats may be lacking in the diet for a short time (but not in the long term – due to the solubility of vitamins).