GENERAL MICROBIOLOGY - T.P. Pyrog - 2004

11. FUNDAMENTAL MECHANISMS OF METABOLISM AND ENERGY CONVERSION IN MICROORGANISMS

11.3. THE PRINCIPLE OF "BIOCHEMICAL UNITY"

The principle of "biochemical unity" is one of the few dogmas widely accepted today. According to this principle, All living organisms on Earth share a profound biochemical similarity. This is manifested, for instance, in the identical "building blocks" used by all living things for Cell synthesis, The Role of ATP as a universal carrier of biological energy, the universality of METABOLISM/28.html">The Genetic Code and The Plasma Membrane, as well as the uniformity of sugar conversion pathways and The Nature of the Respiratory Chain. Central Metabolic pathways are nearly identical across all living organisms. Only a few groups of Bacteria exhibit modified core metabolic schemes where certain pathways predominate while others are truncated or otherwise altered. All PATTERNS OF MICROBIAL metabolism can ultimately be reduced to a general framework. Metabolic pathways evidently evolved over time, and it is believed that the biochemical machinery typical of aerobic organisms emerged relatively late, following the accumulation of oxygen in the atmosphere. Today, it remains difficult to determine whether the truncated metabolic pathways found in certain bacteria represent primitive ancestral traits or the result of evolutionary degradation.