Energy Balance | Cellular respiration in humans

Energy Balance

The energy balance of cellular respiration in the case of glucose can be summarized by the formation of 32 ATP molecules per glucose: C6H12O6 + 6 O2 become 6 CO2 + 6 H2O + 32 ATP (for the sake of clarity the ADP and the phosphate residue Pi were omitted in the educts). Under anaerobic conditions, i.e. oxygen deficiency, the citrate cycle cannot take place and energy can only be obtained via aerobic glycolysis: C6H12O6 + 2 Pi + 2 ADP become 2 lactate + 2 ATP + 2 H2O. Thus, only 6% of the energy is obtained per glucose molecule, as would be the case with aerobic glycolysis.

Diseases related to cellular respiration

Cellular respiration is essential for survival, i.e. many mutations in the genes that code for the proteins involved in cellular respiration, such as glycolysis enzymes, are lethal. Nevertheless, genetic diseases of cellular respiration do occur. These can have their origin both in nuclear DNA and in mitochondrial DNA.

The mitochondria themselves contain their own genetic material, which is necessary for cell respiration. However, these diseases show a similar symptomatology, as they all have in common that they interfere with and disrupt cell respiration. Diseases of cell respiration often show similar clinical pictures.

In particular, there are disturbances of tissues that need a lot of energy. These include especially the nerve, muscle, heart, kidney and liver cells.Therefore, symptoms such as muscle weakness or signs of brain damage often occur at a young age, if not at birth. Furthermore, a pronounced lactic acidosis (an overacidification of the body with lactate, which accumulates because pyruvate cannot be sufficiently broken down in the citrate cycle) also speaks for itself.

It can also lead to malfunctioning of the internal organs. The diagnosis and therapy of cell respiration diseases should be carried out by specialists, as the clinical picture can be very diverse and different. The current state of affairs is that there is no causal and curative therapy yet.

The diseases can only be treated symptomatically. Since mitochondrial DNA is passed on from mother to children in a very complicated way, women who suffer from a cellular respiratory disease should consult a specialist if they wish to have children, since only a specialist can approximately estimate the probability of inheritance.