Function of the mitochondria
In eukaryotic cells, mitochondria are organelles whose main function is the synthesis of cellular energy necessary for the metabolic functions of organisms.
In the mitochondria, specifically in the mitochondrial matrix, most of the 4 steps of cellular respiration take place. This is important, since it will generate ATP or cellular energy to carry out metabolic activities.
The functions of mitochondria in organisms can be summarized as: energy production, temperature regulator, cell cycle control (apoptosis), calcium storage, and sex hormone regulation.
Energy production is the most important function of the mitochondria. Energy in the form of adenosine triphosphate (ATP) results from cellular respiration, the 4-step process of which occurs largely in the mitochondria.
Cellular respiration is where cells obtain the nuclear energy necessary to carry out their metabolic functions. Cellular respiration consists of 4 steps:
- Glycolysis: this step occurs in the cytosol of the cell but it is essential as it will generate glucose and the 2 pyruvates for the following stages.
- Pyruvate oxidation: this process occurs in the mitochondrial matrix and transforms pyruvate into acetyl-CoA, an element that will initiate the following process.
- Krebs cycle: also known as the nitric acid cycle, thanks to this process, all 24 of the 38 theoretical ATPs that result from cellular respiration will be synthesized. The Krebs cycle occurs in the same way in the mitochondrial matrix.
- Oxidative phosphorylation: in this step, the NADH and FADH2 obtained from the previous phases will be transformed into ATP thanks to the movement of electrons through a series of proteins embedded in the inner membrane of the mitochondria.
Mitochondria generate heat that will maintain and regulate the temperature of living organisms, especially mammals.
Cell cycle control
Known as apoptosis, the mitochondria have the power to program or initiate the process of cell death. In this way, it controls the growth, development and the end of the cell's life cycle, also known as the cell cycle.
Mitochondria regulate cell biochemistry by storing and regulating the amount of calcium ions. This function is important, as it helps muscle contraction, the release of neurotransmitters and the maintenance of bone health.
Regulation of sex hormones
The mitochondria regulate the production of estrogen and testosterone. Mitochondria, having their own DNA (mitochondrial DNA), can replicate if the cell needs more energy and in turn will reproduce a copy of the information of the sex hormones mentioned during their cell division.