The following occurs within the mitochondria: <\/p>\n\n\n\n
- Citric acid cycle<\/li>
- ATP production<\/li><\/ul>\n\n\n\n
Stems from the prokaryotic ancestors resulted in a double layer of membrane and circular DNA (mtDNA)<\/div><\/p>\n\n\n\n
\n\n\n\nStructure of the mitochondria<\/h2>\n<\/span>\n\n\n
The mitochondria are composed of the following components:<\/p>\n\n\n\n
- A<\/strong> double layer of a phospholipid membrane <\/strong>forming two compartments with<\/li>
- an inner matrix<\/strong> and <\/li>
- an intermembrane space<\/strong>, serving for the separation of the biochemical processes.<\/li><\/ol>\n\n\n\n
Within the inner matrix, internal invaginations of the inner membrane form <\/p>\n\n\n\n4. cristae<\/strong>, which increase the surface area; <\/p>\n\n\n\n
within the inner membrane, you will find the<\/p>\n\n\n\n
5. terminal oxidation relating protein complexes<\/strong> (Fe-S-cluster proteins containing metals) and the ATP synthase<\/strong> (F0<\/sub>F1<\/sub>) (Figure 1<\/strong>).<\/p>\n\n\n<\/span>\n
Functions and related metabolic processes<\/h2>\n<\/span>\n\n\n
The primary role of the mitochondria is the production of ATP<\/strong>, the source of energy. But that\u2019s not the only thing that happens within there. <\/p>\n\n\n\n
- DNA and protein synthesis<\/strong><\/li>
- elongation and degradation of fatty acids<\/strong><\/li>
- transportation of proteins<\/strong> and <\/li>
- the fatty acid degradation<\/strong><\/li><\/ul>\n\n\n\n
![\"\"](\"https:\/\/meddists.com\/learn\/wp-content\/uploads\/2021\/09\/Mito-1-1024x540.png\")
<\/a>Figure 1. The features of the mitochondria<\/strong><\/figcaption><\/figure><\/div>\n\n\n<\/span>\n Production of ATP – terminal oxidation and electron transport<\/h2>\n<\/span>\n\n\n
In the terminal oxidation\/electron transport chain, electron transmission is accompanied by a proton gradient<\/strong> between the two sides of the inner membrane. The formation of the proton gradient occurs through the complexes of the respiratory chain (ETC).<\/em><\/p>\n\n\n\n
- Complex I.<\/strong> is responsible for the oxidation of the NADH, while electrons are released into the membrane and the protons are pumped into the intermembrane space.<\/li>
- Complex II.<\/strong> is not a transmembrane protein, thus it can not pump out hydrogen. The produced hydrogen from the succinate-fumarate change should be transported to the next transmembrane proteins, complex III.<\/li>
- Ubiquinone<\/strong> (UQ) is a kind of “postman” transporting the protons and electrons towards the next complex. When the UQ is fully equipped carries 2 protons and 2 electrons.<\/li>
- Complex III.<\/strong> pumping out protons respectively, while electrons are travelling via membrane to the next complex.<\/li>
- Complex IV.<\/strong> is responsible for the electron “sleigh ride” into the matrix.<\/li>
- Proton gradients are formed because the inner membrane is impermeable to protons. Protons return to the matrix through the proton channel, which is part of the ATP synthase<\/strong> (Complex V<\/strong>), a multi-subunit enzyme. The enzyme consists of F0<\/sub>F1<\/sub> subunits. F0<\/sub>\u00a0forms the proton channel, and F1<\/sub>\u00a0performs ATP synthesis (Figure 2<\/strong>).<\/li><\/ol>\n\n\n\n
The difference in the concentration of the protons leads to a pH difference, i.e., the matrix is more alkaline than the membrane. Thus, the proton motive force is formed, so the free energy reduction is converted into electrochemical energy<\/em>.<\/p>\n\n\n\n
The protons spontaneously return to the matrix according to the electrochemical gradient, which results in a reduction in free energy and is transformed by ADP phosphorylation into chemical energy in the form of ATP.<\/em><\/p>\n\n\n\n
![\"\"](\"https:\/\/meddists.com\/learn\/wp-content\/uploads\/2021\/09\/Mito2-1-1024x619.png\")
<\/a>Figure 2. Proton gradient of the ETC, generation of ATP<\/strong><\/figcaption><\/figure><\/div>\n\n\n\n The energy generated during the back oxidation of reduced coenzymes is used for the ATP synthesis from oxidative phosphorylation complexes from ADP and inorganic phosphate. <\/em><\/p>\n\n\n<\/span>\n
Inhibition of the complexes<\/h2>\n<\/span>\n\n\n
Inhibiting the respiratory complexes lead to the lack of or less ATP production (Table 1). <\/p>\n\n\n\n
Compound<\/th> Effects<\/th><\/tr><\/thead> Carbon dioxide (CO)<\/strong><\/td> Inhibiting cytochrome oxidase (Complex IV<\/strong>)<\/td><\/tr> Cyanide (CN–<\/sup>)<\/strong><\/td> Inhibiting cytochrome oxidase (Complex IV<\/strong>) <\/td><\/tr> Antimycin A<\/strong><\/td> Inhibits the electron transition from Cyt b and Cyt c1 (Complex III<\/strong>)<\/td><\/tr> Malonate <\/strong><\/td> Competitive inhibitor of Succinate dehydrogenase (Complex II<\/strong>)<\/td><\/tr> Rotenone<\/strong><\/td> Inhibits the electron transfer from the Fe-S centre to the UQ (Complex I<\/strong>)<\/td><\/tr> Oligomycin<\/strong><\/td> Specific inhibitors of the ATP synthase (Complex V<\/strong>)<\/td><\/tr> Dinitrophenol (DNP)<\/strong><\/td> Protonophore uncoupleing agent<\/td><\/tr> Thermogenin\/ Uncoupling protein 1 (UCP-1)<\/strong><\/td> Forms proton-conducting pore, no ATP is produced (a feature of brown adipocytes – heat production UCP1 \u2014 Thermogenin<\/a>)<\/td><\/tr> Atractyloside<\/strong><\/td> Inhibits adenine nucleotide exchange (ATP-ADP)<\/td><\/tr><\/tbody><\/table> Table 1. Effects of ETC inhibitors<\/strong><\/figcaption><\/figure>\n\n\n\n <\/p>\n\n\n\n
There are several chemical agents capable to block\/alter different parts of the chain (Figure 3-4).<\/p>\n\n\n\n
- Complex II.<\/strong> is not a transmembrane protein, thus it can not pump out hydrogen. The produced hydrogen from the succinate-fumarate change should be transported to the next transmembrane proteins, complex III.<\/li>
- elongation and degradation of fatty acids<\/strong><\/li>
- an inner matrix<\/strong> and <\/li>
- A<\/strong> double layer of a phospholipid membrane <\/strong>forming two compartments with<\/li>
![\"\"](\"https:\/\/meddists.com\/learn\/wp-content\/uploads\/2021\/09\/Mito-1.png\")
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