Mitochondria adenosine triphosphates

MITOCHONDRION A membrane-bound organelle of eukaryotic organisms that replicates independently of the cell nucleus and contains its own ENA and its own protein-synthesizing apparatus its function is to provide energy to the cell in the form of adenosine triphosphate by oxidative phosphorylation. 

Figure 1.4 Compaitmentation of biosynthesis and sequestration. Abbreviations SM, secondary metabolites CS-SM, conjugate of SM with glutathione NPAAs, non-protein amino acids ATP, adenosine triphosphate ADP, adenosine diphosphate mt, mitochondrion cp, chloroplast nc, nucleus 1, passive transport 2, free diffusion 3, H+/SM antiporter 4, ABC transporter for SM conjugated with glutathione 5, ABC transporter for free SM 6, H+-ATPase. (See Plate 3 in colour plate section.)...

Glycolysis The biochemical process by which glucose is converted to pyruvate in the cytosol of the cell. It results in the production of 2 mol of adenosine triphosphate (ATP) and 2 mol of the reduced cofactor nicotinamide adenine dinucleotide (NADH), which transfers its reducing equivalents to the mitochondrion for the production of ATP via oxidative phosphorylation. 

Oxidative phosphorylation The process by which adenosine triphosphate (ATP) is synthesized from a hydrogen ion gradient across the mitochondrial inner membrane. The hydrogen ion gradient is formed by the action of protein complexes in the mitochondrial membrane that sequentially transfer electrons from the rednced cofactors nicotinamide adenine dinucleotide (NADH) and FADH to molecnlar oxygen. Movement of hydrogen ions back into the mitochondrion via ATP synthase drives the synthesis of ATP. 

Fish swim, birds fly, babies crawl. Enzymes, too, are constantly on the move. The world s smallest motor, in fact, is an enzyme found in the powerhouse of the cell (the mitochondrion) which generates energy in the form of a molecule called adenosine triphosphate, or ATR Often dubbed the energy currency of life,... 

Figure 2. Cycles of life and death. A brief overview showing how paraquat (and similarly diquat) interacts with two of the most fundamental processes of life photosynthesis in the chloroplast and respiration in the mitochondrion. Abbreviations ADP, adenosine diphosphate ATP, adenosine triphosphate e, electron proton NAD and NADH, oxidised and reduced forms of nicotinamide adenine dinucleotide NADP and NADPH, oxidised and reduced forms of nicotinamide adenine dinucleotide phosphate Paraquat, paraquat radical Pi, inorganic phosphate superoxide radical.

Mitochondria (singular = mitochondrion) are the so-called "power plants" of eukaryotic cells because they are the major source of energy for these cells under aerobic conditions (when oxygen is present). Mitochondria are the sites where complex processes involved in energy generation (such as electron transport and oxidative phosphorylation) are found. The product of mitochondrial action is chemical energy stored in the form of adenosine triphosphate, more commonly called ATP. 

Many particles pass through the membrane of a cell with the electrochemical energy gradient, but some against it. Adenosin triphosphate (ATP) is thought to provide the energy for this latter occurrence. An important biochemical reaction is, then, the endothermic formation of ATP by the phosphorylation process. The enzymes which are associated with this are found in the subcellular unit known as the mitochondrion. Electrochemical reactions may function here. 

Carnitine serves as a cofactor for several enzymes, including carnitine translo-case and acyl carnitine transferases I and II, which are essential for the movement of activated long-chain fatty acids from the cytoplasm into the mitochondria (Figure 11.2). The translocation of fatty acids (FAs) is critical for the genaation of adenosine triphosphate (ATP) within skeletal muscle, via 3-oxidation. These activated FAs become esterified to acylcamitines with carnitine via camitine-acyl-transferase I (CAT I) in the outer mitochondrial membrane. Acylcamitines can easily permeate the membrane of the mitochondria and are translocated across the membrane by carnitine translocase. Carnitine s actions are not yet complete because the mitochondrion has two membranes to cross thus, through the action of CAT II, the acylcar-nitines are converted back to acyl-CoA and carnitine. Acyl-CoA can be used to generate ATP via 3-oxidation, Krebs cycle, and the electron transport chain. Carnitine is recycled to the cytoplasm for fumre use. 

---