• Renu Joshi, Ph. D.

Functions of Mitochondria

Updated: Apr 6, 2018



The functions of Mitochondria make them called as the power house of cells for their important contribution that is complex, yet essential for the functioning of the organisms. These organelles are found in cytoplasm within the cells and have two, external and internal with deep inner folds. The interior liner is impermeable to many molecules and encloses an area which comprises the matrix of mitochondria. Mitochondria generate power by breaking the nutrients and producing energy from them. The matrix (viscous space within the inner layer) plays a fundamental role in energy generation since it is where the Krebs or citric acid cycle occurs. The matrix is a viscous and dense matter, containing includes ribosomes and mitochondrial deoxyribonucleic acid (DNA). In the citric acid cycle, mitochondria create energy for the movement by breaking down nutrients based on food to high energy molecule called adenosine triphosphate, or ATP.



Citric acid cycle with aconitate

(from Wikimedia Commons, licensed to reproduce under GNU Free Documentation License)


The first step in the cell's metabolic process occurs in the cytosol, where sugar derived nutrients are converted into pyruvate molecules which is then hauled into the mitochondrial matrix. The mitochondrial matrix includes the enzymes and compounds of the citric acid cycle, that's the first stage of mitochondrial energy generation. Pyruvate is oxidized to acetyl coenzyme (CoA) also enters the uric acid cycle and is metabolized to CO2, NADH (Nicotinamide adenine dinucleotide, a dinucleotide coenzyme) and FADH2 (Flavin adenine dinucleotide, a prosthetic protein group). Fatty acids can also be transported from the cell's cytosol into of the mitochondrial matrix and, after oxidation to acetyl CoA, they enter the uric acid. NADH and FADH2 are subsequently used by the electron transfer system, embedded in the interior bronchial, to create ATP for the cell's needs.


The matrix also includes mitochondrial DNA, that makes mitochondria partially autonomous. Mitochondrial DNA is circular like bacteria DNA. A lot of the proteins necessary to the structure and replication of mitochondria and for the enzymes in energy generation are not encoded by mitochondrial DNA, but by genes in of the nucleus. Mutations in mitochondrial genes might lead to a wide range of disorders and diseases, like Leber's hereditary optic neuropathy (LHON), which leads to human blindness. Very significantly, the mitochondrial matrix includes all the machinery required to interpret all of the genes in of the mitochondrial genome in functional proteins.


Translation of genetic substance can be carried out on granules, or ribosomal complexes of transfer RNA (tRNA), as well as ribosomal RNA (rRNA). These RNAs use a somewhat different genetic code from cytoplasmic RNAs. Mitochondrial DNA encodes only around 22 (tRNA) species, but these are of the only RNAs which may interpret mitochondrial messenger RNA (mRNA) into proteins. The vast majority of proteins found in of the mitochondrial matrix are not based out of mitochondrial genes but in the nuclear genes. Then the proteins are transported out of the cell's cytoplasm across of the outer and internal membranes to the matrix.


Renu Joshi, Ph. D.

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