Related topics: cells · protein · cell death · neurons · brain

The energetic origins of life

( —Imagination is perhaps the most powerful tool we have for creating the future. The same might be said when it comes to creating the past, especially as it pertains to origin of life. Under what conditions did ...

Why do we still have mitochondrial DNA?

The mitochondrion isn't the bacterium it was in its prime, say two billion years ago. Since getting consumed by our common single-celled ancestor the "energy powerhouse" organelle has lost most of its 2,000+ genes, likely ...

Mitochondria and the art of DNA maintenance

Humans have 46 chromosomes, and each one is capped at either end by repetitive sequences called telomeres. If you ask a biologist if humans have circular DNA, they are likely to say 'no.' That is because eukaryotic cell nuclei ...

The vital question: Why is life the way it is?

The Vital Question: Why is life the way it is? is a new book by Nick Lane that is due out on April 23rd. His question is not one for a static answer but rather one for a series of ever sharper explanations—explanations ...

Do our mitochondria run at 50 degrees C?

Our body temperature is held at a fairly steady 37.5°C, and the assumption has always been that most of our physiological processes take place at this temperature. The heat needed to maintain this temperature in the face ...

Brain tumor cells decimated by mitochondrial 'smart bomb'

An experimental drug that attacks brain tumor tissue by crippling the cells' energy source called the mitochondria has passed early tests in animal models and human tissue cultures, say Houston Methodist scientists.

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In cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed organelle found in most eukaryotic cells. These organelles range from 0.5–10 micrometers (μm) in diameter. Mitochondria are sometimes described as "cellular power plants" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in a range of other processes, such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth. Mitochondria have been implicated in several human diseases, including mitochondrial disorders and cardiac dysfunction, and may play a role in the aging process. The word mitochondrion comes from the Greek μίτος or mitos, thread + χονδρίον or khondrion, granule.

Several characteristics make mitochondria unique. The number of mitochondria in a cell varies widely by organism and tissue type. Many cells have only a single mitochondrion, whereas others can contain several thousand mitochondria. The organelle is composed of compartments that carry out specialized functions. These compartments or regions include the outer membrane, the intermembrane space, the inner membrane, and the cristae and matrix. Mitochondrial proteins vary depending on the tissue and the species. In humans, 615 distinct types of proteins have been identified from cardiac mitochondria; whereas in Murinae (rats), 940 proteins encoded by distinct genes have been reported. The mitochondrial proteome is thought to be dynamically regulated. Although most of a cell's DNA is contained in the cell nucleus, the mitochondrion has its own independent genome. Further, its DNA shows substantial similarity to bacterial genomes.

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