By Mary Anne Winslow
In the following article, I am going to give you explanation and description of mitochondria, followed by giving the concise narration of how mitochondrion first was tracked. After that I will explain the formation of the mitochondria and how it is connected to its function.
The definition of mitochondria is to convert the chemical energy of fuel molecules stored in the bonds of carbohydrates, into a form that the cell can use, for essential biochemical conversions of amino acids and fatty acids, and the energy rich molecule called ATP (adenosine triphosphate). Present day mitochondria probably evolved as a consequence of early end symbiosis. The idea of the endosymbiosis theory was first originated by the early 20th century Russian Biologist. Symbiosis is the close relationship between organisms of different species that live together. Mitochondria evolved by a symbiosis, where one species of prokaryote was engulfed by and lived inside another species of prokaryote. The engulfed prokaryotes provided hosts with certain advantages associated with their specific metabolic abilities. Mitochondria are thought to have originated as bacteria capable of carrying out oxidative metabolism.
Mitochondria are described as bacteria- like elements with a double membrane. Typical mitochondria are small and somewhat less than 1.5 m in diameter and 2-8m in length- about the size of many bacteria.
The number of mitochondria within a cell depends on the cell’s level of metabolic activity. An average human liver cell contains more than a thousand mitochondria. Cells that require the most chemical energy tend to have the most mitochondria per unit of volume. Mitochondria are tubular shaped organelles and are found in all eukaryotic cells. Two membranes enclose the mitochondria, each a phospholipids bilayer with a unique collection of embedded proteins. The outer membrane is smooth and protective; it offers little resistance to movement of substances into and out of the mitochondrion.
The inner mitochondria membrane contains many large protein molecules that participate in cellular respiration and the production of ATP. The inner membrane exerts much more control over what enters and leaves the mitochondrion than does the outer membrane. The region enclosed by the inner membrane is referred to as the mitochondrial matrix. In addition to many proteins, the matrix contains some ribosome and DNA that are used to make some of the proteins needed for cellular respiration. The aristae give inner mitochondrial membrane a large surface area, and this enhances productivity of cellular respiration.
Mitochondria have their own DNA and the DNA contains several genes that produce proteins, essential to the mitochondrion’s role in oxidative metabolism. All the genes copied into RNA are used to make proteins within the mitochondrion. A eukaryotic cell does not produce brand new mitochondria each time the cell divides. Mitochondria divide into two themselves, doubling in number and then these are partitioned between new cells.
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