A power house is an installation where energy in the form of electrical power is generated for distribution.
The cells in our body also have energy producing powerhouses. Each cell contains not just one but many of these powerhouse organelles. The number and size of these organelles varies from cell to cell depending on the cell's functions. For instance, muscle cells need a lot of energy, and have 1000s of them per cell.Whereas each skin cell has just a few 100 of them.
These powerhouse organelles go by the name 'mitochondria'
Energy is released by the cell's powerhouse-mitochondria in the form of ATP(adenosine triphosphate). This energy (ATP) is extracted through the metabolism of food by a process called cellular respiration.
The process of cellular respiration consists of four distinct stages, namely (1)Glycolysis (2)Pyruvate oxidation (3)Citric acid cycle, and (4)Oxidative phosphorylation i.e., the electron transport chain
Of these 4 stages, glycolysis occurs in the cell cytoplasm whereas the other 3 stages happen in different areas of the mitochondria of the cell.
In total, 38 molecules of ATP are produced during the whole process of cellular respiration. A majority of this ATP production, 36 to be specific, occurs in the mitochondria of the cell.
Without the mitochondria, cells would be unable to extract energy (ATP) from the nutrients, and all cellular functions would cease.
Other facts to know about the mitochondria:-
The cells in our body also have energy producing powerhouses. Each cell contains not just one but many of these powerhouse organelles. The number and size of these organelles varies from cell to cell depending on the cell's functions. For instance, muscle cells need a lot of energy, and have 1000s of them per cell.Whereas each skin cell has just a few 100 of them.
These powerhouse organelles go by the name 'mitochondria'
Energy is released by the cell's powerhouse-mitochondria in the form of ATP(adenosine triphosphate). This energy (ATP) is extracted through the metabolism of food by a process called cellular respiration.
The process of cellular respiration consists of four distinct stages, namely (1)Glycolysis (2)Pyruvate oxidation (3)Citric acid cycle, and (4)Oxidative phosphorylation i.e., the electron transport chain
Of these 4 stages, glycolysis occurs in the cell cytoplasm whereas the other 3 stages happen in different areas of the mitochondria of the cell.
In total, 38 molecules of ATP are produced during the whole process of cellular respiration. A majority of this ATP production, 36 to be specific, occurs in the mitochondria of the cell.
Without the mitochondria, cells would be unable to extract energy (ATP) from the nutrients, and all cellular functions would cease.
Structure of the mitochondria &
location of enzymes responsible for cellular respiration:
The basic structure of the mitochondrion is composed mainly of two lipid bilayer–protein membranes: an outer membrane and an inner membrane.(click for fig)
Many infoldings of the inner membrane form shelves onto which oxidative enzymes are attached.(click for fig)
In addition, the inner cavity of the mitochondrion is filled with a matrix that contains large quantities of dissolved enzymes that are necessary for extracting energy from nutrients.(click for fig)
The enzymes in the matrix operate in association with the oxidative enzymes on the shelves to cause oxidation of the nutrients, thereby forming carbon dioxide and water and at the same time releasing energy in the form of ATP. (click for video explanation)
Interesting facts about the mitochondria:
- Mitochondria are self-replicative, which means that one mitochondrion can form a second one, a third one, and so on, whenever there is a need in the cell for increased amounts of ATP.
- The mitochondria contain DNA similar to that found in the cell nucleus. DNA is the basic chemical of the nucleus that controls replication of the cell. The DNA of the mitochondrion plays a similar role, controlling replication of the mitochondrion.
- As zygote mitochondria are derived from the ovum, the inheritance of mitochondrial DNA is maternal. This maternal inheritance has been used as a tool to track evolutionary descent.
- Mitochondria have an ineffective DNA repair system, and the mutation rate for mitochondrial DNA is over 10 times the rate for nuclear DNA. A large number of relatively rare diseases,mainly disorders causing defective energy production in tissues with high metabolic rates have now been traced to mutations in mitochondrial DNA .
Other facts to know about the mitochondria:-
- Mitochondria are present in all areas of each cell’s cytoplasm.
- They are concentrated in those portions of the cell that are responsible for the major share of its energy metabolism.
- They are variable in size and shape. Some are only a few hundred nanometers in diameter and globular in shape, whereas others are elongated—as large as 1 micrometer in diameter and 7 micrometers long; still others are branching and filamentous.
Useful link: Khan academy_Steps of cellular respiration
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