Education
- What Is Insulin?
Insulin is a hormone. It works as a chemical messenger that helps your body use the glucose in your blood to give you energy. You can think of it as the key that unlocks the door to the body’s cells. Once the door is unlocked, glucose can enter the...
- Exceptions To Vsepr Theory
Valence Shell Electron Pair Repulsion theory does not always predict the correct geometry of molecules. Examples of exceptions include: transition metal molecules (e.g., CrO3 is trigonal bipyramidal, TiCl4 is tetrahedral)odd-electron molecules (CH3 is...
- Mitochondria In Details
Fig: Ultrastructure of Mitochondria Mitochondria was first discovered by Koliker.According to him Mitochondria is made up of mitos & chondrian. Here mitos means thread & chondrian...
- Discovery Of Sickle Cell Anemia
An American doctor, R. Lebby, wrote the first modern description of sickle cell anemia in 1846 in an article titled ‘Case of Absence of the Spleen.’ The next published reports of sickle cell disease were in African medical articles. These articles...
- Nanotechnology
In 1965, Gordon Moore, one of the founders of Intel Corporation, made the outstanding prediction that the number of transistors that could be fit in a given area would double every 18 months for the next ten years. In 1959, theoretical physicist Richard...
Education
Mitochondrion
The mitochondrion (plural mitochondria) is a membrane-enclosed structure found in most eukaryotic cells (the cells that make up plants, animals, fungi, and many other forms of life).[1] Mitochondria range from 0.5 to 1.0 micrometer (μm) in diameter. These organelles 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.[2] In addition to supplying cellular energy, mitochondria are involved in other tasks such as signaling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth.[3] Mitochondria have been implicated in several human diseases, including mitochondrial disorders[4] and cardiac dysfunction,[5] and may play a role in the aging process. The word mitochondrion comes from the Greek μίτος, mitos, i.e. "thread", and χονδρίον, chondrion, i.e. "granule".[6]
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.[7][8] 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,[9] whereas in rats, 940 proteins have been reported.[10] The mitochondrial proteome is thought to be dynamically regulated.[11] 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.[12]
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.[7][8] 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,[9] whereas in rats, 940 proteins have been reported.[10] The mitochondrial proteome is thought to be dynamically regulated.[11] 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.[12]
Structure
Mitochondria are present in both plant and animal cells. They are rod-shaped structures that are enclosed within two membranes - the outer membrane and the inner membrane. The membranes are made up of phospholipids and proteins.
The space in between the two membranes is called the inter-membrane space which has the same composition as the cytoplasm of the cell. However, the protein content in this space differs from that in the cytoplasm. The structure of the various components of mitochondria are as follows:
* Outer Membrane
The outer membrane is smooth unlike the inner membrane and has almost the same amount of phospholipids as proteins. It has a large number of special proteins called porins, that allow molecules of 5000 daltons or less in weight to pass through it. The outer membrane is completely permeable to nutrient molecules, ions, ATP and ADP molecules.
* Inner Membrane
The inner membrane is more complex in structure than the outer membrane as it contains the complexes of the electron transport chain and the ATP synthetase complex. It is permeable only to oxygen, carbon dioxide and water. It is made up of a large number of proteins that play an important role in producing ATP, and also helps in regulating transfer of metabolites across the membrane. The inner membrane has infoldings called the cristae that increase the surface area for the complexes and proteins that aid in the production of ATP, the energy rich molecules.
* Matrix
The matrix is a complex mixture of enzymes that are important for the synthesis of ATP molecules, special mitochondrial ribosomes, tRNAs and the mitochondrial DNA. Besides these, it has oxygen, carbon dioxide and other recyclable intermediates.
Although most of the genetic material of a cell is contained within the nucleus, the mitochondria have their own DNA. They have their own machinery for protein synthesis and reproduce by the process of fission like bacteria do. Due to their independence from the nuclear DNA and similarities with bacteria, it is believed that mitochondria have originated from bacteria by endosymbiosis. Given below is an illustrated diagram of the structure of mitochondria.
Mitochondria
Functions
Functions of mitochondria vary according to the cell type in which they are present.
* The most important function of the mitochondria is to produce energy. The food that we eat is broken into simpler molecules like carbohydrates, fats, etc., in our bodies. These are sent to the mitochondrion where they are further processed to produce charged molecules that combine with oxygen and produce ATP molecules. This entire process is known as oxidative phosphorylation.
* It is important to maintain proper concentration of calcium ions within the various compartments of the cell. Mitochondria help the cells to achieve this goal by serving as storage tanks of calcium ions.
* They also help in the building of certain parts of the blood, and hormones like testosterone and estrogen.
* Mitochondria in the liver cells have enzymes that detoxify ammonia.
* They play an important role in the process of programmed cell death. Unwanted and excess cells are pruned away during the development of an organism. The process is known as apoptosis. Abnormal cell death due to mitochondrial dysfunction can affect the function of the organ.
The space in between the two membranes is called the inter-membrane space which has the same composition as the cytoplasm of the cell. However, the protein content in this space differs from that in the cytoplasm. The structure of the various components of mitochondria are as follows:
* Outer Membrane
The outer membrane is smooth unlike the inner membrane and has almost the same amount of phospholipids as proteins. It has a large number of special proteins called porins, that allow molecules of 5000 daltons or less in weight to pass through it. The outer membrane is completely permeable to nutrient molecules, ions, ATP and ADP molecules.
* Inner Membrane
The inner membrane is more complex in structure than the outer membrane as it contains the complexes of the electron transport chain and the ATP synthetase complex. It is permeable only to oxygen, carbon dioxide and water. It is made up of a large number of proteins that play an important role in producing ATP, and also helps in regulating transfer of metabolites across the membrane. The inner membrane has infoldings called the cristae that increase the surface area for the complexes and proteins that aid in the production of ATP, the energy rich molecules.
* Matrix
The matrix is a complex mixture of enzymes that are important for the synthesis of ATP molecules, special mitochondrial ribosomes, tRNAs and the mitochondrial DNA. Besides these, it has oxygen, carbon dioxide and other recyclable intermediates.
Although most of the genetic material of a cell is contained within the nucleus, the mitochondria have their own DNA. They have their own machinery for protein synthesis and reproduce by the process of fission like bacteria do. Due to their independence from the nuclear DNA and similarities with bacteria, it is believed that mitochondria have originated from bacteria by endosymbiosis. Given below is an illustrated diagram of the structure of mitochondria.
Mitochondria
Functions
Functions of mitochondria vary according to the cell type in which they are present.
* The most important function of the mitochondria is to produce energy. The food that we eat is broken into simpler molecules like carbohydrates, fats, etc., in our bodies. These are sent to the mitochondrion where they are further processed to produce charged molecules that combine with oxygen and produce ATP molecules. This entire process is known as oxidative phosphorylation.
* It is important to maintain proper concentration of calcium ions within the various compartments of the cell. Mitochondria help the cells to achieve this goal by serving as storage tanks of calcium ions.
* They also help in the building of certain parts of the blood, and hormones like testosterone and estrogen.
* Mitochondria in the liver cells have enzymes that detoxify ammonia.
* They play an important role in the process of programmed cell death. Unwanted and excess cells are pruned away during the development of an organism. The process is known as apoptosis. Abnormal cell death due to mitochondrial dysfunction can affect the function of the organ.
- What Is Insulin?
Insulin is a hormone. It works as a chemical messenger that helps your body use the glucose in your blood to give you energy. You can think of it as the key that unlocks the door to the body’s cells. Once the door is unlocked, glucose can enter the...
- Exceptions To Vsepr Theory
Valence Shell Electron Pair Repulsion theory does not always predict the correct geometry of molecules. Examples of exceptions include: transition metal molecules (e.g., CrO3 is trigonal bipyramidal, TiCl4 is tetrahedral)odd-electron molecules (CH3 is...
- Mitochondria In Details
Fig: Ultrastructure of Mitochondria Mitochondria was first discovered by Koliker.According to him Mitochondria is made up of mitos & chondrian. Here mitos means thread & chondrian...
- Discovery Of Sickle Cell Anemia
An American doctor, R. Lebby, wrote the first modern description of sickle cell anemia in 1846 in an article titled ‘Case of Absence of the Spleen.’ The next published reports of sickle cell disease were in African medical articles. These articles...
- Nanotechnology
In 1965, Gordon Moore, one of the founders of Intel Corporation, made the outstanding prediction that the number of transistors that could be fit in a given area would double every 18 months for the next ten years. In 1959, theoretical physicist Richard...