submit urlsubmit rss feedadd directoryphysician directoryDirectory of Mobile Health Sites

article

In cell biology, a mitochondrion (plural mitochondria) (from Greek mitos thread + khondrion granule) is an organelle, variants of which are found in most eukaryotic cells. Mitochondria are sometimes described as "cellular power plants," because they convert organic materials into energy in the form of ATP via the process of oxidative phosphorylation. Usually a cell has hundreds or thousands of mitochondria, which can occupy up to 25% of the cell's cytoplasm. Mitochondria have their own DNA and according to the endosymbiotic theory may have descended from free-living prokaryotes that were closely related to rickettsia bacteria.

Mitochondrion structure


A mitochondrion contains outer and inner membranes composed of phospholipid bilayers and proteins. The two membranes, however, have very different properties. Inside the mitochondria is a compartment called the matrix that contains both proteins and DNA.

The outer membrane

The outer mitochondrial membrane, which encloses the entire organelle, has a protein-to-phospholipid ratio similar to the eucaryotic plasma membrane (about 1:1 by weight). It contains numerous integral proteins called porins, which contain a relatively large internal channel (about 2-3 nm) that is permeable to all molecules of 5000 daltons or less. Larger molecules can only traverse the outer membrane by active transport. It also contains a variety of enzymes involved in such diverse activities as the elongation of fatty acids, oxidation of epinephrine (adrenaline), and the degradation of tryptophan.

The inner membrane

The inner mitochondrial membrane contains proteins with four types of functions:
  1. Those that carry out the oxidation reactions of the respiratory chain.
  2. ATP synthase, which makes ATP in the matrix.
  3. Specific transport proteins that regulate the passage of metabolites into and out of the matrix.
  4. Protein import machinery.
It contains more than 100 different polypeptides, and has a very high protein-to-phospholipid ratio (more than 3:1 by weight, which is about 1 protein for 15 phospholipids). Additionally, the inner membrane is rich in an unusual phospholipid, cardiolipin, which is usually characteristic of bacterial plasma membranes. Unlike the outer membrane, the inner membrane does not contain porins, and is highly impermeable; almost all ions and molecules require special membrane transporters to enter or exit the matrix. In addition, there is a membrane potential across the inner membrane.

More on [ Mitochondrion ]


directory of related categories

 
Mitochondrial RSS feed
Mitochondrial - Twitter Search

Alpha-synuclein overexpression and aggregation exacerbates impairment of mitochondrial functions by augmen...: - http://tinyurl.com/yzen5ym
research_papers (qasim) Fri, 06 Nov 2009 05:30:06 -0000
Alpha-synuclein overexpression and aggregation exacerbates impairment of mitochondrial functions by augmen...: - http://tinyurl.com/yzen5ym
(-)-Epigallocatechin-3-gallate induces apoptosis of human hepatoma cells by mitochondrial pathways related...: - http://tinyurl.com/ykmqldd
research_papers (qasim) Fri, 06 Nov 2009 05:30:00 -0000
(-)-Epigallocatechin-3-gallate induces apoptosis of human hepatoma cells by mitochondrial pathways related...: - http://tinyurl.com/ykmqldd
Glutamine homeostasis and mitochondrial dynamics.: - http://tinyurl.com/ykhgj47
research_papers (qasim) Fri, 06 Nov 2009 05:29:58 -0000
Glutamine homeostasis and mitochondrial dynamics.: - http://tinyurl.com/ykhgj47
"Mitochondrial DNA is well suited to data such as digitized photographs, audio recordings, and crossword puzzles."
ColinPeters (Colin Peters) Fri, 06 Nov 2009 02:30:21 -0000
"Mitochondrial DNA is well suited to data such as digitized photographs, audio recordings, and crossword puzzles."
Friend has mitochondrial disease..DNA malformation causing system dysfunction, muscle pain/spasm/weakness, eyesight problems, etc etc.brutal
1339tlc (TLC) Fri, 06 Nov 2009 01:09:41 -0000
Friend has mitochondrial disease..DNA malformation causing system dysfunction, muscle pain/spasm/weakness, eyesight problems, etc etc.brutal
The mitochondrial theory of aging: insight from transgenic and knockout mouse models. http://bit.ly/4hjyOE
medstudentwiki (KB Watts) Thu, 05 Nov 2009 21:18:12 -0000
The mitochondrial theory of aging: insight from transgenic and knockout mouse models. http://bit.ly/4hjyOE

 
Subscribe to Mitochondrial RSS feed

directory of related sites

Carnitine Palmitoyltransferase Deficiency - Newsletter for health care professionals and patients interested in CPT deficiency, a mitochondrial disorder of fat metabolism that causes muscle breakdown.
Meta Description: [ Newsletter for health care professionals and patients interested in CPT deficiency, a rare genetic disorder of fat metabolism that causes muscle breakdown. ]

Center for Inherited Disorders of Energy Metabolism (CIDEM) - A group of inter-disciplinary, clinical diagnostic laboratories which focus on disorders of mitochondrial function at Case Western Reserve University.

Foundation for a Cure for Mitochondrial Disease, Inc. - Fundraising for a cure for mitochondrial disease such as Melas, Merf, Narp, and Leighs Syndromes.

Mitochondrial Disease in Children - All seven of Kathleen's children have mitochondrial encephalomyopathy, and two of them have hearing loss as a reult.
Meta Description: [ mitochondrial myopathy (disease) information particularly about childrenwith neuromuscular disease ]

Mitochondrial Disorders Foundation of America - Support group for mitochondrial disorders.

Mitochondrial Myopathies - An information sheet compiled by NINDS, the National Institute of Neurological Disorders and Stroke.
Meta Description: [ Mitochondrial myopathies information sheet compiled by the National Institute of Neurological Disorders and Stroke (NINDS). ]

Nijmegen Center for Mitochondrial Disorders - Information about the facility as well as diagnostics and research.
Meta Description: [ Nijmegen Center for Mitochondrial Disorders ]

United Mitochondrial Disease Foundation - To promote research for the cure and treatment, and to provide support to families. The UMDF offers a library, patient registry, support information, conferences, research and grant updates, and a special section for physicians.

Mitochondrial related videos
Jeni Stepanek - Jeni Stepanek Speaks The Truth | The Unreality Show
Next Video
Mitochondrial related videos

 

HOMEADVERTISINGABOUT US

articlesartsbusinesscomputersgameshealthhospitalshomekids & teensnewsmobilephysiciansrecreationreferenceregionalscienceshoppingsocietysportsworld


Submit a Site About Become an Editor