What is Mitochondria: Definition and 19 Discussions

A mitochondrion (, plural mitochondria) is a double membrane-bound organelle found in most eukaryotic organisms. Mitochondria generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. Mitochondria were first discovered by Kolliker (1880 CE) in the voluntary muscles of insects. A mitochondrion is nicknamed the powerhouse of the cell, first coined by Philip Siekevitz in a 1957 article of the same name.Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). A number of unicellular organisms, such as microsporidia, parabasalids, and diplomonads, have reduced or transformed their mitochondria into other structures. One eukaryote, Monocercomonoides, is known to have completely lost its mitochondria, and one multicellular organism, Henneguya salminicola, is known to have retained mitochondrion-related organelles in association with a complete loss of their mitochondrial genome.Mitochondria are commonly between 0.75 and 3 μm² in area but they vary considerably in size and structure. Unless specifically stained, they are not visible. In addition to supplying cellular energy, mitochondria are involved in other tasks, such as signaling, cellular differentiation, and cell death, as well as maintaining control of the cell cycle and cell growth. Mitochondrial biogenesis is in turn temporally coordinated with these cellular processes. Mitochondria have been implicated in several human diseases and conditions, such as mitochondrial disorders, cardiac dysfunction, heart failure and autism.The number of mitochondria in a cell can vary widely by organism, tissue, and cell type. A mature red blood cell has no mitochondria, whereas a liver cell can have more than 2000. The mitochondrion is composed of compartments that carry out specialized functions. These compartments or regions include the outer membrane, intermembrane space, inner membrane, cristae and matrix.
Although most of a cell's DNA is contained in the cell nucleus, the mitochondrion has its own genome ("mitogenome") that is substantially similar to bacterial genomes. Mitochondrial proteins (proteins transcribed from mitochondrial DNA) vary depending on the tissue and the species. In humans, 615 distinct types of proteins have been identified from cardiac mitochondria, whereas in rats, 940 proteins have been reported. The mitochondrial proteome is thought to be dynamically regulated.

View More On Wikipedia.org
  1. TytoAlba95

    Biology MCQ- Mitochondria and O2 consumption

    I don't get, how option A corresponds to time point I. Electron transport/flow is independent of the phosphorylation, isn't it? Though it is not independent the other way round, i.e. the setting up of proton gradient requires the electron flow. I think the matching should have been: I-E, II-D...
  2. Zohar

    How many proteins are coded by mitochondrial DNA compared to nuclear DNA?

    The mitochondria has DNA code which being translated to protein in a certain amount. So how many proteins are from the mitochondria compared to the nuclues?
  3. M

    What would this artificial "super" mitochondria be able to do?

    I was reading a science article and it mentioned in the future that scientist could engineer an artificial super mitochondria. The article is here. https://www.hindawi.com/journals/sci/2017/7610414/ I know the mitochondria generates energy and helps with respiration and the brief description...
  4. J

    A physics perspective needed on how the Mitochondria machine works

    I purposely added this post to the general physics thread rather than the biology thread because the solution is probably not in biology. Basically my PhD is in mitochondrial biology. Mitochondria are the energy producing organelles in the body which make energy by adding a chemical bond...
  5. Genava

    Biparental Inheritance of Mitochondrial DNA in Humans

    Paternal transmission of mitochondrial DNA (mtDNA) may be possible, a new study suggests – contradicting the accepted view that it is passed on exclusively through maternal inheritance. The find, made by a team led by Taosheng Huang from Cincinnati Children’s Hospital Medical Centre, and...
  6. Ygggdrasil

    What type of bacteria evolved into mitochondria?

    An important step in the evolution of plants, animals, and other complex, multicellular forms of life was eukaryogenesis, the evolution of eukaryotes. Eukaryotes are one of the three major classifications of life (alongside single-celled bacteria and archaea) and are characterized by cellular...
  7. A

    Validity of respiration measures in isolated mitochondria?

    I've recently read a couple of papers on exercise and mitochondria (see e.g., http://www.sciencedirect.com/science/article/pii/S0891584907008349), in which state 4 and state 3 respiration rates and ROS production are assessed in vitro after exercise has been performed (i.e., rat heart...
  8. Ygggdrasil

    Insights When did Mitochondria Evolve? - Comments

    Ygggdrasil submitted a new PF Insights post https://www.physicsforums.com/insights/when-did-https://www.physicsforums.com/insights/when-did-mitochondria-evolve/-evolve/ https://www.physicsforums.com/insights/when-did-https://www.physicsforums.com/insights/when-did-mitochondria-evolve/-evolve/
  9. caters

    Fastest animals having similar mitochondria

    I have noticed that cheetahs, peregrine falcons, and sailfish have similar mitochondria as far as amount of base pairs, genes, RNAs, and proteins. Cheetahs have in their mitochondria 17,047 base pairs, 13 genes, 24 RNAs, and 13 proteins. Their speed is up to 75 mph with their acceleration being...
  10. B0b-A

    Any evidence bacteria can exist within mitochondria in humans?

    I heard a claim bacteria can exist within human mitochondria, is there any evidence that is true ?. mitochondria"']https://www.google.com/search?q="bacteria+within+mitochondria"[/URL] only gets one hit, and the examples given are not human.
  11. C

    Why mother's DNA and not mitochondria transplanted into egg?

    I am referring to "3 parents baby" discussed e.g. here http://www.economist.com/news/leaders/21565209-new-technique-help-cure-mitochondrial-diseases-should-be-permitted-law-powering . AFAIU they take the egg of mitochondria donor, remove its nucleus / DNA and transplant into it the mother's DNA...
  12. T

    Do tumors have functioning mitochondria?

    While I have not yet found a satisfactory description of his research methods, I am aware that at the Nobel Prize winning biologist Otto Heinrich Warburg believed at least from 1924 to 1966 that cancer cells generate their ATP primarily from anaerobic metabolism. He was awarded the Nobel Prize...
  13. Pythagorean

    Explaining Mitochondria Pattern Interest

    can any of you explain this interest pattern? http://www.google.com/insights/search/#q=mitochondria&geo=US&cmpt=q
  14. R

    Mitochondria - How it functions

    I was having a conversation with one of my family members about this. My biology education is limited as i did not focus on it in high school or in university. I understand that Mitochondira are considered the "energy factories" of a cell and that the term energy factory is not an accurate...
  15. Ahmed Abdullah

    What happen to our mitochondria when we take antibiotic like tetracyclines?

    Some antibiotic kills bacteria by inhibiting their protein synthesis. The idea is that, prokaryotic and eukaryotic protein synthesis machinery is not the same, so we can selectively use antibiotic that inhibit bacterial protein synthesis but not ours. Mitochondrion also known as the powerhouse...
  16. D

    Unraveling the Secrets of Mitochondria and Protein Synthesis

    homework help... Homework Statement why mitochondria is called the power house of the cell? which is the site for protein syntesis in a cell?? Homework Equations The Attempt at a Solution I found out that mitochondria is the site for protein synthesis but I think its kinda...
  17. P

    Mitochondria: Nucleus or No Nucleus?

    Do mitochondria have like tiny nucleus? and if not how do they control their DNA replication and translation... thnx
  18. S

    What causes a mutation in an enzyme that changes Tyrosine to Alanine?

    Ok, so we all know that Mitochdiria contains its own DNA, mDNA, which codes for 13 of the approx. 80 needed proteins. We all know, that mutations in the mDNA almost always cause diseases in the central-nervous-system, heart and muscles. Now, I've been asked the following question: One of...
  19. A

    Mitochondria evolution from a common ancestor

    So this morning, I wokeup and thought "mitochondria!" Weird huh? Why? Well, I thought of it as just another "proof" of evolution from a common ancestor. Not that anyone with an education should doubt it anyway, but just that we and bacteria have the same intracellular organelles should be...