Examples of mitochondria in the following topics:
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- One of the major features distinguishing prokaryotes from eukaryotes is the presence of mitochondria.
- Mitochondria are double-membraned organelles that contain their own ribosomes and DNA.
- These features all support the hypothesis that mitochondria were once free-living prokaryotes.
- In mitochondria, this process uses oxygen and produces carbon dioxide as a waste product.
- In addition to the aerobic generation of ATP, mitochondria have several other metabolic functions.
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- One of the major features distinguishing prokaryotes from eukaryotes is the presence of mitochondria.
- Mitochondria arise from the division of existing mitochondria.
- However, mitochondria cannot survive outside the cell.
- These features all support that mitochondria were once free-living prokaryotes.
- Despite the transfer of genes between mitochondria and the nucleus, mitochondria retain much of their own independent genetic material.
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- Energy is often released in the form of protium or H+, moving down an electrochemical gradient, such as from the lumen into the stroma of chloroplasts or from the inter-membrane space into the matrix in mitochondria.
- Located within the mitochondria, ATP synthase consists of 2 regions: the FO portion is within the membrane and the F1 portion of the ATP synthase is above the membrane, inside the matrix of the mitochondria .
- They were originally called elementary particles and were thought to contain the entire respiratory apparatus of the mitochondrion, but, through a long series of experiments, Ephraim Racker and his colleagues (who first isolated the F1 particle in 1961) were able to show that this particle is correlated with ATPase activity in uncoupled mitochondria and with the ATPase activity in submitochondrial particles created by exposing mitochondria to ultrasound.
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- Cardiac cells contain numerous mitochondria, which enable continuous aerobic respiration and production of ATP for cardiac function.
- Cardiomyocytes contain large numbers of mitochondria, the power house of the cell, enabling continuous aerobic respiration and production of ATP, which is required for mechanical muscle contraction.
- Cardiac muscle tissue has among the highest energy requirements in the human body (along with the brain) and has a high level of mitochondria and a constant, rich, blood supply to support its metabolic activity.
- Cardiac muscle cells contain larger amounts of mitochondria relative to other cells in the body, which enable higher ATP production.
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- This mechanism is an aspect of the Endosymbiont Theory, which is accepted by a majority of biologists as the mechanism whereby eukaryotic cells obtained their mitochondria and chloroplasts.
- This mechanism has also been used to explain the double membranes found in mitochondria and chloroplasts.
- Another hypothesis, the nucleus-first hypothesis, proposes the nucleus evolved in prokaryotes first, followed by a later fusion of the new eukaryote with bacteria that became mitochondria.
- The mitochondria-first hypothesis, however, proposes mitochondria were first established in a prokaryotic host, which subsequently acquired a nucleus (by fusion or other mechanisms) to become the first eukaryotic cell.
- The theory that mitochondria and chloroplasts are endosymbiotic in origin is now widely accepted.
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- Rickettsia are one of closest living relatives to bacteria that were the origin of the mitochondria organelle that exists inside most eukaryotic cells.
- In this regard, certain segments of Rickettsia genomes resemble that of mitochondria, and ATP production is the same as that in mitochondria.
- The genomes of both Rickettsia and mitochondria are frequently said to be "small, highly derived products of several types of reductive evolution. "
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- There is compelling evidence that mitochondria and chloroplasts were once primitive bacterial cells.
- Over millions of years of evolution, mitochondria and chloroplasts have become more specialized and today they cannot live outside the cell.
- Mitochondria and chloroplasts have striking similarities to bacteria cells.
- A double membrane surrounding both mitochondria and chloroplasts is further evidence that each was ingested by a primitive host.
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- Most eukaryotic cells also contain other membrane-bound organelles such as mitochondria, chloroplasts, and the Golgi apparatus.
- The few groups that lack mitochondria branched separately, and so the absence was believed to be primitive.
- The last common ancestor of all eukaryotes is believed to have been a phagotrophic protist with a nucleus, at least one centriole and cilium, facultatively aerobic mitochondria, sex (meiosis), a dormant cyst with a cell wall of chitin, cellulose, and peroxisomes.
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- Another source of variance occurs during the shuttle of electrons across the membranes of the mitochondria.
- The NADH generated from glycolysis cannot easily enter mitochondria.
- Thus, electrons are picked up on the inside of mitochondria by either NAD+ or FAD+.
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- Ivan Wallin extended the idea of an endosymbiotic origin to mitochondria in the 1920s.
- More detailed electron microscopic comparisons between cyanobacteria and chloroplasts combined with the discovery that plastids (organelles associated with photosynthesis) and mitochondria contain their own DNA led to a resurrection of the idea in the 1960s.
- A eukaryote with mitochondria engulfed a cyanobacterium in an event of serial primary endosymbiosis, creating a lineage of cells with both organelles.