A report on Mitochondrion

Two mitochondria from mammalian lung tissue displaying their matrix and membranes as shown by electron microscopy
Simplified structure of a mitochondrion.
Cross-sectional image of cristae in a rat liver mitochondrion to demonstrate the likely 3D structure and relationship to the inner membrane
Electron transport chain in the mitochondrial intermembrane space
Transmission electron micrograph of a chondrocyte, stained for calcium, showing its nucleus (N) and mitochondria (M).
Typical mitochondrial network (green) in two human cells (HeLa cells)
Model of the yeast multimeric tethering complex, ERMES
Evolution of MROs
The circular 16,569 bp human mitochondrial genome encoding 37 genes, i.e., 28 on the H-strand and 9 on the L-strand.

Double-membrane-bound organelle found in most eukaryotic organisms.

- Mitochondrion
Two mitochondria from mammalian lung tissue displaying their matrix and membranes as shown by electron microscopy

162 related topics with Alpha

Overall

A label diagram explaining the different parts of a prokaryotic genome

Genome

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All genetic information of an organism.

All genetic information of an organism.

A label diagram explaining the different parts of a prokaryotic genome
An image of the 46 chromosomes making up the diploid genome of a human male. (The mitochondrial chromosome is not shown.)
Part of DNA sequence - prototypification of complete genome of virus
Composition of the human genome
Log-log plot of the total number of annotated proteins in genomes submitted to GenBank as a function of genome size.

Eukaryotic genomes are even more difficult to define because almost all eukaryotic species contain nuclear chromosomes plus extra DNA molecules in the mitochondria.

Ribbon diagram of a monomer of human MAO-A, with FAD and clorgiline bound, oriented as if attached to the outer membrane of a mitochondrion. From.

Monoamine oxidase

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Monoamine oxidases (MAO) are a family of enzymes that catalyze the oxidation of monoamines, employing oxygen to clip off their amine group.

Monoamine oxidases (MAO) are a family of enzymes that catalyze the oxidation of monoamines, employing oxygen to clip off their amine group.

Ribbon diagram of a monomer of human MAO-A, with FAD and clorgiline bound, oriented as if attached to the outer membrane of a mitochondrion. From.
Norepinephrine degradation. Monoamine oxidase is shown left in the blue box.
Ribbon diagram of human MAO-B. From.

They are found bound to the outer membrane of mitochondria in most cell types of the body.

General schema showing the relationships of the genome, transcriptome, proteome, and metabolome (lipidome).

Proteome

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Entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time.

Entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time.

General schema showing the relationships of the genome, transcriptome, proteome, and metabolome (lipidome).
The proteome can be used to determine the presence of different types of cancers.
This image shows a two-dimensional gel with color-coded proteins. This is a way to visualize proteins based on their mass and isoelectric point.
An Orbitrap mass spectrometer commonly used in proteomics

For instance, the mitochondrial proteome may consist of more than 3000 distinct proteins.

The enzyme glucosidase converts the sugar maltose into two glucose sugars. Active site residues in red, maltose substrate in black, and NAD cofactor in yellow.

Enzyme

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Enzymes are proteins that act as biological catalysts (biocatalysts).

Enzymes are proteins that act as biological catalysts (biocatalysts).

The enzyme glucosidase converts the sugar maltose into two glucose sugars. Active site residues in red, maltose substrate in black, and NAD cofactor in yellow.
Eduard Buchner
Enzyme activity initially increases with temperature (Q10 coefficient) until the enzyme's structure unfolds (denaturation), leading to an optimal rate of reaction at an intermediate temperature.
Organisation of enzyme structure and lysozyme example. Binding sites in blue, catalytic site in red and peptidoglycan substrate in black.
Enzyme changes shape by induced fit upon substrate binding to form enzyme-substrate complex. Hexokinase has a large induced fit motion that closes over the substrates adenosine triphosphate and xylose. Binding sites in blue, substrates in black and Mg2+ cofactor in yellow.
Chemical structure for thiamine pyrophosphate and protein structure of transketolase. Thiamine pyrophosphate cofactor in yellow and xylulose 5-phosphate substrate in black.
The energies of the stages of a chemical reaction. Uncatalysed (dashed line), substrates need a lot of activation energy to reach a transition state, which then decays into lower-energy products. When enzyme catalysed (solid line), the enzyme binds the substrates (ES), then stabilizes the transition state (ES‡) to reduce the activation energy required to produce products (EP) which are finally released.
The metabolic pathway of glycolysis releases energy by converting glucose to pyruvate via a series of intermediate metabolites. Each chemical modification (red box) is performed by a different enzyme.
In phenylalanine hydroxylase over 300 different mutations throughout the structure cause phenylketonuria. Phenylalanine substrate and tetrahydrobiopterin coenzyme in black, and Fe2+ cofactor in yellow.
Hereditary defects in enzymes are generally inherited in an autosomal fashion because there are more non-X chromosomes than X-chromosomes, and a recessive fashion because the enzymes from the unaffected genes are generally sufficient to prevent symptoms in carriers.

For example, fatty acids are synthesized by one set of enzymes in the cytosol, endoplasmic reticulum and Golgi and used by a different set of enzymes as a source of energy in the mitochondrion, through β-oxidation.

Mitochondrial network (green) in two human cells (HeLa cells)

Mitochondrial fusion

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Mitochondrial network (green) in two human cells (HeLa cells)
Mitochondria, mammalian lung - TEM (2)

Mitochondria are dynamic organelles with the ability to fuse and divide (fission), forming constantly changing tubular networks in most eukaryotic cells.

An etoposide-treated DU145 prostate cancer cell exploding into a cascade of apoptotic bodies. The sub images were extracted from a 61-hour time-lapse microscopy video, created using quantitative phase-contrast microscopy. The optical thickness is color-coded. With increasing thickness, color changes from gray to yellow, red, purple and finally black. the video at The Cell: An Image Library

Apoptosis

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Form of programmed cell death that occurs in multicellular organisms.

Form of programmed cell death that occurs in multicellular organisms.

An etoposide-treated DU145 prostate cancer cell exploding into a cascade of apoptotic bodies. The sub images were extracted from a 61-hour time-lapse microscopy video, created using quantitative phase-contrast microscopy. The optical thickness is color-coded. With increasing thickness, color changes from gray to yellow, red, purple and finally black. the video at The Cell: An Image Library
Apoptosis begins when the nucleus of the cell begins to shrink. After the shrinking, the plasma membrane blebs and folds around different organelles. The blebs continue to form and the organelles fragment and move away from each other.
John Sulston won the Nobel Prize in Medicine in 2002, for his pioneering research on apoptosis.
Overview of signal transduction pathways.
Different steps in apoptotic cell disassembly.
Long-term live cell imaging (12h) of multinucleated mouse pre-Adipocyte trying to undergo mitosis. Due to the excess of genetic material the cell fails to replicate and dies by apoptosis.
A section of mouse liver showing several apoptotic cells, indicated by arrows
A section of mouse liver stained to show cells undergoing apoptosis (orange)
Neonatal cardiomyocytes ultrastructure after anoxia-reoxygenation.

The two best-understood activation mechanisms are the intrinsic pathway (also called the mitochondrial pathway) and the extrinsic pathway.

Mitosome

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Organelle found in some unicellular eukaryotic organisms, like in members of the supergroup Excavata.

Organelle found in some unicellular eukaryotic organisms, like in members of the supergroup Excavata.

The mitosome has been detected only in anaerobic or microaerophilic organisms that do not have mitochondria.

Illustration of the malate-aspartate shuttle pathway

Malate-aspartate shuttle

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Illustration of the malate-aspartate shuttle pathway

The malate-aspartate shuttle (sometimes simply the malate shuttle) is a biochemical system for translocating electrons produced during glycolysis across the semipermeable inner membrane of the mitochondrion for oxidative phosphorylation in eukaryotes.

Solution NMR structure of protein NMA1147 from Neisseria meningitidis. Northeast structural genomics consortium target mr19

Succinate dehydrogenase

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Enzyme complex, found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes.

Enzyme complex, found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes.

Solution NMR structure of protein NMA1147 from Neisseria meningitidis. Northeast structural genomics consortium target mr19
Image 5: Subunits of succinate dehydrogenase
Image 6: E2 Succinate oxidation mechanism.
Image 7: E1cb Succinate oxidation mechanism.
Image 8: Ubiquinone reduction mechanism.
Image 9: Electron carriers of the SQR complex. FADH2, iron-sulfur centers, heme b, and ubiquinone.

Mitochondrial and many bacterial SQRs are composed of four structurally different subunits: two hydrophilic and two hydrophobic.

Hepatocyte and sinusoid (venule) in a section of rat liver

Hepatocyte

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Protein synthesis

Protein synthesis

Hepatocyte and sinusoid (venule) in a section of rat liver
Schemic diagram of Biliary system

Hepatocytes display an eosinophilic cytoplasm, reflecting numerous mitochondria, and basophilic stippling due to large amounts of smooth endoplasmic reticulum and free ribosomes.