I Can’t Sleep - Mitochondrion | Gentle Bedtime Reading for Sleep

Episode Date: January 30, 2020

Ease into sleep with calm bedtime reading about the mitochondrion to help with insomnia and restless nights. This soothing episode explores the tiny but powerful organelle often called the “powerhouse of the cell.” Benjamin’s peaceful cadence makes complex biology relaxing, guiding you through how mitochondria create energy, their role in cellular health, and their fascinating evolutionary history. There’s no whispering or hypnosis—just gentle, fact-filled storytelling to calm the mind, reduce stress, and help you drift off. Want More? Request a Topic: https://www.icantsleeppodcast.com/request-a-topic Ad-Free Episodes: https://icantsleep.supportingcast.fm/ Shop Sleep-Friendly Products: https://www.icantsleeppodcast.com/sponsors Join the Discussion on Discord: https://discord.gg/myhGhVUhn7 This content is derived from the Wikipedia article on Mitochondrion, available under the Creative Commons Attribution-ShareAlike (CC BY-SA) license. Read the full article: Wikipedia – Mitochondrion. Happy sleeping! Learn more about your ad choices. Visit megaphone.fm/adchoices

You're listening to a Glassbox media podcast. What if I told you that most of the modern day self-help advice you've been hearing could actually make you worse? The key to a better life isn't about feel-good gimmicks that sound catchy. The Mentally Stronger Podcast gives you access to a licensed therapist who shares science-backed tools that will actually change your life. Hi, I'm Amy Morin, psychotherapist, mental strength trainer, and international best-selling author. In each episode, we cover research-back strategies, like how to stop relying on willpower and start creating habits for lasting change. And the five mental strength-building exercises you can do from your couch. I also speak to world-class experts like Dr. Nicole Kane, who shares how to permanently heal anxiety by addressing the root cause.

With over 200 episodes in our catalog, this podcast is for you if you're ready to crush self-doubt, conquer challenges, become stronger than ever with therapist-approved strategies that can change your life. Listen to Mentally Stronger with Therapist Amy Morin, wherever you get your podcasts. Welcome to the I Can't Sleep podcast, where I read random articles from across the web to bore you to sleep with my soothing voice. I'm your host Benjamin Boster, and today's episode is from a Wikipedia article titled Mitochondrian.

The mitochondrian, plural mitochondria, is a double membrane-bound organelle found in most eukaryotic organisms. Some cells and some multicellular organisms may, however,

lack them. For example, mature mammalian red blood cells. A number of unicellular organisms, such as microspridia, parabic salads and diplominids have also reduced or transformed their mitochondria into other structures. To date, only one eukaryote monocercominides is known to have completely lost its mitochondria.

The word mitochondria comes from the Greek mitos thread and chondrian, granule, or grain-like. mitochondria generate most of the cell's supply of adenosine trifosate, ATP, used as a source of chemical energy. A mitochondrian is thus termed the powerhouse of the cell. Mitocondria are commonly between 0.75 and 3 micrometers squared in area, but vary considerably in size and structure. Unless specifically stained, they are, 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. Mitocondriobiogenesis is in turn temporarily coordinated with these cellular processes. Mitocondria have been implicated in several human diseases, diseases, including mitochondrial disorders, cardiac dysfunction, heart failure, and autism. The number of mitochondria in a cell can vary widely by organism, tissue, and cell type. For instance, red blood cells have no mitochondria, whereas liver cells can have more than 2,000. 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 Christi and matrix.

Although most of a cell's DNA is contained in the cell nucleus, the mitochondrian has its own independent genome that shows substantial similarity to bacterial genomes. mitochondrial proteins, proteins transcribed from mitochondrial DNA, vary depending on the tissue and the species. In humans, 615 distinct types of protein have been identified from cardiac mitochondria, whereas in rats, 940 proteins have been reported. The mitochondrial proteum is thought to be dynamically regulated. History of Discovery and Research The first observations of intracellular structures that probably represented mitochondria were published in the 1840s.

Richard Altman in 1890 established them as cell organelles and called them bioblasts. The term mitochondria was coined by Carl Benda in 1898. Leonor Michaelis discovered that Jenna Screen can be used, as a supervital stain for mitochondria in 1900. In 1904, Friedrich Meves made the first recorded observation of mitochondria and plants and cells of the white water lily. And in 1908, along with Claudius Regaud, suggested that they contained proteins and lipids. Benjamin F. Kingsbury in 1912 first related them to the cell respiration, but almost exclusively

based on morphological observations. In 1913, particles from extracts of guinea pig liver were linked to respiration by Otto Heinrich Varberg, which he called Grana. Varberg and Heinrich Otto Veland, who had also postulated a similar particle mechanism, disagreed on the chemical nature of the respiration. It was not until 1925 when David Kylan discovered cytocrums that the respiratory a chain was described. In 1939, experiments using minced muscle cells demonstrated that cellular respiration using one oxygen atom can form two adenosine-triphosphate ATP molecules. And in 1941,

the concept of the phosphate bonds of ATP, being a form of energy and cellular metabolism, was developed by Fritz Albert Libman. In the following years, the mechanism behind cellular respiration was further elaborated, although its link to the mitochondria was not known. The introduction of tissue fractionation by Albert Claude allowed mitochondria to be isolated from other cell fractions and biochemical analysis to be conducted on them alone. In 1946, he concluded that cytochrome oxidase and other enzymes responsible for respiratory chain were isolated to the mitochondria. Eugene Kennedy and Albert Leninger discovered in 1948

that mitochondria are the site of oxidative phosphorylation in eukaryotes. Over time, the fractionation method was further developed, improving the quality of the mitochondria isolated, and other elements of cell respiration were determined to occur in the mitochondria. The first high-resolution electron micrographs appeared in 1952, replacing the Janus Green Stains as the preferred way, of visualizing the mitochondria. This led to a more detailed analysis of the structure of the mitochondria, including confirmation that they were surrounded by a membrane. It also showed a second

membrane inside the mitochondria that folded up in ridges, dividing up the inner chamber, and that the size and shape of the mitochondria varied from cell to cell. The popular term powerhouse of the cell was coined by Philip Seekovitz in 19. In 1967, it was discovered that mitochondria contained ribosomes. In 1968, methods were developed for mapping and mitochondrial genes, with the genetic and physical map of yeast mitochondrial DNA being completed in 1976. Origin and Evolution There are two hypotheses about the origin of mitochondria, endosymbiotic and autogenous.

The endosymbiotic hypothesis suggests that the mitochondria were originally prokaryotic cells, capable of implementing oxidative mechanisms that were not possible for eukaryotic cells. They became endosymbiance living inside the eukaryote. In the autogenes hypothesis, mitochondria were born by splitting off a portion of DNA from the nucleus of the eukaryotic cell at the time of divergence with the prokaryotic. This DNA portion would have been enclosed by membranes, which could not be crossed by proteins. Since mitochondria have many features in common with bacteria, the endosymbiotic hypothesis is more widely accepted. A mitochondrian contains DNA, which is organized as several copies of a single, usually circular chromosome.

This mitochondrial chromosome contains genes for redox proteins, such as those of the respiratory chain. The core hypothesis proposes that this co-location is required for redox regulation. The mitochondrial genome codes for some RNAs of ribosomes, and the 22-T RNAs necessary for the translation of MRNAs into protein. The circular structure is also found in prokaryotes. The proto-miticondrian was probably closely related to the Rickettsa. However, the exact relationship of the ancestor of mitochondria to the alpha-proteobacteria

and whether the mitochondria was formed at the same time or after the nucleus remains controversial. For example, it has been suggested that the S-A-R-11 clade of bacteria, a relatively recent common ancestor with the mitochondria. While philogynomic analysis indicate that mitochondria evolved from a proteobacteria lineage is closely related to or a member of alpha proteobacteria. The ribosomes coded for by the mitochondrial DNA are similar to those from bacteria in size and structure. They closely resemble the bacterial 70s ribosome. and not the 80s cytoplasmic ribosomes,

which are coded for by nuclear DNA. The endosymbiotic relationship of mitochondria with their host cells was popularized by Lynn Margulis. The endosymbiotic hypothesis suggests that mitochondria descended from bacteria that somehow survived endocytosis by another cell, and became incorporated into the cytoplasm. The ability of these bacteria to conduct respiration in host cells that had relied on glycosis and fermentation would have provided a considerable evolutionary advantage.

This symbiotic relationship probably developed 1.7 to 2 billion years ago. A few groups of unicellular eukaryotes have only vestigial mitochondria or derived structures. The Microsperidians, Metaminads, and Archimobi. These groups appear as the most primitive eukaryotes on polygenetic trees constructed using RNA information, which once suggested that they appeared before the origin of mitochondria. However, this is now known to be an artifact of long branch attraction. They are derived groups and retained genes or organelles derived from mitochondria,

e.g. mitasomes and hydrogenosomes. Monocircominoids appear to have lost their mitochondria completely, and at least some of the mitochondrial functions seem to be carried out by cytoplasmic proteins now. A mitochondrion contains outer and inner membranes composed of phospholipid bilayers and proteins. The two membranes have different properties. Because of this double membrane organization, there are five distinct parts to a mitochondrian. They are, one, the outer mitochondrial membrane, two, the intermembrane space, the space between the outer and inner membranes. Three, the inner mitochondrial membrane.

Four, the creste space, formed by infoldings of the inner membrane. and five, the matrix, spaced between the inner membrane. Mitochondria stripped of their outer membrane are called mitoplasts. Outer membrane. The outer mitochondrial membrane, which encloses the entire organelle, is 60 to 75 Engstrom's thick. It has a protein to phospholipid ratio similar to that of the cell membrane, about one to one by weight.

It contains large numbers of integral membrane, proteins called porins. A major trafficking protein is the pore forming voltage-dependent anion channel, VDAC. The VDAC is the primary transporter of nucleotides, ions, and metabolites between the cytosol and the intermembrane space. It is formed as a beta barrel that spans the outer membrane, similar to that in the gram-negative bacterial membrane. Larger proteins can enter the mitochondrian if a signaling sequence at their end terminus binds to a large multi-subunit protein called translocase in the outer membrane, which then actively moves them across the membrane. Mitochondrial pro proteins are imported through specialized translocation complexes. The outer membrane also contains enzymes involved in such diverse activities as the elliocondrile.

elongation of fatty acids, oxidation of epinephrine, and the degradation of tryptophan. These enzymes include monamine oxidase, rotan-intense N-A-D-H, cytochrome Cidreductase, chinerian hydroxylase, and fatty acid co-a-ligase. Disruption of the outer membrane permits proteins in the intermembrane space to leak into the cytosol, leading to certain cell death. The mitochondrial outer membrane can associate with the endoplasmic reticulum, ER membrane, in a structure called MAM, mitochondria-associated ER membrane. This is important in the ER mitochondria calcium signaling

and is involved in the transfer of lipids between the ER and mitochondria. Outside the outer membrane, there are smaller particles named subunits of Parson. Intermembrane space The mitochondrial intermembrane space is the space between the outer membrane and the inner membrane. It is also known as paramytochondrial space. Because the outer membrane is fairly permeable to small molecules, the concentrations of small molecules such as ions and sugars, and the inner membrane space is the same as in the cytosol.

However, large proteins must have a specific signaling sequence to be transported across the outer membrane. So the protein composition of this space is different from the protein composition of the cytosol. One protein that is localized to the intermembrane space in this way is cytochrome C. Inner membrane. The inner mitochondrial membrane contains proteins with five types of functions. One, those that perform the redox reactions of oxidative phosphorylation. Two, ATP synthase, which generates ATP in the matrix. three specific transport proteins that regulate metabolite passage into and out of the mitochondrial matrix.

Four, protein import machinery. Five, mitochondrial fusion and fission protein. It contains more than 151 different polypeptides and has a very high protein to phospholipid ratio, more than three to one by weight, which is about one protein for 15 phospholipids. The inner membrane is home to around one-fifth of the total protein in a mitochondriaean. In addition, the inner membrane is rich in an unusual phospholipid, cardiolipin. This phospholipid was originally discovered in cow hearts in 1942, and is usually characteristic of mitochondrial and bacterial plasma membranes.

Cardiolipin contains four fatty acids rather than two, and may help to make the inner membrane impermeable. Unlike the outer membrane, the inner membrane does not contain porins and is highly impermeable to all molecules. Almost all ions and molecules require special membrane transporters to enter or exit the matrix. Proteins are ferried into the matrix via the translocase of the inner membrane, T-I-Mexmplex,

or via Oaksa-1. In addition, there is a membrane potential across the inner membrane, formed by the action of the enzymes of the electron transport chain. Crestae The inner mitochondrial membrane is compartmentalized into numerous Crestes, which expand the surface area of the inner mitochondrial membrane, enhancing its ability to produce ATP. For typical liver mitochondria, the area of the inner membrane is about five times as large as the outer membrane. This ratio is variable, and mitochondria from cells that have a greater demand for ATP, such as muscle cells, contain even more crustae. Mitochondria within the same cell can have substantially different crusta density.

The ones that are required to produce more energy have much more chrystam membrane surface. These folds are studded with small round bodies known as F1 particles or oxysomes. These are not simple random folds, but rather invaginations of the inner membrane, which can affect overall chemoismotic function. One recent mathematical modeling study has suggested that the optical properties of the crested and filamentous mitochondria may affect the generation and propagation of light within the tissue. Matrix The matrix is the space enclosed by the inner membrane.

It contains about two-thirds of the total protein in a mitochondriaen. The matrix is important in the production of ATP with the aid of the ATP synthase contained in the inner membrane. The matrix contains a highly concentrated mixture of hundreds of enzymes, special mitochondrial ribosomes, T-RNA, and several copies of the mitochondrial DNA genome. Of the enzymes, the major functions include oxygen, of pyruvate and fatty acids and the citric acid cycle.

The DNA molecules are packaged in nucleoids by proteins, one of which is Tfam. Mitochondria have their own genetic material and the machinery to manufacture their own RNAs and proteins. A published human mitochondrial DNA sequence revealed 16,569 base pairs, encoding 37 genes. 22T RNA, 2RRNA, and 13 peptide genes. The 13 mitochondrial peptides in humans are integrated into the inner mitochondrial membrane, along with proteins encoded by genes that reside in the host cells nucleus.