Oops, looks like the page is lost.Mit dem Anabolismus anabol katabol wiki er durch die Energiekopplung verbunden: Anabolismus und Katabolismus sind Teile des Metabolismus. Katabole und anabole Reaktionen laufen in der Zelle nicht gleichzeitig ab. Im Rahmen einer Atrophie z. HerzinfarktSchlaganfall findet ein gesteigerter Katabolismus statt, bei Doping oder physiologischem Wachstum hingegen ist er gesenkt. Glukose-StoffwechselBlutzuckerGlucagonInsulin. Stoffwechsel — Metabolism is iwki set of life-sustaining chemical transformations within the anabol katabol wiki of living organisms.
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Mit dem Anabolismus ist er durch die Energiekopplung verbunden: Anabolismus und Katabolismus sind Teile des Metabolismus. Katabole und anabole Reaktionen laufen in der Zelle nicht gleichzeitig ab. Im Rahmen einer Atrophie z. Herzinfarkt , Schlaganfall findet ein gesteigerter Katabolismus statt, bei Doping oder physiologischem Wachstum hingegen ist er gesenkt. Glukose-Stoffwechsel , Blutzucker , Glucagon , Insulin. Stoffwechsel — Metabolism is the set of life-sustaining chemical transformations within the cells of living organisms.
These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, usually, breaking down releases energy and building up consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in one chemical is transformed through a series of steps into another chemical. Enzymes act as catalysts that allow the reactions to proceed more rapidly, enzymes also allow the regulation of metabolic pathways in response to changes in the cells environment or to signals from other cells.
The metabolic system of a particular organism determines which substances it will find nutritious, for example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the rate, influences how much food an organism will require. A striking feature of metabolism is the similarity of the metabolic pathways. These striking similarities in metabolic pathways are likely due to their appearance in evolutionary history.
Most of the structures that make up animals, plants and microbes are made from three classes of molecule, amino acids, carbohydrates and lipids.
These biochemicals can be joined together to make such as DNA and proteins. Proteins are made of amino acids arranged in a linear chain joined together by peptide bonds, many proteins are enzymes that catalyze the chemical reactions in metabolism.
Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Lipids are the most diverse group of biochemicals and their main structural uses are as part of biological membranes both internal and external, such as the cell membrane, or as a source of energy.
Lipids are usually defined as hydrophobic or amphipathic biological molecules but will dissolve in organic solvents such as benzene or chloroform, the fats are a large group of compounds that contain fatty acids and glycerol, a glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Several variations on this structure exist, including alternate backbones such as sphingosine in the sphingolipids.
Steroids such as cholesterol are another class of lipids. Carbohydrates are aldehydes or ketones, with hydroxyl groups attached. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy, the basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose.
Molecules are distinguished from ions by their lack of electrical charge, however, in quantum physics, organic chemistry, and biochemistry, the term molecule is often used less strictly, also being applied to polyatomic ions.
In the kinetic theory of gases, the molecule is often used for any gaseous particle regardless of its composition.
According to this definition, noble gas atoms are considered molecules as they are in fact monoatomic molecules. A molecule may be homonuclear, that is, it consists of atoms of one element, as with oxygen, or it may be heteronuclear. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are not considered single molecules.
Molecules as components of matter are common in organic substances and they also make up most of the oceans and atmosphere. Also, no typical molecule can be defined for ionic crystals and covalent crystals, the theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding, which means that solid metals are also not made of molecules.
In glasses, atoms may also be together by chemical bonds with no presence of any definable molecule. The science of molecules is called molecular chemistry or molecular physics, in practice, however, this distinction is vague. In molecular sciences, a molecule consists of a system composed of two or more atoms. Polyatomic ions may sometimes be thought of as electrically charged molecules. The term unstable molecule is used for very reactive species, i.
The definition of the molecule has evolved as knowledge of the structure of molecules has increased, earlier definitions were less precise, defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties. Molecules are held together by covalent bonding or ionic bonding.
Several types of non-metal elements exist only as molecules in the environment, for example, hydrogen only exists as hydrogen molecule. A molecule of a compound is made out of two or more elements, a covalent bond is a chemical bond that involves the sharing of electron pairs between atoms.
Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology, enzymes are known to catalyze more than 5, biochemical reaction types.
Most enzymes are proteins, although a few are catalytic RNA molecules, enzymes specificity comes from their unique three-dimensional structures.
Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy, some enzymes can make their conversion of substrate to product occur many millions of times faster.
An extreme example is orotidine 5-phosphate decarboxylase, which allows a reaction that would take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, enzymes differ from most other catalysts by being much more specific.
Enzyme activity can be affected by other molecules, inhibitors are molecules that decrease enzyme activity, many drugs and poisons are enzyme inhibitors. An enzymes activity decreases markedly outside its optimal temperature and pH, some enzymes are used commercially, for example, in the synthesis of antibiotics.
French chemist Anselme Payen was the first to discover an enzyme, diastase and he wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells.
Eduard Buchner submitted his first paper on the study of yeast extracts in , in a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture. He named the enzyme that brought about the fermentation of sucrose zymase, in , he received the Nobel Prize in Chemistry for his discovery of cell-free fermentation. Following Buchners example, enzymes are usually named according to the reaction they carry out, the biochemical identity of enzymes was still unknown in the early s.
Sumner showed that the enzyme urease was a protein and crystallized it. These three scientists were awarded the Nobel Prize in Chemistry, the discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography. This high-resolution structure of lysozyme marked the beginning of the field of structural biology, an enzymes name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase.
Glykogen — Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in humans, animals, and fungi. The polysaccharide structure represents the main form of glucose in the body. In humans, glycogen is made and stored primarily in the cells of the liver, glycogen functions as the secondary long-term energy storage, with the primary energy stores being fats held in adipose tissue. Muscle glycogen is converted into glucose by muscle cells, and liver glycogen converts to glucose for use throughout the body including the nervous system.
Glycogen is the analogue of starch, a polymer that functions as energy storage in plants. It has a similar to amylopectin, but is more extensively branched. Glycogen forms a reserve that can be quickly mobilized to meet a sudden need for glucose. Only the glycogen stored in the liver can be accessible to other organs. In the muscles, glycogen is found in a low concentration, the amount of glycogen stored in the body—especially within the muscles, liver, and red blood cells—mostly depends on physical training, basal metabolic rate, and eating habits.
Small amounts of glycogen are found in the kidneys, and even smaller amounts in certain cells in the brain. The uterus also stores glycogen during pregnancy to nourish the embryo, glycogen is a branched biopolymer consisting of linear chains of glucose residues with further chains branching off every 8 to 12 glucoses or so.
Due to the way glycogen is synthesised, every glycogen granule has at its core a glycogenin protein. Glycogen in muscle, liver, and fat cells is stored in a hydrated form, as a meal containing carbohydrates or protein is eaten and digested, blood glucose levels rise, and the pancreas secretes insulin. Blood glucose from the vein enters liver cells.
Insulin acts on the hepatocytes to stimulate the action of several enzymes, glucose molecules are added to the chains of glycogen as long as both insulin and glucose remain plentiful. In biology, phosphorylation and its counterpart, dephosphorylation, are critical for cellular processes. A large fraction of proteins are at least temporarily phosphorylated, as are many sugars, lipids, Phosphorylation is especially important for protein function as this modification activates many enzymes, thereby regulating their function.
Protein phosphorylation is one type of post-translational modification, the prominent role of protein phosphorylation in biochemistry is illustrated by the huge body of studies published on the subject. Phosphorylation of sugars is often the first stage of their catabolism and it allows cells to accumulate sugars because the phosphate group prevents the molecules from diffusing back across their transporter.
Phosphorylation of glucose is a key reaction in sugar metabolism because many sugars are first converted to glucose before they are metabolized further. Hepatic cell is freely permeable to glucose, and the rate of phosphorylation of glucose is the rate-limiting step in glucose metabolism by the liver. The role of glucose 6-phosphate in glycogen synthase, High blood glucose concentration causes an increase in levels of glucose 6 phosphate in liver, skeletal muscle. In liver, synthesis of glycogen is directly correlated by blood glucose concentration and in muscle and adipocytes.
High blood glucose releases insulin, stimulating the trans location of specific glucose transporters to the cell membrane, the hexokinase enzyme has a low Km, indicating a high affinity for glucose, so this initial phosphorylation can proceed even when glucose levels at nanoscopic scale within the blood. The phosphorylation of glucose can be enhanced by the binding of Fructosephosphate, fructose consumed in the diet is converted to F1P in the liver. This negates the action of F6P on glucokinase, which favors the forward reaction.
The capacity of cells to phosphorylate fructose exceeds capacity of metabolize fructosephosphate. Consuming excess fructose ultimately results in an imbalance in liver metabolism, Phosphorylation of glucose is imperative in processes within the body. For example, phosphorylating glucose is necessary for insulin-dependent mechanistic target of rapamycin pathway activity within the heart and this further suggests a link between intermediary metabolism and cardiac growth. Reversible phosphorylation of proteins is an important regulatory mechanism occurs in both prokaryotic and eukaryotic organisms.
Kinases phosphorylate proteins and phosphatases dephosphorylate proteins, many enzymes and receptors are switched on or off by phosphorylation and dephosphorylation. Nekrose — Necrosis is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by external to the cell or tissue, such as infection, toxins. In contrast, apoptosis is a naturally occurring programmed and targeted cause of cellular death, while apoptosis often provides beneficial effects to the organism, necrosis is almost always detrimental and can be fatal.
This initiates in the tissue a inflammatory response which attracts leukocytes. However, microbial damaging substances released by leukocytes would create collateral damage to surrounding tissues, too much collateral damage would inhibit the healing process.
Thus, untreated necrosis results in a build-up of decomposing dead tissue, for this reason, it is often necessary to remove necrotic tissue surgically, a procedure known as debridement. Coagulation occurs as a result of protein denaturation, causing albumin to transform into a firm and this pattern of necrosis is typically seen in hypoxic environments, such as infarction.
Coagulative necrosis occurs primarily in tissues such as the kidney, heart, severe ischemia most commonly causes necrosis of this form. Liquefactive necrosis, in contrast to necrosis, is characterized by the digestion of dead cells to form a viscous liquid mass. This is typical of bacterial, or sometimes fungal, infections because of their ability to stimulate an inflammatory response, the necrotic liquid mass is frequently creamy yellow due to the presence of dead leukocytes and is commonly known as pus.
Gangrenous necrosis can be considered a type of coagulative necrosis that resembles mummified tissue and it is characteristic of ischemia of lower limb and the gastrointestinal tracts. The necrotic tissue appears as white and friable, like clumped cheese, dead cells disintegrate but are not completely digested, leaving granular particles.