reactions

Vesicle

...cles can be used as reaction chambers for chemical reactions that could damage the cell if they would occur in the cytosol. For example, peroxisomes are detoxifiers of hydrogen peroxide (H 2 O 2 ), a toxic byproduct of cell metabolism. Large storage vesicles are known as vacuoles . Mechanisms Assembly...

Urea cycle

The Urea Cycle is a cycle of biochemical reactions occurring in many animal organisms that produces urea from ammonia . This cycle, also known as ornithine cycle, was the first metabolic cycle discovered (Krebs and Hensenleit, 1932) Urea is much less toxic than ammonia, therefore organisms which ...

Thermoregulation

...denatured at temperature extremes and metabolic reactions occur best at certain temperatures; both endotherms , which control the build-up of heat from aerobic respiration (homeotherms ) and ectotherms (poikilotherms ) can thermoregulate but only the endotherms (birds and mammals) can maintain a stable b...

T cell

...ls, tumor cells and is also involved in rejection reactions . CD4 and CD8 refer to the characteristic antigens on the surface of the different sub-types of T-lymphocytes. These CD molecules are convenient diagnostic markers for identifying and quantitating these cells by flow cytometry using specific ...

Stroma

...hylakoid membranes wherein the light-independent reactions ( Calvin Cycle and Carbon fixation ) of photosynthesis take place....

Signal transduction

...duction often involve a sequence of biochemical reactions inside the cell, which are carried out by enzyme...n of the signal that leads to defined biochemical reactions within the target cell. The reactions of the target cells can, in turn, cause a signal to the hormon...

Second messenger

...hesized/released and broken down again in specific reactions by enzymes. Some (like Ca 2+ ) can be stored in special organelles and quickly released when needed. Their production/release and destruction can be localized , enabling the cell to limit space and time of signal activity....

RNA

...r catalytic versatility and allows it to perform reactions that DNA is incapable of performing; but at the sa...c information like DNA and to catalyze biochemical reactions like an enzyme. In effect, RNA was, before the emergence of the first cell , the dominant, and prob...

Redox

The most fundamental reactions in chemistry are the redox processes .The term re... meaning (Oxygen/Hydrogen) 3 Examples of redox reactions 3.1 Other examples 4 Redox reactions in biology 5 See also 6 External link ...

Protein

...eins can often figure in allergies and allergic reactions to certain foods . This is because the structure of each form of protein is slightly different, and some may trigger a response from the immune system while others are perfectly safe. Many people are allergic to casein , the protein in milk; glut...

Primary nutritional groups

...it is chemotrophic when it conserves energy from reactions of chemical compounds. The basis for energy met...st chemotrophic organisms are oxidation-reduction reactions in which electrons move from an electron donor to an electron acceptor . Energy is released duri...

Photosynthesis

... proteins ). These are called light-independent reactions , or dark reactions, since they can occur in the absence of light. However, when oxygen is abundant in the chloroplast in comparison to carbon dioxide due to some reason, such as competition in a dense overgrowth or closure of stomata, photorespira...

Phospholipid

...synthesized via two separate pathways; a series of reactions similar to phosphatidyl ethanolamine synthesis, and the methylation of phosphatidyl ethanolamine, which is catalyzed by phosphatidyl ethanolamine methyltransferase, an enzyme found in the liver. Sphingomyelin The backbone of sphingomyelin is sp...

Pentose phosphate pathway

... 2 H + + CO 2 The first step in this series of reactions is the dehydrogenation of glucose 6-phosphate ...ate into ribose 5-phosphate . The entire set of reactions can be summarized as follows: Glucose 6-phosphate + NADP+ → 6-phosphoglucono-δ-lactone ...

Polymerase chain reaction

...ould be the same. Following PCR, these two sets of reactions would be run out on an agarose gel, and the band pattern will tell you if the individual is homozygous T, homozygous C, or heterzygous T/C. This methodology has several applications, such as amplifying certain haplotypes (when certain alleles at 2 o...

Redox

The most fundamental reactions in chemistry are the redox processes .The term re... meaning (Oxygen/Hydrogen) 3 Examples of redox reactions 3.1 Other examples 4 Redox reactions in biology 5 See also 6 External link ...

Origin of life

... of tracing today's biochemistry back to ancestral reactions that provide alternative pathways to the synthesis...als (e. g. pyrite). The energy released from redox reactions of these metal sulfides is not only available for the synthesis of organic molecules, but also for t...

Nicotinamide adenine dinucleotide

...hotosynthesis. It is used in many other anabolic reactions in various organisms as well. MH 2 + NAD + → NADH + H + + M: + energy, where M is a metabolite. Two hydrogen ions (a hydride ion and an H + ion) are transferred from the metabolite. Two electrons are transferred to the positively char...

Nicotinamide adenine dinucleotide

...hotosynthesis. It is used in many other anabolic reactions in various organisms as well. MH 2 + NAD + → NADH + H + + M: + energy, where M is a metabolite. Two hydrogen ions (a hydride ion and an H + ion) are transferred from the metabolite. Two electrons are transferred to the positively char...

Nicotinamide adenine dinucleotide

...hotosynthesis. It is used in many other anabolic reactions in various organisms as well. MH 2 + NAD + → NADH + H + + M: + energy, where M is a metabolite. Two hydrogen ions (a hydride ion and an H + ion) are transferred from the metabolite. Two electrons are transferred to the positively char...

Michaelis-Menten kinetics

...en kinetics describe the rate of enzyme mediated reactions for many enzymes. It is named for Leonor Michael...e factors that effect the rate of enzyme mediated reactions (ie. pH, temperature, etc) are at optimal values. Diagram of reaction speed and Michaelis-Ment...

Louis Pasteur

...cal synthesis had no such effect, even though its reactions were identical and its elemental composition was the same. Pasteur noticed, upon examination of the tiny crystals of tartaric acid, that the crystals came in two asymmetric forms that were mirror images of one another. Tediously sorting the cryst...

Life

...us functions. They do so by coupling the exergonic reactions of nutrient oxidation to the endergonic processes required to maintain the living state, such as the performance of mechanical work, the active transport of molecules against concentration gradients, and the biosynthesis of complex molecules." This d...

Citric acid cycle

...le, or the Krebs cycle ) is a series of chemical reactions of central importance in all living cells that ...nds such as certain amino acids , and some of its reactions are therefore important even in cells performing fermentation . Contents showTocToggle("show"...

Insulin

...y the result of preparation purity and of allergic reactions to assorted non-insulin substances remaining in th...e insulin, adjust the pH of the solution to reduce reactions at the injection site, and so on. Some recent insulins are not even precisely insulin, but so called...

Hydrolysis

... peptide link of amino acids In other hydrolysis reactions such as hydrolysing the peptide links of amino acids only one of the products, the carboxylic acid product, has a hydroxide group derived from the water. The amine product gains the remaining hydrogen ion. Hydrolysis can be considered as the opp...

Homeostasis

...urea . Since these properties affect the chemical reactions that keep bodies alive, there are built-in physiological mechanisms to maintain them at desirable levels. However, it should be noted that homeostasis is not the reason for these ongoing unconscious adjustments. Homeostasis should be thought of as...

Photosynthesis

... proteins ). These are called light-independent reactions , or dark reactions, since they can occur in the absence of light. However, when oxygen is abundant in the chloroplast in comparison to carbon dioxide due to some reason, such as competition in a dense overgrowth or closure of stomata, photorespira...

Glycolysis

...he cell (as opposed to the mitochondria , where reactions more closely connected to aerobic metabolism occ...ormation of fructose 1,6 bisphosphate, many of the reactions are energetically unfavorable. The only reactions that are favorable are the 2 substrate-level phosp...

Genetic recombination

...over Enzymes known as recombinases catalyze the reactions that allow for crossover to occur. A recombinase creates a nick in one strand of a DNA double helix, allowing the nicked strand to pull apart from its complementary strand and anneal to one strand of the double helix on the opposite chromatid. ...

Eugenics

...l highly discriminatory). Along with these other reactions to Nazi ideas, eugenics was almost universally reviled in many of the nations in which it had once been popular (some eugenics programs, including sterilization programs, continued quietly for many more decades, however). Many eugenicists of the prev...

Enzyme

...important to note that, as with all catalysts, all reactions catalyzed by enzymes must be 'spontaneous' (contai...long as the net free energy from the total of both reactions is negative. Enzymes are necessary within biological cells to control molecular shapes and becau...

Warm-blooded

...e and you will now have all your internal chemical reactions functioning at their best. This means that you can think, move, digest, etc with your best possible speed and efficiency. Warm blooded animals warm themselves by digesting food. The disadvantage of being warm blooded is that you must always have la...

Diffusion

... of turbulent fluid motion rather than chemical reactions or the application of external force . In cell biology , diffusion is described as a form of " passive transport ", by which substances cross membranes . Contents showTocToggle("show","hide") 1 Background 2 Types of diffusion ...

Cytosol

...ors and ribosomes . In prokaryotes, all chemical reactions take place in the cytosol. In eukaryotes , the cytosol contains the cell organelles . In plants, the amount of cytosol can be reduced due to the large tonoplast (central vacuole ) that takes up most of the cell interior volume. The cytosol is n...

Cytoplasm

...ubstances indispensable to life. Vital metabolic reactions take place here, for example anaerobic glycolysis and proteic synthesis . See also : microtubules , vesicle...

Citric acid cycle

...le, or the Krebs cycle ) is a series of chemical reactions of central importance in all living cells that ...nds such as certain amino acids , and some of its reactions are therefore important even in cells performing fermentation . Contents showTocToggle("show"...

Chromatography

...d speed TLC is often used for monitoring chemical reactions and for the qualitative analysis of reaction products. TLC plates are made by mixing the adsorbent with a small amount of inert binder like calcium sulfate (gypsum) and water, spreading the a thick slurry on the carrier, drying the plate, and a...

Cell metabolism

...extremely complex sequences of controlled chemical reactions called metabolic pathways . Contents showT...e energy and reducing power. On balance, catabolic reactions are normally exothermic . Carbohydrate catabolism Main article: Carbohydrate catabolism C...

Cell nucleus

...i have two primary functions: to control chemical reactions within the cytoplasm and to store information ...s and the cytoplasm, while separating the chemical reactions taking place in cytoplasm from reactions happening within the nucleus. The outer membrane is continu...

Carbon fixation

... there is a turn in the Calvin cycle in the dark reactions of photosynthesis. These three carbon dioxide molecules undergo the chemical reactions in the Calvin cycle. The end result is that there is a net output of a single G3P ; and in two tur...

Brain

...s of a body, interpret those signals and formulate reactions based on prior experiences and on physical needs. A similarly extensive nerve network delivers signals from a brain to control muscles throughout a body. Sensory input is processed by the brain to recognize danger, find food, and identify potential...

Calvin cycle

...Calvin-Benson cycle ) is a series of biochemical reactions taking place in the chloroplasts of photosynthe...a, Berkeley . It is one of the light-independent reactions and occurs in the stroma . During photosynthesis, light energy has been converted into chemical...

Biochemistry

... . Biochemists study the molecules and chemical reactions catalyzed by enzymes that take place in all living organisms . See the article on molecular biology for a diagram and description of the interrelationship between biochemistry, molecular biology, and genetics . Biochemistry is the study...

ATPase

...(in most cases) harnesses to drive other chemical reactions that would not otherwise occur. This process is widely used in all known forms of life . Some such enzymes are integral membrane proteins (anchored within biological membranes ), and move solutes across the membrane. (These are called tran...

ATP synthase

...ne; the CF 1 -part sticks into stroma , were dark reactions of photosynthesis ( Calvin cycle ) and ATP synthesis take place. The overall structure and the catalytic mechanism of the chloroplast ATP synthase are almost the same as those of the mitochondrial enzyme. However, in chloroplasts the protonmotive ...

Amino acid

...he body from other compounds through chemical reactions , but instead must be taken in with food. In humans , the essential amino acids are lysine , leucine , isoleucine , methionine , phenylalanine , threonine , tryptophan , valine , and (in children) histidine and arginine . General stru...

Amine

... The pairs of dots on the N atoms in the chemical reactions shown in this article represent the lone electron ...ernary ammonium salts . The X shown in the above reactions can also be some other leaving group forming a corresponding acid or anion. Because inversion of ...

Adenosine triphosphate

...hem and ATP, energy can be easily transferred with reactions such as those catalyzed by nucleoside diphosphokinase : Energy is released when hydrolysis of the phosphate-phosphate bonds is carried out. This energy can be used by a variety of enzymes , motor proteins , and transport proteins to carry ou...

Activation energy

...l to the activation for that reaction. Multi-stage reactions involve a number of transition points, here the activation energy is equal to the one requiring the most energy. After this time either the molecules move apart again with original bonds reforming, or the bonds break and new products form. This is po...