Molecular Science P. 60-69

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Stereoisomerism vs. Constitutional

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Stereoisomers are isomeric molecules that have the same molecular formula and sequence of bonded atoms (constitution), but that differ only in the three-dimensional orientations of their atoms in space.

This contrasts with structural isomers, which share the same molecular formula, but the bond connections or their order differs. By definition, molecules that are stereoisomers of each other represent the same structural isomer.

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Triglyceride

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(TG, triacylglycerol, TAG) is an ester derived from glycerol and three fatty acids.

As a blood lipid, it helps enable the bidirectional transference of adipose fat and blood glucose from the liver. There are many triglycerides: depending on the oil source, some are highly unsaturated, some less so

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Vitamin E

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As an antioxidant, vitamin E acts as a peroxyl radical scavenger, preventing the propagation of free radicals in tissues, by reacting with them to form a tocopheryl radical, which will then be reduced by a hydrogen donor (such as vitamin C) and thus return to its reduced state.[26] As it is fat-soluble, it is incorporated into cell membranes, which protects them from oxidative damage. Vitamin E has also found use as a commercial antioxidant in ultra high molecular weight polyethylene (UHMWPE) used in hip and knee replacements, to help resist oxidation.

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Vitamin A

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In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal.

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Vitamin D

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Responsible for enhancing intestinal absorption of calcium, iron, magnesium, phosphate and zinc. As vitamin D is synthesized in adequate amounts by most mammals exposed to sunlight, it is not strictly a vitamin, and may be considered a hormone as its synthesis and activity occur in different locations.

Vitamin D has a significant role in calcium homeostasis and metabolism.

Very few foods contain vitamin D, synthesis of vitamin D (specifically cholecalciferol D3) in the skin is the major natural sources of the vitamin. Dermal synthesis of vitamin D from cholesterol is dependent on sun exposure (specifically UV-B radiation). Vitamin D from the diet or dermal synthesis from sunlight is biologically inactive, activation requires enzymatic conversion (hydroxylation) in the liver and kidney. Evidence indicates the synthesis of vitamin D from sun exposure is regulated by a negative feedback loop that prevents toxicity.

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Phosphate

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In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid

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Esters (Essigäther)

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In chemistry, esters are chemical compounds derived from an acid in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group.

Esters are generally derived from a carboxylic acid and an alcohol.

Esters comprise most naturally occurring fats and oils, which are fatty acid esters of glycerol. Esters with low molecular weight are commonly used as fragrances and found in essential oils and pheromones. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties, while polyesters are important plastics, with monomers linked by ester moieties.

The word 'ester' was coined in 1848 probably as a contraction of the German Essigäther, "acetic ether/alcolohol".

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Enantiomer

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One of two stereoisomers that are non-superimposable mirror images of each other

Opposite orientation

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Epimers

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Epicenter of medicinal problems:)

Isomer

In stereochemistry, epimer refers to one of a pair of stereoisomers. They are very closely related structures. The two isomers differ in configuration at only one stereogenic center. All other stereocenters in the molecules, if any, are the same in each.

Front 10

Hydrosoluble vitamins

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B1 B2 B...., C, PP, Biotin, Pantotenic acid, folic acid

B12 only in animals, produced by microorganisms

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Liposoluble vitamins

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A

D

E

K

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Vitamin K

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Vitamin K refers to a group of structurally similar, fat-soluble vitamins the human body needs for complete synthesis of certain proteins that are required for blood coagulation, and also certain proteins that the body uses to manipulate binding of calcium in bone and other tissue.

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Koagulation

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Coagulation or clotting is the process by which blood changes from a liquid to a gel. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair.

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Pp

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Nicain

Front 15

Photo-Autotroph

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Obtaining energy from light

Phototrophs (Gr: φῶς, φωτός = light, τροϕή = nourishment) are the organisms that carry out photon capture to acquire energy. They use the energy from light to carry out various cellular metabolic processes.

Most of the well-recognized phototrophs are autotrophic, also known as photoautotrophs, and can fix carbon. They can be contrasted with chemotrophs that obtain their energy by the oxidation of electron donors in their environments. Photoautotrophs are capable of synthesizing their own food from inorganic substances using light as an energy source. Green plants and photosynthetic bacteria are photoautotrophs.

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Chemo-Autotroph

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Chemoautotrophs take energy from food, not from the sun.

(Gr: Chemo (χημία) = chemical, auto (αὐτός) = self, troph (τροφιά) = nourishment) in addition to deriving energy from chemical reactions, synthesize all necessary organic compounds from carbon dioxide.

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Oligosaccharides (3-10) vs?

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Polysaccharides (more than 3)

Both not sweet

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Inert

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Not chemically reactive

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5 atom rings

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Fünf - furanosic

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5 atom rings

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Fünf - furanosic

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6 atom rings

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Pyranosic

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Racemic mixture

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In chemistry, a racemic mixture, or racemate /reɪˈsimeɪt/, is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule.

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Racemic mixture

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In chemistry, a racemic mixture, or racemate /reɪˈsimeɪt/, is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule.

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Peptidic bond

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Chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other, releasing a molecule of water (H2O). This is a dehydration synthesis reaction (also known as a condensation reaction), and usually occurs between amino acids.

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Triglycerides

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Abundant in fat. In production used when around 15% (isolated)

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Organic redox

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In organic chemistry oxidations and reductions are different from ordinary redox reactions because many reactions carry the name but do not actually involve electron transfer in the electrochemical sense of the word.

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Organic redox

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In organic chemistry oxidations and reductions are different from ordinary redox reactions because many reactions carry the name but do not actually involve electron transfer in the electrochemical sense of the word.

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Oxidation number

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oxidation number -4 for alkanes,

oxidation number -2 for alkenes, alcohols, alkyl halides, amines,

oxidation number 0 for alkynes, ketones, aldehydes, geminal diols,

oxidation number +2 for carboxylic acids, amides, chloroform and

oxidation number +4 for carbon dioxide, tetrachloromethane.

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Oxidation state

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The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.

For pure elements, the oxidation state is zero.

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Oxidation state

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The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.

For pure elements, the oxidation state is zero.

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Oxidation reaction

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Many oxidations involve removal of hydrogen atoms from the molecule

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Redox potential

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reduction potential. Measurement for water and food quality.

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Oxidation state

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The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.

For pure elements, the oxidation state is zero.

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Oxidation reaction

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Many oxidations involve removal of hydrogen atoms from the molecule

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Redox potential

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reduction potential. Measurement for water and food quality.

Front 36

Ketoses can isomerize into aldoses

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Change

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Oxidation state

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The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.

For pure elements, the oxidation state is zero.

Front 38

Oxidation reaction

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Many oxidations involve removal of hydrogen atoms from the molecule

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Redox potential

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reduction potential. Measurement for water and food quality.

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Ketoses can isomerize into aldoses

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Change

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Reducing sugar

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A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerism. The aldehyde functional group allows the sugar to act as a reducing agent, for example in the Tollens' test or Benedict's reagent, or the Maillard reaction, important in the browning of many foods. The cyclic hemiacetal forms of aldoses can open to reveal an aldehyde and certain ketoses can undergo tautomerization to become aldoses. However, acetals, including those found in polysaccharide linkages, cannot easily become free aldehydes.

Front 42

Oxidation state

Back 42

The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.

For pure elements, the oxidation state is zero.

Front 43

Oxidation reaction

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Many oxidations involve removal of hydrogen atoms from the molecule

Front 44

Redox potential

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reduction potential. Measurement for water and food quality.

Front 45

Ketoses can isomerize into aldoses

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Change

Front 46

Reducing sugar

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A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerism. The aldehyde functional group allows the sugar to act as a reducing agent, for example in the Tollens' test or Benedict's reagent, or the Maillard reaction, important in the browning of many foods. The cyclic hemiacetal forms of aldoses can open to reveal an aldehyde and certain ketoses can undergo tautomerization to become aldoses. However, acetals, including those found in polysaccharide linkages, cannot easily become free aldehydes.

Front 47

Open chain compound

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Non cyclic

Front 48

Oxidation state

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The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.

For pure elements, the oxidation state is zero.

Front 49

Oxidation reaction

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Many oxidations involve removal of hydrogen atoms from the molecule

Front 50

Redox potential

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reduction potential. Measurement for water and food quality.

Front 51

Ketoses can isomerize into aldoses

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Change

Front 52

Reducing sugar

Back 52

A reducing sugar is any sugar that either has an aldehyde group or is capable of forming one in solution through isomerism. The aldehyde functional group allows the sugar to act as a reducing agent, for example in the Maillard reaction, important in the browning of many foods. The cyclic hemiacetal forms of aldoses can open to reveal an aldehyde and certain ketoses can become aldoses.

A sugar is classified as a reducing sugar only if it has an open-chain form with an aldehyde group or a free hemiacetal group.

Monosaccharides which contain an aldehyde group are known as aldoses, and those with a ketone group are known as ketoses. The aldehyde can be oxidized via a redox reaction in which another compound is reduced. Thus, a reducing sugar is one that reduces certain chemicals. Sugars with ketone groups in their open chain form are capable of isomerizing via a series of tautomeric shifts to produce an aldehyde group in solution. Therefore, ketone-bearing sugars like fructose are considered reducing sugars but it is the isomer containing an aldehyde group which is reducing since ketones cannot be oxidized without decomposition of the sugar. This type of isomerization is catalyzed by the base present in solutions which test for the presence of aldehydes. Aldoses or aldehyde-bearing sugars are reducing also because during oxidation of aldoses, there are certain oxidizing agents that are reduced.

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Open chain compound

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Non cyclic

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Straight chain compound

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Like lipids, not cyclic or carb like

Front 55

Natural form sugars

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Biological systems tend to recognize D-aldoses more than L-aldoses.

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Natural form sugars

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Biological systems tend to recognize D-aldoses more than L-aldoses.

Front 57

D L nomenclature

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The 'D-' and 'L-' prefixes are also used with other monosaccharides, to distinguish two particular stereoisomers that are mirror-images of each other. For this purpose, one considers the chiral carbon that is furthest removed from the C=O group. Its four bonds must connect to -H, -OH, -C(OH)H, and the rest of the molecule. If the molecule can be rotated in space so that the directions of those four groups match those of the analog groups in D-glyceraldehyde's C2, then the isomer receives the 'D-' prefix. Otherwise, it receives the 'L-' prefix.

In the Fischer projection, the 'D-' and 'L-' prefixes specifies the configuration at the carbon atom that is second from bottom: 'D-' if the hydroxyl is on the right side, and 'L-' if it is on the left side.

Note that the 'D-' and 'L-' prefixes do not indicate the direction of rotation of polarized light, which is a combined effect of the arrangement at all chiral centers. However, the two isomers will always rotate the light in opposite directions, at the same rate.

Front 58

Cyclic is the predominant form

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A monosaccharide often switches from the acyclic (open-chain) form to a cyclic form, through a nucleophilic addition reaction between the carbonyl group and one of the hydroxyls of the same molecule. The reaction creates a ring of carbon atoms closed by one bridging oxygen atom. The resulting molecule has an hemiacetal or hemiketal group, depending on whether the linear form was an aldose or a ketose. The reaction is easily reversed, yielding the original open-chain form.

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Cyclic is the predominant form

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A monosaccharide often switches from the acyclic (open-chain) form to a cyclic form, through a nucleophilic addition reaction between the carbonyl group and one of the hydroxyls of the same molecule. The reaction creates a ring of carbon atoms closed by one bridging oxygen atom. The resulting molecule has an hemiacetal or hemiketal group, depending on whether the linear form was an aldose or a ketose. The reaction is easily reversed, yielding the original open-chain form.

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Rancidity

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Specifically, it is the hydrolysis and/or autoxidation of fats into short-chain aldehydes and ketones which are objectionable in taste and odor.[1] When these processes occur in food, undesirable odors and flavors can result. In some cases, however, the flavors can be desirable (as in aged cheeses).

Rancidification can also detract from the nutritional value of food, and some vitamins are highly sensitive to degradation.

Front 61

Vitamins B

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B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism. Though these vitamins share similar names, research shows that they are chemically distinct vitamins that often coexist in the same foods. In general, supplements containing all eight are referred to as a vitamin B complex.

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Nach Feuerelement (heisse Pfanne)

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Erde

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Nach Feuerelement (heisse Pfanne)

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Erde

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Nach Erde (Öl)

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Metall (Gewürz getrocknet)

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Nach Feuerelement (heisse Pfanne)

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Erde

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Nach Erde (Öl)

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Metall (Gewürz getrocknet)

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Nach Metall

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Wasser (Salz)

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Nach Feuerelement (heisse Pfanne)

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Erde

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Nach Erde (Öl)

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Metall (Gewürz getrocknet)

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Nach Metall

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Wasser (Salz)

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Nach wasser / Salz

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Holz (Sauer, Zitrone)

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Nach Feuerelement (heisse Pfanne)

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Erde

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Nach Erde (Öl)

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Metall (Gewürz getrocknet)

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Nach Metall

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Wasser (Salz)

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Nach wasser / Salz

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Holz (Sauer, Zitrone)

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Nach Holz

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Feuer (zwiebel Chicoree etc.) dann Erde: Gemüse

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Structure protein

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Primary structure: the amino acid sequence. A protein is a polyamide.

Secondary structure: regularly repeating local structures stabilized by hydrogen bonds. The most common examples are the alpha helix, beta sheet and turns. Because secondary structures are local, many regions of different secondary structure can be present in the same protein molecule.

Tertiary structure: the overall shape of a single protein molecule; the spatial relationship of the secondary structures to one another. Tertiary structure is generally stabilized by nonlocal interactions, most commonly the formation of a hydrophobic core, but also through salt bridges, hydrogen bonds, disulfide bonds, and even posttranslational modifications. The term "tertiary structure" is often used as synonymous with the term fold. The tertiary structure is what controls the basic function of the protein.

Quaternary structure: the structure formed by several protein molecules (polypeptide chains), usually called protein subunits in this context, which function as a single protein complex.