Zwitterion: Definition, Structure and Applications (2023)

What is zwitterion?

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A zwitterion is oneMoleculeIt has positive and negative charges. A zwitterion is an ion or molecule containing an equal number of well-charged and wrongly-charged functional groups. It is also called a neutral ion or inner salt. Zwitterionic polymers are also available and contain active groups that are slightly charged. Zwitterion is amphoteric in nature and does not migrate into the during electrolysiscathode or anode.

Carga Zwitterion

α-amino acids are excellent examples of zwitterions. The amino group contains the positive charge while thecarboxylic acidgroup contains the negative charge. The α-amino acids are crystalline due to the formation of zwitterions.

Also read: Electrochemie

It forms a zwitterion when dissolved in an aqueous solution. For example, if R-CH-NH₂-COOH dissolves in aqueous solution, the oxygen atom accepts electrons from the hydrogen in the carboxyl group. This gives oxygen a negative charge and leads to the formation of H⁺ions this h⁺combines with a nitrogen lone pair to form NH₃⁺ions

zwitterion amino acid

Amino acids contain basic and acidic groups. Here, h.⁺binds to a lone nitrogen pair to form NH₃⁺ions that are basic while COO^-The ion leaves the acidic carboxylic acid group, resulting in the formation of the zwitterion.

Any compound containing acid and subcutaneous compounds can form a zwitterion form. Other examples include tricine, bicine, solid sulfamic acid, and alkaloids such as psilocybin.

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electrical disconnection point

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Zwitterion has an isoelectric point represented by pI, pH(I), IEP. This point is the pH at which the charge on the molecules is neutral. In general, the net charge of a molecule is strongly influenced by the pH of the environment.

In this case, by accepting electrons, the molecules become more positively charged in an acidic medium, while in a basic medium they are more negatively charged. when we lookamino acidsthe amino group is the most efficient proton acceptor and the carboxyl group is the most active proton donor.

Isoelectric point in amino acids

In addition, the solubility of a molecule at a given pH is affected by the pI value. At the given isoelectric point there would be less or no solubility in aqueous solutions. For this reason,PH valueThe point at which a molecule's zwitterion forms is called the cell site of that molecule. The isoelectric point affects various molecular structures, such as the dissolution of solutions.

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Calculation of the pH value

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The pl value of the zwitterion is calculated using the following formula.

\(pI = \frac{pKa_1 + pKa_2}{2}\)

Wo,

pI → isoelectric point.

Ö₁→ The acid equilibrium constant.

Ö₂→ The Basis Glide Weight Constant.

Application of zwitterion

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1. A zwitterion is widely used in the process of separating protein molecules by the SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) method. This is one of the most popular methods in molecular biology. They have great potential for use in various medical and biological fields.

Zwitterionic bioceramics in the biomedical field

2. Other popular applications include medical implants, drug delivery, blood sensitive nerves, membrane dissection, and biopsies to prevent bacterial adhesions and biofilm formation.
3. In the marine industry zwitterionicpolymersThey are used to prevent underwater organisms from forming algae or moss on ships and docks.

also read:Daniel Handy

things to remember

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• A zwitterion is an active group molecule where at least one has a positive electrical charge and the other has a negative electrical charge.
• Amino acids are the most appropriate example of a zwitterion.
• Zwitterions provide strong hydration through electrostatic interactions with water molecules and provide a stronger barrier toAdsorption.
• Therefore, zwitterions are electrically neutral and will not migrate in an electric field.
• A zwitterion is widely used in the process of separating protein molecules by the SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) method.

also read:Nernst equation

sample questions

Question Give some other examples of a zwitterion.(2 points)

answer. Some other examples of zwitterions are trimethylglycine, psilocybin, cocamidopropyl betaine, etc.

Question Is lysine a zwitterion?(2 points)

or.L-lysine is produced in all eukaryotes, from yeast to individuals. An L-lysine zwitterion is an L-alpha amino acid zwitterion caused by the transfer of a carboxy proton to the amino group of L-lysine; prominent species at pH 7.3. As a human metabolite, it has a function.

Question Why do zwitterions have a high melting point?(2 points)

Question Write a short note about the zwitterion.(2 points)

or.A zwitterion is a molecule with at least two active groups: one positively charged and one negatively charged all the way to zero. Zwitterions can form from other molecules called ampholytes or amphoteric compounds and can act as both an acid and a base. Polyelectrolyte zwitterions contain either positively or negatively charged groups and the net charges are neutral.

Question How is a zwitterion formed?(2 points)

or.A zwitterion is a zwitterion formed by combining a carboxyl group with an amino group. As a result, it consists of a high proportion of amino acids. The carboxyl group in the zwitterion carries a negative charge while the amine group carries a positive charge.

Question Amino acids behave like salts and not like simple amines or carboxylic acids. Explain.(2 points)

Answer In an aqueous solution, the -COOH group of an amino acid loses a proton and the -NH group loses a proton.₂Group accepts a proton to form a zwitterion (salt).

Question When a protein in its native form undergoes a physical change, such as B. a temperature change, or a chemical change, such as. a pH change, denaturation of the protein occurs. Explain the reason.(2 points)

or.Due to physical or chemical changes, hydrogen bonding and other attractive forces are disrupted, the spheres unfold, and the helix unwinds to form a thread-like molecule. Therefore, the secondary and tertiary structure of the protein loses all or part of its biological activity. This is called protein denaturation.

Question The activation energy for the acid-catalyzed hydrolysis of sucrose is 6.22 kJ mol^-1, while hydrolysis is catalyzed by the enzyme sucrase. Explain.(2 points)

or.Enzymes are biocatalysts. They reduce the magnitude of the activation energy by providing alternative pathways. In the hydrolysis of sucrose, the enzyme sucrase reduces the activation energy by 6.22 kJ mol.^-1up to 2.15 kJ mol^-1. As a result, enzyme-catalyzed reactions proceed much faster than traditional chemical reactions using traditional catalysts.

Question How do you explain the presence of an aldehyde group in a glucose molecule?(3 points)

or.Glucose reacts with hydroxylamine to form a monoxime and adds a molecule of hydrogen cyanide to form cyanohydrin.

Hence, it contains a carbonyl group, which can be either an aldehyde or a ketone. On mild oxidation with bromine water, glucose yields gluconic acid, a six-carbon carboxylic acid.

This indicates that the carbonyl group present in glucose is an aldehyde group.

Question What are glycosidic bonds? In what kind of biomolecules are they present?(2 points)

Question Describe the terms D and L configuration used for amino acids with examples.(3 points)

Question How will you distinguish the first and second hydroxyl groups in glucose? Explain with reactions.(3 points)

or.Glucose in treatment with acetic anhydride in the presence of pyridine or with a few drops. H₂SO₄forms a pentaacetyl derivative, indicating the presence of 5-OH groups. Of these, one -OH group is primarily alcoholic (1°) and four (C2, C3, C4 and C5) -OH groups are secondary alcoholic (2°).