Amino Acids Ppt

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AMINO ACIDS

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Roles of Amino Acids

building blocks of proteins intermediates in metabolism.

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In the structure , R represents a side-chain specific to each amino acid. The carbon atom next to the carboxyl group is called the carbon and amino acids with a side-chain bonded to this carbon are referred to as alpha amino acids

In the alpha amino acids, the carbon is a chiral carbon atom, with the exception of glycine. In amino acids that have a carbon chain attached to the carbon (s the carbons are labeled in order as , , , , and so on. In some amino acids, the amine group is attached to the or -carbon, and these are therefore referred to as beta or gamma amino acids.

Physiologic pH.

Carboxyl group is dissociated = negatively charged ( Carboxylate ion ( -COO - ), and The Amino group is protonated ( -NH3 + ).

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The nature of the side chains ultimately dictates the role an amino acid plays in a protein.

Classification

A. Amino acids with Nonpolar side chains B. Amino acids with Uncharged Polar side chains C. Amino acids with acidic side chains D. Amino acids with basic side chains

A. Amino acids with non polar side chains oily or lipid like property Hydrophobic interactions Does not participate in hydrogen or ionic bonds Proline- imino group

B. Amino acids with uncharged polar chains

Contain hydroxyl group Participates in hydrogen bond formation The side chains of asparagine and glutamine each contain a carbonyl group and an amide group

C. Amino acids with acidic side chains

Proton donors Negatively charged

D. Amino Acids with basic side chains

Proton acceptors Positively charged

Unique first letter Abbreviations cysteineand symbols Cys C1. . . . . . .

Histidine- His Isoleucine-Ile Methionine- Met Serine Ser Valine- Val

H I M S V

2. Most commonly occuring amino Abbreviations acids have priority and symbols Ala Alanine A

Glycine - Gly G Leucine -Leu L Proline Pro P Threonine Thr T

3. Similar sounding namesAbbreviations sound like theSome one letter symbols amino and symbols acid they represent:

Arginine- Arg - R ( aRginine) Asparagine- Asn- N ( contains N) Aspartate-Asp- D ( asparDic) Glutamate- Glu-E (glutEmate) Glutamine Gln-Q (Q-tamine) Phenylalanine-Phe-F (Fenylalanine)

3. Similar sounding namesAbbreviations sound like theSome one letter symbols amino and symbols acid they represent:

Tyrosine- Tyr - Y ( tYrosine) Tryptophan- Trp- W (double ring in the molecule)

4.Letter close Abbreviations to initial letter: and symbols

Aspartate or asparagine- Asx- B Glutamate or glutamine- Glx Z Lysine Lys K ( near L ) Undetermined amino acid - X

The carboxyl and amino groups interact resulting in the transfer of proton from carboxyl group to amino group. Thus the amino acid exists in ionised form known as zwitter ion. .

At pH between 2.2 and 9.4, the predominant form adopted by -amino acids contains a negative carboxylate and a positive ammonium group, so has net zero charge

Below pH 2.2, the predominant form will have a neutral carboxylic acid group and a positive -ammonium ion (net charge +1), and above pH 9.4, a negative carboxylate and neutral -amino group (net charge -1)

At a certain hydrogen ion concentration (pH), the dipolar ion exists as a neutral ion and does not migrate to either electrode. This pH is known as the isoelectric point

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Amino acid deficiency

Weak immune system Loss of antibody production Fatigue Depression and mood issues Inefficient Digestive System

They join together to form short polymer chains called peptides Or longer chains called either polypeptides or proteins.

Process of translation Ribozyme called ribosome

These polymers are linear and unbranched, with each amino acid within the chain attached to two neighboring amino acids. The process of making proteins is called translation and involves the step-by-step addition of amino acids to a growing protein chain by a ribozyme that is called a ribosome. The order in which the amino acids are added is read through the genetic code from an mRNA template, which is a RNA copy of one of the organism's genes.

Peptide bond

As both the amine and carboxylic acid groups of amino acids can react to form amide bonds, one amino acid molecule can react with another and become joined through an amide linkage. This polymerization of amino acids is what creates proteins. This condensation reaction yields the newly formed peptide bond and a molecule of water. In

The amino acid is first activated by attachment to a transfer RNA molecule through an ester bond.

This aminoacyl-tRNA is produced in an ATP-dependent reaction carried out by an aminoacyl tRNA synthetase.

This aminoacyl-tRNA is then a substrate for the ribosome, which catalyzes the attack of the amino group of the elongating protein chain on the ester bond.

] As a result of this mechanism, all proteins made by ribosomes are synthesized starting at their Nterminus and moving towards their C-terminus.