AMINOACID CHEMISTRY

​CHEMISTRY OF AMINO ACIDS
AND PROPERTIES OF AMINO ACID

​About 300 amino acids are present in the nature.
Only 20 are found in proteins - standard amino acids.

Fill in the Blanks

Amino acids are the

units from which proteins are formed.

​Arginine Guanidine group

Phenylanine and tyrosine Benzene group

Tryptophan Indole group

Histidine imidazole group

proline and hydroxyline imino group

Multiple Choice

Which of the following amino acids is classified as a branched chain amino acid?

• Glycine

• Alanine

• Valine

• Serine

Multiple Choice

Which amino acid has a side chain consisting of only a hydrogen atom?

• Alanine

• Glycine

• Valine

• Leucine

Multiple Choice

Which of the following amino acids contains a hydroxyl group in its side chain?

• Serine

• Methionine

• Phenylalanine

• Lysine

Multiple Select

Select all amino acids that have an amide group in their side chain.

• Asparagine

• Glutamine

• Threonine

• Arginine

Fill in the Blanks

Aspartic acid and glutamic acid are examples of mono amino dicarboxylic acids because their side chains contain

groups.

Multiple Choice

Which amino acid has an aromatic ring with a hydroxyl group attached?

• Tyrosine

• Phenylalanine

• Serine

• Methionine

Multiple Choice

Which of the following amino acids is classified as a heterocyclic amino acid?

• Tryptophan

• Alanine

• Serine

• Leucine

Multiple Choice

Which of the following amino acids have nonpolar (hydrophobic) side chains?

• Alanine

• Serine

• Aspartic Acid

• Glutamine

Multiple Choice

Which amino acid is classified as only ketogenic?

• Leucine

• Lysine

• Tyrosine

• Phenylalanine

Multiple Choice

Which of the following amino acids are found in collagen?

• Hydroxyproline

• Gamma carboxy glutamate

• Histidine

• Ornithine

Multiple Select

Which of the following are non protein α-amino acids?

• Ornithine

• DOPA

• β-Alanine

• Taurine

​PROPERTIES OF AMINO ACIDS

1. ​Physical property
   Solubility: most of the amino acids are soluble in water and insoluble in organic solvents
   
   2.Melting point: amino acid melt at higher temperature often above 200 degree celsius

   3.Amino acid may be sweet (Gyl, Ala, Val), Tasteless (Leu), bitter (Arg, Ile). Monosodium glutamate is a salt of glutamic acid

   it is employed as flavoring agent in food industry to increase the taste
   

Alpha carbon of each amino acid is attached to four different atoms/groups - asymmetric carbon atom. 

​ Amino acid- D and L

Open Ended

List any two examples of non protein non α-amino acids and mention their biological significance.

​•The mirror images  produced with reference to the alpha carbon atom (asymmetric carbon) , are called D and L isomers

•The L form occurs commonly in nature

•The D form occurs in some micro-organisms and  certain antibiotics.

•Amino group on right – D

•Amino group on left    – L

•

•which are mirror images of each other.

•These forms are known as    stereoisomer

•optical isomer – dextro & levorotatory

​Biuret reaction	​Peptide bond
​ninhydrin reaction	alpha amino acid​
​Xanthoproteic reaction	benzene ring​
​Millons reaction	Phenolic group​
Sakaguchi test ​	​Guanidino group (Arg)

​Colour reaction of proteins

Multiple Choice

Which amino acid is responsible for making hair curly?

• Cysteine

• Leucine

• Tryptophan

• Serotonin

Open Ended

What makes your hair curly, your muscles strong, and your brain work?