Living systems are made up of various complex biomolecules like carbohydrates, proteins, nucleic acids, lipids, etc. Carbohydrates are optically…

Living systems are made up of various complex biomolecules like carbohydrates, proteins, nucleic acids, lipids, etc. Carbohydrates are optically active polyhydroxy aldehydes or ketones or molecules which provide such units on hydrolysis. They are broadly classified into three groups - monosaccharides, oligosaccharides and polysaccharides. Monosaccharides are held together by glycosidic linkages to form disaccharides like sucrose, maltose or polysaccharides like starch and cellulose. Another biomolecule : proteins are polymers of $\displaystyle \alpha$-amino acids which are linked by peptide bonds. Ten amino acids are called essential amino acids. Structure and shape of proteins can be studied at four different levels i.e. primary, secondary, tertiary and quaternary, each level being more complex than the previous one. Answer the following questions :

What is the difference between a glycosidic linkage and peptide linkage ?

Which amino acids are called essential amino acids ?

What are the common types of secondary structures of proteins ? Write any two forces which stabilise the secondary and tertiary structures of protein.

Define denaturation of protein with an example. During denaturation which structures of protein lose their biological activity ?