Proteins are found to have two different types of secondary structures viz. α -helix and β - pleated sheet structure. α -helix structure of protein is stabilised by

(a) Peptide bonds

(b) Van der Waals forces

(c) Hydrogen bonds

(d) Dipole-dipole interactions

Insulin is a globular proteins.

Ionisation enthalpy increases in a period. Z dominates over screening effect (s) in a period as Z_eff. increases.

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Histidine is an essential amino acid

Lactose is a disaccharide which is formed by forming C? -C? glycosidic linkage between D-galactose and D- glucose.
Lactose - (Hydrolysis)-> D - galactose + D - glucose