Starch consist of two components amylose and amylopectin

(i) Sucrose: D - glucose and D - fructose linked by α. - 1, 2 glycosidic bond.
(ii) Maltose: Two molecules of α. - D - glucose linked by α. - 1, 4 glycosidic bond.
(iii) Lactose: f3 - D - glucose and f3 - D galactose linked by β - 1, 4 glycosidic bond

(i) Enzymes are biocatalysts that catalyse a specific biochemical reaction.
(ii) They generally activate the reaction by reducing the activation energy by stabilising the transition state.
(iii) In a typical reaction, enzyme E binds with the substrate molecule reversibly to produce an enzyme substrate complex.
(iv) During this stage,the substrate is converted into product and the enzyme becomes free and is ready to bind to another substrate molecule.
\(\underset { Enzyme }{ E } +\underset { Substance }{ S } \longrightarrow \underset { Enzyme-substratecomplex }{ [ES] } \) 
[ES]➝E+P

At aqueous solution, the proton from carboxyl group can be transferred to the amino group of an amino acid leaving these groups with opposite charges. Despite having both positive and negative charges, this molecule is neutral and has amphoteric behaviour. These ions are called zwitter ions.

Zwitter ions behave as neutral molecules at pH isoelectric point.