Which of the following reactions of glucose can be explained only by its cyclic structure? 

(a) Glucose forms pentaacetate. 

(b) Glucose reacts with hydroxylamine to form an oxime. 

(c) Pentaacetate of glucose does not react with hydroxylamine. 

(d) Glucose is oxidised by nitric acid to gluconic acid.

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