question_answer

Lactose is made of

A) \[\alpha -\]D-glucose only

B) \[\alpha -\]D-glucose and\[\beta -\]D-glucose

C) \[\alpha -\]D-galactose and\[\beta -\]D-glucose

D) \[\beta -\]D-galactose and\[\beta -\]D-glucose

E) \[\beta -\]D-galactose and\[\beta -\]D-glucose

Correct Answer: D

Solution :

Lactose (milk sugar) is a disaccharide, obtained by the   condensation   of   one   molecule   of \[\beta -\]D-galactopyranose   and   one   molecule   of\[\beta -\] D-glucopyranose.