Question

When the OH group at anomeric carbon lies on the same side as that of the OH group on C3 carbon, it is known as ______

(a) α-glucose

(b) β-glucose

(c) D-glucose

(d) (+)-glucose

I had been asked this question in final exam.

My doubt is from Biomolecules Carbohydrates in portion Biomolecules of Chemistry – Class 12

Answer 1

Correct option is (b) β-glucose

To elaborate: The OH at C3 carbon always lies on the side opposite to that of OH at C2 and C4 carbon in all structures of glucose. When the OH of anomeric carbon lies on the same side as that of the C2 and C4 carbon Oh group, it is known as α-form. Else, it is β-form.