Which of the following disaccharide compounds are described correctly?

A) Maltose: glucose and glucose joined by a β-1,4-glycosidic bond

B) Sucrose: galactose and fructose joined by an α-1,β-2-glycosidic bond

C) Lactose: galactose and glucose connected by an α-1,4-glycosidic bond

D) Lactose: galactose and glucose connected by a β-1,4-glycosidic bond

Click to reveal answer

Disaccharides are chemical compounds created when two

monosaccharides are joined covalently.

Answer D is correct because lactose is formed by the joining of galactose and

glucose by a β-1,4-glycosidic bond. For this reason, answer C is incorrect. There is

no α-1,4-glycosidic bond in lactose.

Answer A is incorrect because maltose requires an α-1,β-2-glycosidic bond, rather

than a β-1,4-glycosidic bond, between glucose and glucose.

If you have any questions or see any issues with this page, please get in touch with matthew.russell@inspiraadvantage.com

Day 112 MCAT Practice Question