National Academy of Sports Medicine (NASM) Certified Personal Trainer (CPT) Practice Exam

Which carbohydrate combines with glucose to form lactose?

1. Galactose

2. Fructose

3. Maltose

4. Sucrose

The correct answer is: Galactose

Lactose is a disaccharide sugar composed of two monosaccharides: glucose and galactose. When glucose combines with galactose, it forms lactose, which is commonly known as milk sugar. This combination is facilitated by a glycosidic bond. Galactose is specifically the carbohydrate that, when paired with glucose, results in the formation of lactose, making it the correct answer. Other carbohydrates mentioned in the choices do not contribute to the formation of lactose. Fructose is a monosaccharide that pairs with glucose to create sucrose, maltose is formed from two glucose molecules, and sucrose is a different disaccharide composed of glucose and fructose. Understanding the specific pairings of monosaccharides is essential for grasping how various carbohydrates are structured and function in nutrition.