What are milk sugars, specifically lactose, made up of?

Lactose, commonly known as milk sugar, is a disaccharide composed of two simple sugar units: one molecule of glucose and one molecule of galactose. This combination distinguishes lactose from other sugars, such as sucrose, which is made up of glucose and fructose, or maltose, which consists of two glucose molecules.

Understanding the structure of lactose is essential in various contexts, particularly in nutrition and food science, as it influences digestibility and the body's ability to absorb it. Lactic acid fermentation processes and lactose intolerance, for example, arise from how lactose is processed in the digestive system. Thus, recognizing that lactose is formed from glucose and galactose is a fundamental aspect of the study of carbohydrates in food preparation and nutrition.