Lactose

Definition

Lactose is a disaccharide sugar composed of two monosaccharides, glucose and galactose, commonly found in milk and dairy products. It serves as an important source of energy for many organisms, especially in early development, and is classified within the larger category of carbohydrates, specifically as a non-reducing sugar due to its unique structure.

5 Must Know Facts For Your Next Test

1. Lactose makes up about 2-8% of milk's composition, providing energy and contributing to its sweetness.
2. Lactose intolerance occurs when individuals lack sufficient lactase to properly digest lactose, leading to gastrointestinal discomfort.
3. Lactose can be fermented by certain bacteria, which is how products like yogurt and cheese are made, resulting in lower lactose content.
4. Lactose has a lower sweetness level compared to sucrose (table sugar), making it less sweet in flavor despite being a sugar.
5. In addition to milk, lactose is also present in other dairy products like cheese and ice cream, though the concentration varies.

Review Questions

• How does the structure of lactose contribute to its classification within carbohydrates?
  • Lactose is classified as a disaccharide due to its composition of two monosaccharides: glucose and galactose. Its structure connects these two sugars through a glycosidic bond, which affects how it is digested and metabolized. This unique structure differentiates it from other carbohydrates, such as polysaccharides or other disaccharides like sucrose and maltose.
• Discuss the role of lactase in lactose digestion and what happens when there is a deficiency in this enzyme.
  • Lactase is essential for breaking down lactose into its component sugars, glucose and galactose, which can then be absorbed into the bloodstream. When there is a deficiency of lactase, lactose remains undigested in the gut, leading to symptoms associated with lactose intolerance such as bloating, gas, and diarrhea. This impacts dietary choices for individuals who are lactose intolerant as they may need to avoid dairy or consume lactose-free alternatives.
• Evaluate the implications of lactose fermentation in dairy products and how this process affects lactose content.
  • Lactose fermentation involves the action of specific bacteria that convert lactose into lactic acid during processes like yogurt or cheese production. This fermentation reduces the overall lactose content of these products, making them more tolerable for individuals who are lactose intolerant. Additionally, the presence of beneficial bacteria contributes to the probiotic qualities of fermented dairy products, enhancing gut health while altering their flavor profile.

Related terms

Galactose: A monosaccharide that, when combined with glucose, forms lactose; it is one of the two components of lactose.

Maltose: Another type of disaccharide formed from two glucose units; it is important for understanding the variety of carbohydrate structures.

Lactase: An enzyme produced in the small intestine that breaks down lactose into glucose and galactose, facilitating its digestion.