Basic Sugar Types: Monosaccharides and Disaccharides

Definition: Monosaccharides are the most basic units of carbohydrates, also known as simple sugars. They cannot be hydrolyzed into simpler carbohydrate units.
Examples Mentioned:
- Glucose: Identified as the main sugar. Glucose is a crucial energy source for living organisms and is a fundamental component in many biological pathways. Students often recognize its importance as blood sugar.
- Fructose: Another significant monosaccharide. Fructose is commonly found in fruits, honey, and many root vegetables. It is often referred to as "fruit sugar." The instructor clarified its spelling as " $F-R-U-C-T-O-S-E$ " and noted it is generally found in what we commonly call "sugar."

Definition: Disaccharides are formed when two monosaccharide units are joined together by a glycosidic bond. They are more complex than monosaccharides but can be broken down (hydrolyzed) into their constituent simple sugars.
Examples Mentioned:
- Lactose: Explicitly identified as a disaccharide, distinguishing it from monosaccharides like glucose and fructose. Lactose is commonly known as "milk sugar" and is composed of one glucose molecule and one galactose molecule joined together.

It is crucial to differentiate between monosaccharides (single sugar units like glucose and fructose) and disaccharides (double sugar units like lactose). This classification helps in understanding their different roles in nutrition and metabolism, as well as their structural complexity.