Question

Name some monosaccharides, disaccharides, and polysaccharides, and state some general functions of each. What is the most common subunit for polysaccharides? (pages \(34-38\) )

Short answer

Monosaccharides, such as glucose, fructose, and galactose, function as immediate energy sources and building blocks for complex carbohydrates. Disaccharides, like sucrose, lactose, and maltose, provide energy and are used for transport and storage in plants. Polysaccharides, including starch, glycogen, cellulose, and chitin, serve as storage molecules or structural components in organisms. The most common subunit for polysaccharides is glucose, found in starch, glycogen, and cellulose.

Step-by-step solution

Monosaccharides

Monosaccharides are simple sugars, consisting of a single sugar unit. Examples of monosaccharides include glucose, fructose, and galactose. These sugars function as an immediate source of energy for cells, with glucose being the primary energy source for most organisms. They also serve as building blocks for more complex carbohydrates.

Disaccharides

Disaccharides are formed when two monosaccharides join together through glycosidic linkage (a covalent bond). Examples of disaccharides are: - Sucrose (table sugar) - formed when glucose and fructose are joined together - Lactose (milk sugar) - composed of glucose and galactose - Maltose (malt sugar) - formed from two glucose units Like monosaccharides, disaccharides can also function as a source of energy for cells. They are also commonly used for transport and storage of energy molecules in plants.

Polysaccharides

Polysaccharides are complex carbohydrates formed by multiple monosaccharide units joined together through glycosidic linkages. There are several examples of polysaccharides, each with specific functions: - Starch: a storage polysaccharide formed by glucose monomers, primarily found in plants. - Glycogen: similar to starch but found in animals, glycogen serves as a storage molecule for glucose, particularly in the liver and muscles. - Cellulose: a structural polysaccharide composed of glucose molecules, forming the main component of plant cell walls. - Chitin: another structural polysaccharide, made up of modified glucose molecules, that functions in the exoskeleton of arthropods and cell walls of some fungi.

The most common subunit for polysaccharides

The most common subunit for polysaccharides is glucose, as it can be found in starch, glycogen, and cellulose, which are some of the most abundant polysaccharides in nature.