What monosaccharide forms when the following polysaccharides are completely hydrolyzed? (a) starch, (b) glycogen, (c) cellulose

The profound understanding of monosaccharide formation begins with recognizing the basic building blocks of carbohydrates. Monosaccharides are the simplest form of carbohydrates and they include glucose, fructose, and galactose. These singular sugar molecules are the result of hydrolysis, a chemical process involving water to split complex sugars. Hydrolysis can be catalyzed by acids, bases, or enzymes, breaking the glycosidic bonds that connect sugar units in polysaccharides.

For instance, when you consume foods containing complex carbohydrates, your body employs specific enzymes to break them down into monosaccharides, mainly glucose, which is then absorbed by your body's cells for energy. The hydrolysis is crucial for your body to obtain energy from the food you consume.

Starch, a common polysaccharide found in plants, serves as a major energy reserve carbohydrate. It consists of two types of molecules: amylose and amylopectin. Both are polymers of glucose. During the process of hydrolysis, enzymatic reactions, primarily involving amylase enzymes, break down these polymers into glucose monomers.

Starch hydrolysis is a stepwise process where enzymes cut the glycosidic bonds between glucose units. The end product of complete hydrolysis is a pool of glucose molecules that the body can then utilize for producing energy, a crucial biological mechanism for maintaining cellular functions.

Similarly, glycogen is the storage form of glucose in animals and is found predominantly in the liver and muscle tissues. Its structure is highly branched, allowing for the rapid release of glucose when energy is needed. Glycogen breakdown, also known as glycogenolysis, involves enzyme-based hydrolysis.

The enzymes target the branched points and the linear sequences of glycogen, producing glucose-1-phosphate, which is then converted into glucose-6-phosphate. This glucose derivative can enter various metabolic pathways to provide energy for cellular activities, demonstrating the importance of glycogen breakdown in energy metabolism.

Cellulose is a polysaccharide that differs from starch and glycogen by the type of glycosidic linkage between glucose units. It's a major component of plant cell walls and provides structural support. Unlike starch and glycogen, cellulose is not soluble in water, and most animals, including humans, lack the enzyme to break down the beta-glycosidic bonds present in cellulose.

However, some herbivorous animals have specialized bacteria in their digestive systems that produce cellulase, the enzyme required for cellulose digestion. In these creatures, cellulose can be hydrolyzed into glucose units, illustrating a symbiotic relationship that enables them to extract energy from a substance that is indigestible to many other organisms.