1. Cellulose, starch, and glycogen are very similar, yet very different. Describe the process by which each of these molecules is formed. Why does the subtle difference in how the simple sugar monomers are bonded in starch and cellulose affect how the two molecules are used?
Cellulose is built from glucose molecules bonded covalently together through a process known as hydrolysis. Hydrolysis is a chemical process in which a molecule of water is added to a substance. Each alternating glucose ring of the cellulose molecule is flipped over and the water molecule (H2O) has been split out leaving an oxygen molecule between each ring. This chain or ribbon (the cellulose molecule) will continue for 3,000 to 5,000 glucose units.
Starch is a polysaccharide comprising glucose monomers joined in α 1,4 linkages. Glucose compounds are joined together in a chain of molecules by a process of dehydration synthesis. Dehydration refers to the removal of that water molecule. Synthesis refers to the building or "putting together" process. Through this process, hydrogen (H) and hydroxide (OH) ends are removed and joined separately to make water. Multiple bonds of hundreds of glucose can form complex sugars and polysaccharides such as starch.
Glycogenesis is the formation of glycogen. Glycogen is the primary carbohydrate stored in the liver and muscle cells of animals which is from glucose. Glycogenesis takes place when blood glucose levels are sufficiently high to allow excess glucose to be stored in liver and muscle cells. Glycogenesis is stimulated by the hormone insulin. Insulin facilitates the uptake of glucose into muscle cells, though it is not required for the transport of glucose into liver cells. Insulin has profound effects on glucose metabolism in liver cells which stimulates glycogenesis.
Starch and cellulose are two very similar polymers. In fact, they are both made from the same monomer, glucose, and have the same glucose-based repeat units. There is only...
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