The four fundamental types of molecules are vital to living organisms, and they include carbohydrates, proteins, lipids and nucleic acids (Springer, & Holley, 2013). However, one of the types of molecules is an enzyme. An enzyme is a catalyst that is used to speed up the rate of chemical reaction. It works by reducing the activation energy. Given the four molecules found in living organisms, proteins are the only enzymes. The proteins consist of a group of amino acids, and they do the daily activities of the cell. As an enzyme, proteins make chemical bonds; they also make new molecules for cells. Other than speeding up the rate of reactions, proteins break the chemical bonds existing and recycle the molecules for cells.

One of the enzymes found in living organisms is enzyme amylase. Enzyme amylase is produced in salivary glands, pancreas and the small intestines of the living organisms. The enzyme is responsible for the breakdown of starch that passes through the mouth and also in the small intestines. The salivary glands found in the mouths of the living organisms make salivary amylase. Therefore, the breakdown of starch by the salivary amylase in the mouth acts as the starting point of the chemical reactions in a living organism (Edwards, Pfirrmann, & Edwards, 2009). Starch is composed of glucose molecules that are joined in long chains. The work of salivary amylase is to break down starch into a simple sugar. Similarly, given time and ideal conditions, enzyme amylase can catalyze the reaction by breaking down the bonds between two glucose molecules that are found in starch, and those that it comes into contact with. The cells found in the pancreas make the pancreatic amylase. The enzyme passes through the duct to reach the small intestines of a living organism. The work of pancreatic amylase is to complete the digestion process of the carbohydrates by producing small molecules of glucose. The glucose is then absorbed into the bloodstreams and carried throughout the body of a living organism.

The enzymes have different ways of catalyzing the chemical reactions. Therefore, enzymes can bind two molecules together or break the large molecules into smaller groups. They are selective and can speed up a specific reaction. The enzymes work with the molecules called the substrates that bind on its active sites (Springer, & Holley, 2013). However, the substrate-enzyme reaction is explained by two theories that include the lock-and-key model and induced-fit model. In the lock and key model, the reaction exhibits enzyme specificity. The shape of the active site of an enzyme is precisely designed to hold a specific substrate. On the other hand, in the induced fit model, both the active site and the substrate alter their shapes to fit perfectly together. The substrates will bind to the active site for the reaction to accelerates. The occurrence of the chemical reaction will result in new molecules that will separate themselves from the enzymes so that they catalyze other reactions. For example, the salivary amylase in the mouth will bind with the starch and catalyze hydrolysis. The result will be the production of maltose.

References

Edwards, G. I., Pfirrmann, C., & Edwards, G. I. (2009). E-Z biology. Hauppauge, N.Y: Barron’s Educational Series.

Springer, J. T., & Holley, D. (2013). An introduction to zoology: Investigating the animal world. Boston: Jones & Bartlett Learning.

 
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