Enzymes are biological catalysts and activation energy is the minimum amount of energy required by the reactants for the reaction to take place. Enzymes increase the rate of chemical reactions while remaining unchanged by reducing the activation energy required for the reaction to proceed. Enzymes are made of proteins folded into complex shapes that allow smaller molecules to fit into them. These smaller molecules fit into the active site of an enzyme. The active site is where specific substrate molecules bind and the chemical reaction is carried out. The chemical structure and bonds between amino acids determine the shape of an active site. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay All metabolic pathways are controlled by enzymes. In metabolic pathways, the substrate is modified at each step to obtain the final product. Almost all metabolic pathways are reversible. Sometimes a specific substrate or enzyme is not available at a given point in a pathway, but the final product can still be made using an alternative pathway. Two types of metabolic pathways are anabolic and catabolic. Anabolic pathways require energy to transform small molecules into larger molecules. Catabolic pathways produce energy when large molecules are broken down into smaller molecules. Many factors affect enzyme activity. These include: temperature, pH, enzyme concentration, substrate concentration and the presence of inhibitors or activators. Keep in mind: this is just a sample. Get a personalized article from our expert writers now. Get a personalized test An inhibitor decreases the rate of an enzyme controlled reaction. Competitive inhibitors and noncompetitive inhibitors are two common types of inhibitors.Competitive inhibitors. Inhibitory molecules bind to the active site to prevent substrate molecules from binding to the active site. The molecular structure of competitive inhibitors is similar to that of the substrate and therefore can insert into the active site and block the substrate.Non-competitive inhibitors. The inhibitor reduces the activity of the enzyme and binds equally well to the enzyme whether or not it has already bound the substrate. The inhibitor can bind to the enzyme whether or not the substrate has already been bound, but if it has a higher affinity to bind to the enzyme in one state or another, it is called an mixed inhibitor. Works Cited Berg, JM, Tymoczko, JL, & Gatto, GJ (2020). Biochemistry (9th ed.). W. H. Freeman and Company. Nelson, D.L., Cox, M.M. (2020). Lehninger Principles of Biochemistry (8th ed.). W. H. Freeman and Company. Lodish, H., Berk, A., Zipursky, SL, et al. (2022). Molecular Cell Biology (9th ed.). W. H. Freeman and Company. Garrett, R.H. & Grisham, C.M. (2019). Biochemistry (6th ed.). Cengage Learning. Alberts, B., Johnson, A., Lewis, J. et al. (2019). Molecular biology of the cell (6th ed.). Garland Science. Cox, M.M., Nelson, D.L. (2021). Lehninger Principles of Biochemistry: Study Guide and Solutions Manual (7th ed.). W. H. Freeman and Company. Nelson, D.L., Cox, M.M. (2021). Lehninger principles of biochemistry: coursebook (7th ed.). W. H. Freeman and Company. Price, N.C., Stevens, L. (2020). Fundamentals of enzymology: the cellular and molecular biology of catalytic proteins. Oxford University Press. Cornish-Bowden, A. (2012). Fundamentals of Enzyme Kinetics (4th ed.). Wiley. Segel, I. H. (1993). Enzyme kinetics: behavior and analysis of enzyme systems at rapid equilibrium and steady state. Wiley.