Grade 12 Enzymes PDF

Enzymes Week 9  Metabolism These are various chemical processes and chemical reactions happening in cells,  Metabolic Pathway It refers to the process of metabolism which starts with a molecule as a starting material then ends up with a product which will be utilize...

Enzymes Week 9  Metabolism These are various chemical processes and chemical reactions happening in cells,  Metabolic Pathway It refers to the process of metabolism which starts with a molecule as a starting material then ends up with a product which will be utilized by the cells. Metabolic Pathway 2 Metabolic Pathways  Catabolic Pathway breaking down molecules therefore releasing energy Example: Cellular Respiration  Anabolic Pathways building molecules thus consuming energy Example: Synthesis of cell components such as carbohydrates, proteins and lipids  ATP Adenosine 5’- triphosphate It stores and transport chemical energy in cells. Composition Ribose (Sugar) Adenine (Nitrogenous Base) 3 Phosphate group Works of ATP Enzymes  Enzymes An enzyme is a protein macromolecule and have a specific structure Enzymes in the Body  Enzymes They are crucial as regulators of the various chemical processes happening in the cell.  Roles of Enzymes 1. Lowers Activation Energy 2. Enzymes are Substrate Specific 3. Enzyme Activities are Affected by Certain Conditions  Enzymes Lowers Activation Energy Activation Energy - refers to the amount of energy that is needed to push the reactants to the top of an energy barrier, so the downward reaction will start.  Enzymes Lowers Activation Energy Enzymes help speed up or catalyze reactions by lowering the activation energy or EA. Enzymes are Substrate Specific Substrate refers to the reactants that the enzyme works on. When the binding between substrates and enzymes happen there will be changes in the shape of the enzyme which is called as induced-fit. Enzymes are Substrate Specific Enzymatic reactions start with the substrate attaching to the active site, the binding is mediated by weak interactions such as hydrogen bonds and ionic bonds. Enzyme Activities are Affected by Certain Conditions Effect of Temperature and pH Oxidation-Reduction Reactions  Effect of temperature and pH Enzyme Activities are Affected by Certain Conditions The increasing temperature affects the enzyme activity due to the greater coincidence of substrates colliding with active sites therefore increasing product yield. When temperature condition rises above or below the enzymes preferred temperature or optimal temperature the enzymatic activity will be affected and the enzymatic reaction will drop. High temperature can damage the enzyme’s structure which could alter the shape of the active site, and therefore affect the binding process with the substrates. low temperatures can cause the enzyme to slow down its activity, therefore producing less amount of products. In humans, most enzymes have an optimal temperature of about 35– 40°C (close to human body temperature). While thermophilic bacteria that live in environments with extremely high temperatures contain enzymes with optimal temperatures of 70°C or higher  The acidity or the basicity of the cell environment (pH) can also affect the activity of the enzyme just like the temperature. Pepsin is a digestive enzyme that is usually found in the human stomach and aids the process of digestion, it’s optimal pH is pH2. Trypsin, which is also a digestive enzyme found in the human intestine has an optimal pH of 8, and works best at the alkaline environment, and will be denatured or damaged in the stomach  Cofactors It refers to non-protein molecules that aids the enzyme in catalytic activities.  Enzyme Inhibitors These are certain chemicals that discriminately inhibit the activity of specific enzymes. toxins, poisons, pesticides, and antibiotics. Enzyme Inhibitors  Competitive Inhibitors These inhibitors resemble the structure of normal substrates, then blocks the substrate from binding to the active site.  Non-Competitive Inhibitors Non-competitive inhibitors avoid direct competition with substrates, instead they bind to the other regions of the enzyme, except for the active site.  Non-Competitive Inhibitors Non-competitive inhibitors avoid direct competition with substrates, instead they bind to the other regions of the enzyme, except for the active site.  Allosteric Regulation It refers to any case wherein a protein’s function in another site is affected by the binding of a regulatory molecule in another site.  Allosteric Regulation It refers to any case wherein a protein’s function in another site is affected by the binding of a regulatory molecule in another site.  Allosteric Inhibitor It stabilizes the inactive form of the enzyme  Cooperativity It is another form of allosteric regulation that can intensify enzymatic activity. Oxidation-Reduction Reactions Oxidation-Reduction Reactions These reactions involve electrons transfer from a donor to an acceptor. Oxidation is the loss of electrons. Reduction is the gain of electrons.  Oxidation-Reduction Reactions Catabolism - large molecules are broken down to smaller products, releasing energy and transferring electrons to acceptor molecules of various sorts. (oxidation) Anabolism - small molecules react to give rise to larger ones; this process requires energy and involves acceptance of electrons from a variety of donors. (reduction) Oxidation-Reduction Reactions