CH 5 Enzymes 2024 Extended PDF

BY CELL :00201110983031 00201110983031 [email protected]  1. Define the term catalyst as a substance that increases the rate of a chemical reaction and is not changed by the reaction 2. Define enzymes as proteins that function as biological...

BY CELL :00201110983031 00201110983031 [email protected]  1. Define the term catalyst as a substance that increases the rate of a chemical reaction and is not changed by the reaction 2. Define enzymes as proteins that function as biological catalysts 3. Describe why enzymes are important in all living organisms in terms of reaction speed necessary to sustain life 4. Describe enzyme action with reference to the complementary shape of an enzyme and its substrate and the formation of a product 5. Investigate and describe the effect of changes in temperature and pH on enzyme activity 6. Explain enzyme action with reference to the active site, enzyme-substrate complex, substrate and product 7. Explain the specificity of enzymes in terms of the complementary shape and fit of the active site with the substrate 8. Explain the effect of changes in temperature enzyme activity in terms of kinetic energy, shape and fit, frequency of effective collisions an denaturation 9. Explain the effect of changes in pH on enzyme activity in terms of shape and fit and denaturation CELL :00201110983031 00201110983031 [email protected] Biological Catalyst: as a substance that increases the rate of a chemical reaction and is not changed by the reaction or change the product. ENZYMES proteins that are involved in all metabolic reactions, where they function as biological catalysts. How the enzyme does work Substrate is the substance on which an enzyme acts. Each enzyme has a certain substrate on which it acts. Examples: 1. The enzyme pepsin which is secreted by the walls of the stomach its substrate is protein Protein Pepsin Polypeptides CELL :00201110983031 00201110983031 [email protected]  The Main Characteristics of Enzymes - Enzymes are specific in their function 1. Means that each enzyme speeds up a certain reaction only 2. Are affected by temperature 3. Are affected by PH 4. Concentration of the enzyme. 5. Concentration of the substrate. The enzyme activity 1. is affected by temperature The activity of most enzymes increases by the increase in temperature till about 35°C TO : 40°C , then any increase in temperature leads to a decrease in the activity of the enzyme. EXPLAIN WHY THE RATE OF ENZYME ACTIVITY INCREASES AS THE TEMPERATURE INCREASES. - Increase in temperature increases rate of reaction as it increases kinetic energy of molecules of both enzyme and its substrate then increase the collision rate between enzyme and substrate making them move around faster making it easier for them to react. - Above 50°C the enzymes denature (means that it loses its activity and cannot regain it even if the temperature changes) CELL :00201110983031 00201110983031 [email protected]  DEFINE OPTIMUM TEMPERATURE OF AN ENZYME it is the temperature at which the enzyme works best. 2.Are affected by pH value DEFINE OPTIMUM PH - It is the pH value at which an enzyme works best - Any increase or decrease around this pH decreases the activity of the enzyme - Extremes of pH changes may denature some enzymes CELL :00201110983031 00201110983031 [email protected]  How do enzymes act - Each enzyme has a region in it called the active site where its substrate fits exactly, and this allows the enzyme to act on a certain substrate Role of enzymes in the germination of seeds 1. Seeds contain stored insoluble food with inactive enzymes 2.when water enters the seed and in suitable conditions the enzymes in the seed become active catalyse the gradual breakdown of stored insoluble food in the seed to a soluble form 3. this form can be uses by the embryo till it forms green leaves which are used in making food by photosynthesis. Examples of such enzymes IMPORTANT ENZYMES FOR GERMINATION: 1. Amylase which catalyses the breakdown of stored insoluble starch to a soluble sugar known as maltose 2. Proteases which catalyse the breakdown of stored insoluble proteins into soluble amino acids. Role of enzymes in biological washing powder removing stains by breaking the insoluble molecules of stains into soluble molecules so they can be washed and removed by water. CELL :00201110983031 00201110983031 [email protected]  IMPORTANT ENZYMES FOR WASHING POWDER 1. Lipases - Enzymes which catalyze the breakdown of fats to fatty acids and glycerol and this is important in removing greasy stains 2. Proteases - Enzymes which catalyse the breakdown of insoluble proteins into soluble amino acids and this is important in removing protein stains such as blood stains Advantages of Biological Washing Powder - Save expense of boiling - Avoid the damage of clothes by boiling and rubbing TRICKS 1. Enzymes cannot be used for silk, wool or leather, which contain proteins, as it may be damaged by the proteases in the biological washing powder 2. Hands should be washed after using these powders in order not to be harmed by the enzymes in biological washing powders ROLE OF ENZYMES IN FOOD INDUSTRY Pectinase enzyme used in juice making Pectin is a substance found in plant cell walls, when pectinase enzyme is used it acts on the plant cell wall. CELL :00201110983031 00201110983031 [email protected] IMPORTANCE OF PECTIN: SIC 1. Makes it much easier to squeeze juice from fruit 2. Helps in increasing the volume of the juice produced 3. Makes juice clear rather than cloudy ROLE OF ENZYMES IN MAKING BABY FOOD# 1. Protease enzymes used in making baby foods Act on proteins in food to be broken down into small polypeptides or amino acids to be easily absorbed by their digestive system. 2. Amylase used in obtaining sugar from starch act on starch for making maltose which is used in sweet making. Isomerase enzyme is used in converting glucose into fructose, As fructose is sweeter so less sugar can used by diabetic As they can use a smaller amount of the glucose for sweeting the drinks and food. 3. Lactase enzyme is used to break down lactose of milk Lactase acts on lactose of milk to be digested into glucose and galactose to help those have problems in digesting lactose of milk. CELL :00201110983031 00201110983031 [email protected] 4. rennin this enzyme clots milk at the first stage of making cheese. Advantages of using enzymes in Industry SCC 1. Enzymes work at low temperatures, so saving energy 2. Enzymes are not corrosive 3. Enzymes are specific, so the process can be controlled CELL :00201110983031 00201110983031 [email protected]