Enzymes: The Enzyme Action
Enzymes: The Enzyme Action
Enzymes: The Enzyme Action
Enzymes
Catalyst: a substance that speeds up a chemical reaction and is not changed by the reaction. Enzymes: proteins that function as biological catalysts.
1. The substrate molecule fits onto the active site of the enzyme. 2. The substrate molecule has a specific shape which fits only onto the active site of a specific enzyme in a lock and key model in which the active site is the lock and the substrate is the key. 3. The substrate molecule is brought closer together and broken down / build up (depends on the type of reaction) forming a new product. 4. The enzyme is not changed and is reused.
At a very low or high pH, the enzyme molecules lose their shape so their substrate cannot fit into their active site. For example, pepsin is a proteindigesting enzyme (protease) that works in the stomach at a very low pH pH2 which is why the stomach secretes hydrochloric acid. Amylase works best at pH 7 or slightly above and is found in the mouth.
Germination of Seeds 1. The seed contains the following enzymes: amylase, maltase, lipase, and protease. - Amylase breaks down starch in the seed into maltose. Maltose breaks down maltose into glucose. Glucose is then used in respiration to release energy. - Lipase breaks down lipids into fatty acids and glycerol. Fatty acids are used to build up cell membranes. - Protease breaks down proteins into amino acids which are used for growth. 2. For the enzyme to work, it needs: - Water to activate the enzyme as the enzymes break down substances by hydrolysis to break down large molecules into small molecules). - Oxygen for aerobic respiration to release energy. - Warm temperature to provide the optimum temperature for a high enzyme activity. Biological Washing Powder 1. The hardest stains on clothes to remove are proteins and lipids. 2. The biological washing powders contain the enzyme protease and lipase. 3. Lipase breaks down lipids into fatty acids and glycerol 4. Protease breaks down proteins into amino acids. 5. Its easier to clean when there are enzymes because you cannot remove lipids (fats) and proteins because they are insoluble. Amino acids, fatty acids and glycerol are water-soluble so you can rinse them off easily. Breaking down the substances makes it easier to clean as they become soluble in water. Food industry Pectinase: when juice is squeezed out of apples to make a drink, an enzyme called pectinase is often added. Pectinase is an enzyme that breaks down the substances that hold the cell walls of the apple cells together. This makes it easier to squeeze out more of the juice. It helps to break down the substances that make apple juice look cloudy, turning it into a clear liquid that most people prefer. Lactase: this enzyme breaks down lactose into glucose and galactose. This enzyme is used to digest lactose to make it safe for lactose-intolerant people.
The use of microorganisms and fermenters to manufacture the antibiotic penicillin and enzymes for use in biological washing powders:
In a fermenter, the microorganism grows in a liquid called the medium. The medium must contain everything that the microorganism needs to live and produce the desired product. Penicillium needs: - Oxygen for respiration - A source of carbohydrates, such as sugar or starch for respiration - A source of nitrogen, such as ammonium phosphate to make proteins for growth - A suitable temperature high enough to make sure the reaction happens so the fungus enzyme does not denature. The fermenter is covered with a cooling water-filled jacket around to maintain an optimum constant temperature to prevent the enzymes from denaturing, and from losing its shape because as the fungus respires and releases heat so the temperature in the fermenter increases which would kill the fungus resulting in no penicillin. Acids or alkali are added to maintain the pH and keep it constant as the enzyme needs an optimum pH to give the maximum yield, otherwise the enzyme activity slows down.
The growth of fungus slows down and stops at a point because the nutrients get used up, there are limiting factors, waste products build up and they are toxic, penicillin could inhibit growth and population reaches carrying capacity. To make enzymes for biological washing powders, different bacteria or fungi are used in the medium depending on what enzymes they make.