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Grade 10 Science Related Reading/Chemistry Chemistry Gr10 Name:____________________ Class:____________________ Date:____________________ Chlorinated hydrocarbons Enzymes make the world go and “round” their uses Task 1 – Pre-Reading Activity Watch the animation given in the following link and answer the questions that follow: http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html 1. Enzymes are a. Carbohydrates b. Fats c. Proteins d. Nucleic acids 2. Which one of the following attaches to the enzyme? a. Water b. Substrate c. another enzyme d. product 3. An enzyme can only bind to one reactant at a time. a. True b. False 4. An enzyme speeds up a chemical reaction in a cell , but can be used only once. a. True b. False Page 1 of 7 Task 2 – Reading Activity Enzymes are compounds that assist chemical reactions by increasing the rate at which they occur. For example, the food that you eat is broken down by digestive enzymes into tiny pieces that are small enough to travel through your blood stream and enter cells. Enzymes are proteins that are found in all living organisms. Without enzymes, most chemicals reactions within cells would occur so slowly that cells would not be able to work properly. Enzymes function as catalysts. Catalysts accelerate the rate of a chemical reaction without being destroyed or changed. They can be reused for the same chemical reaction over and over, just like a key can be reused to open a door many times. Enzymes are generally named after the substrate affected, and their names usually end in -ase. For example, enzymes that break down proteins are called proteases. While lipases break down lipids, carbohydrases break down carbohydrates. The compounds that enzymes act upon are known as substrates. The site at which the enzyme attaches to substrate is called the active site. An enzyme can lower the energy needed for a reaction to occur, thus making this reaction faster. The energy required for a chemical reaction to occur is known as the activation energy. Once the reaction between an enzyme and a substrate is complete, the substrate is changed to a product while the enzyme remains unchanged. Since the 1950s, enzyme technology has really taken off. It is the basis of the new industry called biotechnology. There are great benefits in using enzymes as catalysts to make products. They can be some 10,000 times more efficient than ordinary inorganic catalysts used in industry. One enzyme molecule can catalyse 10 million reactions in a single second! They also work at relatively low temperatures (typically, about 40 °C), saving energy and therefore saving money. Some of the Industrial applications of enzymes are as follows: Yoghurt Milk contains a sugar called lactose. Natural bacteria in the milk turn this into lactic acid . It is the first step in making cheese or yoghurt. Nowadays cheese and yoghurt makers use pasteurized milk. This has been heated to kill any bacteria. So they add their own bacteria to start off the process. Enzymes in bacteria break down lactose into two simple sugars . Then other enzymes convert the sugars into lactic acid. Page 2 of 7 Confectionery break down starch syrup into glucose syrup (carbohydrases are used); change glucose into fructose, which is sweeter so less is needed and is used in 'slimming' foods (isomerase); Biological detergents break down stains (proteases attacks proteins and lipases attack fats); soften fabrics (cellulases break down the 'bobbly' bits that can form) Meat make the meat tender Medical treat cancer, make drugs such as synthetic penicillin , help in digestion. Key Vocabulary enzyme substrate catalyst product Active site Activation energy Biotechnology lipases cellulases proteases isomerase carbohydrases Page 3 of 7 A. Match the following terms with their definitions by writing the correct letter in the middle column: Term product active site enzyme substrate catalyst activation energy Definition a. Amount of energy required for a chemical reaction to occur. b. Substances that bring about a chemical reaction without being changed itself. c. Substances on which an enzyme acts. d. Regions on the surface of enzymes that fit the substrate. e. Substance formed from the substrate at the end of a chemical reaction with an enzyme. f. Proteins that speed up chemical reactions. B. The illustration below shows how an enzyme works. Use the terms provided in the box to place them in the correct place. Page 4 of 7 C. Answer the following Questions: 1. Name 3 characteristics of enzymes. ____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ 2. How do names of enzymes end? Give examples. ____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ 3. What are enzymes named after. Give examples. Page 5 of 7 ____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ 4. Enzymes have an optimum temperature at which they work best. Temperatures above and below this optimum will decrease enzyme activity. Which graph best illustrates the effect of temperature on enzyme activity? ____________________________________________________________________________ ____________________________________________________________________________ ____________________________________________________________________________ D. (1)From the given illustration identify the following: Substrate : ________________________________ Enzyme : _________________________________ Product : _________________________________ Page 6 of 7 (2) Given below is an enzyme and 4 different molecules . Which molecule would most likely react with the enzyme? ____________________ Explain your answer : ____________________________________________________________________________ ____________________________________________________________________________ Task 3 – Post Reading Activity Complete the graphic organizer to show the various ways in which enzymes catalyze Industrial processes Biotechnology What are the benefits of using enzymes as catalysts? Page 7 of 7 ______________________________________________ ______________________________________________ ______________________________________________