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BIOLOGICAL MOLECULES.pdf
- 1. STATEMENT OF INQUIRY Thesystems of life are supported by biochemical reactions and the transformation of energy that occur within cells. Innovation in science could lead to these reactions being utilized to meet growing energy and food needs KEY CONCEPT Systems RELATED CONCEPT Transformation and Energy GLOBAL CONTEXT Scientific and Technological Innovation What chemical processes support life?
- 2. WHY ARE ENZYMESNEEDED?
- 3. What’s the missinglink? What is the link between digestion, photosynthesis, bread, wine and washing powder? They all depend on enzymes.
- 4. The part ofan enzyme where the reaction occurs is known as the active site Active site: Enzyme What are Enzymes? Enzymes are proteins that function as biological catalysts Catalyst is a substance that increases the rate of a chemical reaction and is not changed by the reaction
- 5. The molecule theenzyme acts on is known as the substrate or reactant Active site: The site on the enzyme where the reaction occurs Enzyme Substrate molecules Enzymes
- 6. The molecule theenzyme produces is known as the product molecule Active site: The site on the enzyme where the reaction occurs Enzyme Product molecules Enzymes
- 7. Naming Enzymes • Mostenzymes have an –ase ending • The root name suggests what molecule it acts upon or • Example – carbohydrase breaks down carbohydrate – proteases break down proteins – lipases break down lipids
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- 9. What are enzymesmade of? Enzymes are protein molecules, and so are made up of amino acids. Most enzymes contain between 100 and 1,000 amino acids. These amino acids are joined together in a long chain, which is folded to produce a unique 3D structure.
- 10. Why is shapeimportant? The shape of an enzyme is very important because it has a direct effect on how it catalyzes a reaction. An enzyme’s shape is determined by the sequence of amino acids in its structure, and the bonds which form between the atoms of those molecules. Why do enzymes have different shapes? Different types of enzymes have different shapes and functions because the order and type of amino acids in their structure is different.
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- 12. LOCK AND KEYMODEL In the same way that a key fits into a lock, so a substrate is thought to fit into an enzyme’s active site. The enzyme is the lock, and the substrate is the key. enzyme reactant + enzyme- substrate complex ↔ products enzyme + ↔ + ↔ ↔ +
- 13. The lock andkey model
- 14. Plenary substrate enzyme products active site Label enzyme,active site, enzyme, product, enzyme-substrate complex Enzyme-substrate complex
- 15. Enzyme-Substrate Interaction The activesite of the enzyme and substrate molecules have complementary shapes so they fit together By bringing the substances close together, the enzyme molecule makes the reaction take place much more rapidly The enzyme cause a strain in the bond between the substrates, making it easier for it to break
- 16. Enzymes may breakor form chemical bonds between molecules
- 17. Factors affecting enzymeaction The rate of enzyme–catalyzed reactions depends on several factors. What are some of these? All enzymes work best at only one particular temperature and pH: this is called the optimum. Factors that affect the rate of a reaction include: substrate concentration temperature Different enzymes have different optimum temperatures and pH values. pH Surface area
- 18. Factors affecting enzymes Ifthe temperature and pH changes sufficiently beyond an enzyme’s optimum, the shape of the enzyme irreversibly changes. normal denatured heat pH When this happens the enzyme is denatured.
- 19. Rate Of Reaction Temperature/o C 0 10 2030 40 50 60 70 Optimum temperature Enzyme is denaturing Rate of reaction of an enzyme reaction changes at different temperatures Molecules gain kinetic energy causing more collisions between enzymes an substrate Enzymes and temperature
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- 21. Enzymes prefer towork at an optimum pH. Outside of its pH range the enzyme is denatured. Rate Of Reaction pH 1 2 3 4 5 6 7 8 9 10 11 12 pepsin amylase The activity and shape of enzymes is also affected by pH Optimum pH Enzymes and temperature
- 22. The Effect ofSubstrate Concentration on Enzyme Activity
- 23. Temperature, pH andsubstrate concentration can all affect the rate of activity of enzymes. Above are sketch graphs graphs showing how each factor affects enzyme activity. Factors affecting the rate of enzyme activity
- 24. Enzymes and cells Enzymescatalyze the thousands of reactions that need to take place in order to maintain life. What are some of these reactions? digestion respiration photosynthesis (plants and some bacteria) protein synthesis.
- 25. Enzymes are importantin seed germination starch embryo plant amylase secreted maltose absorbed Enzymes and cells
- 26. Enzymes are usedin the food industry • Pectinase break down substances in apple cell walls and enable greater juice extraction. • Pectinase changes fruit juices from cloudy to clear
- 27. Enzymes are usedin the food industry Lactase breaks down lactose in milk into glucose and galactose. This makes milk drinkable for lactose intolerant people.
- 28. Enzymes are usedin biological washing powders • Why are enzymes needed in washing powders?
- 29. How do enzymeshelp to clean clothes? The enzymes are coated with a special wax that melts in the wash, releasing the enzymes. Once the stains have been broken down, they are easier for the detergent to remove. Biological washing powders and liquids contain enzymes that help remove stains. Proteases break down proteins in stains such as grass, blood and sweat. Lipases break down stains containing fat and oil. Carbohydrases break down carbohydrate-based stains, such as starch.
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- 32. PRACTICAL WORK WITHENZYMES • Effect on temperature on the activity of catalase • In this experiment, the enzyme to be extracted and tested is catalase and the substrate is hydrogen peroxide (H2O2). • Certain reactions in the cell produce hydrogen peroxide, which is poisonous. • Catalase makes the hydrogen peroxide harmless by breaking it down to water and oxygen. • How much oxygen is produced can be measured and that gives a measure of the activity of the enzyme • The rate of production of oxygen is measured at different times
- 33. Example: Effect ontemperature on the activity of catalase • Independent variable (manipulated variable) – Temperature • Dependent variable – Rate of oxygen production • Controlled variables (keep the same) – Variety of potato – The number of potato discs – Concentration of hydrogen peroxide – pH
- 34. Catalase Experiment-Enzymes andtemperature
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- 36. Effect of pHon the activity of catalase