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=ENZYME QUESTIONS 2.1=

1. Respiration and mitosis 2. Enzymes are reffered to as biological catalysts because they speed up chemical reactions within a living organism. Such as amylase speeding up the break down of starch into glucose. 3. a) Enzymes are proteins that act as biological catalysts to control the metabolism of the cell. They play critical roles in metabolic pathways in living organisms. b) Protein c) Enzymes relate to their substrates in that the active site of an enzyme has an affinity to the substrate, and they fit together in either the 'lock and key' model or the 'induced fit' model and the enzyme breaks the substrate into products. d) Enzymes are involved in metabolic pathways in a way that they break down molecules such as Starch, into smaller molecules such as glucose, which can then be used as energy to increase metabolism. //(Matho im making this all up off the top of my head. i have no idea where we are spose to find the answers?) **You are spot on. You can read through the enzyme stuff in your textbook but there wont be a sentence in it giving you the answer.**// 4.'Specificity' of an enzyme means that it is specific to a certain substrate __and to an optimum temperature and pH. **Just stick to your first point.**__ 5. //Matho... wheres figure 2.2? **Don't worry about this question HM**// 6. Enzymes can be used over and over again because they do no get used up in a reaction. 7. a) Activation energy reffers to the amount of energy required to kick start a reaction. b) Enzymes reduce the activation energy of a reaction, enabling the reaction to start quicker because it requires less energy. 8. a) Enzyme affinity is the attraction of an enzyme to its substrate **(//or to an inhibitor HM)//** b) An Enzymes affinity can be altered by denaturing. which changes the shape of the enzyme stoping it was being able to fit any substrate. c) as above 9. Both Temperature and pH influence on the rate of enzyme-controlled reactions in a way that, if too high above the optimum, the active site of an enzyme will change shape (permanently if the temperature is too high (denaturing)) and it is no longer able to fit a substrate. If the temperature is too low, the enzymes active site again changes shape, but not permanently. 10.Temperature - may change the shape of an enzyme (sometimes permanently), reducing the metabolic reactions pH - may change the shape of the enzyme, reducing the metobolic reactions. Substrate concentration - if more substrate is added to an enzyme solution it will initially speed up the reaction, but eventually there will be too many substrates for the enzymes to work on and it wont go any faster. the enzyme acts as the limiting factor. Enzyme concentration - if more enzymes are added to a substrate solution it will initially speed up the reaction, but eventually there will be too many enzymes and not enough substrates for the enzymes to work on so the reaction wont go any faster. the substrates act as the limiting factor. Inhibitors - inhibitors join on to an enzymes active site and stops the enzymes being able to break down substrates. this results in a slower reaction as the inhibited enzymes are unable to participate in the reaction. 11. A cofactor is a non-protein part that is required of some enzymes before they act. Cofactors include metallic ions such as iron, calcium, copper and zinc. A coenzyme is a cofactor which is made of an organic molecule rather than a metallic ion. Coenzymes include vitamins. Some enzymes are unable to act on a substarte without teh presence of one of these cofactors. 12.Two examples of enzymes being used in commercial use are: -washing powders - ?? 13. An enzyme definciency, such as a deficiency of lactase, resolts in a disease called lactose intolerance. Lactose is a suger in milk, and when a person is lactose intolerant, their body doenst contain the enzyme Lactase which is needed for the break down of this sugar into glucose. Without being able to digest this sugar, the lactose sits in a persons intestines and is unable to cross through into the blood stream. This results in a person suffering from abdominal pains, cramps, flatulence and diahorea. to avoid these unpleasant symptoms, someone with lactose intolerance has to avoid consuming dairy products. 14. a) an anabolic reaction is a reaction requiring energy to construct molecules from smaller units. b) an example of an anabolic reaction is the building of proteins from amino acids, which is done in the cell by the endoplasmic reticulum(?) 15. a) a catabolic reaction is a reaction that breaks down molecules into smaller units and releases energy. b) an example of a catabolic reaction is the breakdown of muscle protein in order to use amino acids as substrates, and which releases energy. 16. The four main groups of polymers that make up living organisms are: -Proteins -Lipids -Carbohydrates -Nucleic Acids 17.a) the difference between dehydration and hydrolysis is that dehydration is when water is used to joined to monomers together, where as hydrolysis is when water is used to 'cut' a polymer into monomers. b) hydrolysis is a catabolic reaction and dehydration is an anabolic reaction. c) i) dehydration ii) hydrolysis