WITHOUT ANSWERS
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1. The sum of all chemical reactions occurring inside a living cell is called ______. A. metabolism B. synthesis C. dehydration synthesis D. hydrolysis E. thermodynamics 2. True or False. Every reaction in a cell requires a specific coenzyme. 3. True or False. A cell must produce large quantities of each enzyme in order to survive. 4. A(An) ______ begins with a particular reactant, terminates with an end product, and has many minute steps in between. A. thermodynamic law B. metabolic pathway C. synthetic reaction D. hydrolytic reaction E. energy of activation 5. True or False. An increase in temperature will cause molecules to move faster, thereby having a decreased chance of collision. 6. True or False. An enzymatic reaction can bring about only synthesis, i.e., two smaller molecules joined to form a larger molecule. 7. True or False. All enzymes are proteins. 8. True or False. The reactants in an enzymatic reaction are called the substrates for that enzyme. 9. Which of the following statements is NOT correct for a metabolic pathway? A. One reaction leads to the next reaction. B. They begin with a particular reactant and terminate with an end product. C. One pathway may lead to other pathways if there are several molecules in common. D. Metabolic energy is captured more easily if it is released in large amounts rather than in small increments. E. Metabolic pathways are highly organized and structured. 10. Study this metabolic pathway: A -E1 -> B -E2 -> C -E3 -> D. Which of the following statements is NOT correct? A. A is the substrate for enzyme E1 and B is the product. B. A is the product for enzyme E1 and B is the substrate. C. Enzyme E2 can catalyze the substrate B but not substrates A, C, and D. D. B is the product formed by enzyme E1 but the substrate for enzyme EB. E. A is a reactant in the first reaction that forms the product B. 11. Which of the following statements is NOT correct about enzymes? A. Most enzymes are protein molecules. B. Every reaction in a cell requires a specific enzyme. C. Enzymes speed up a chemical reaction. D. Enzymes are named for the products formed. E. Enzymes are absolutely necessary to the continued existence of a cell. 12. Which of the following is NOT an enzyme? A. lipase B. urease C. maltose D. ribonuclease E. dehydrogenase 13. Which of the following enzymes will remove hydrogen atoms from its substrate? A. lipase B. urease C. maltose D. ribonuclease E. dehydrogenase 14. Lactase is an enzyme that breaks down ______. A. lipids B. lactose C. maltose D. sucrose E. urea 15. Each enzyme can speed up only one particular reaction. This specificity is due to the ______. A. specific shapes of both the enzyme and the substrate B. lowering of the energy of activation C. pH of the surrounding medium D. temperature of the surrounding medium E. permanent binding of the enzyme-substrate complex 16. The amount of energy (e.g., heat) needed for a reaction to occur is called the ______. A. kinetic energy B. potential energy C. synthetic energy D. energy of deactivation E. energy of activation 17. Which of the following statements is NOT correct about enzymes? A. Enzymes allow reactions to occur at moderate temperature. B. Enzymes bind with their substrates in such a way that the reaction can occur more readily. C. Enzymes raise the energy of activation for a reaction. D. Enzymes bring together particular molecules and cause them to react with one another. E. Enzymes can be used over and over again. 18. The ______ is a place where the substrates fit onto the enzyme in such a way that they are oriented to react. A. active site B. inhibitory site 3 enzyme-substrate complex D. metabolic pathway E. coenzyme 19. Which of the following statements about enzymes is NOT correct? A. Enzymes speed up a chemical reaction. B. The active site on the enzyme may undergo a slight change in shape when the substrate binds. C. Enzymes are very specific in their action. D. The presence of an enzyme will change the outcome of a reaction. E. Enzymes lower the energy of activation for a reaction to occur. 20. Which of the following statements about enzymes is NOT correct? A. Substrates fit onto the enzyme at the active site. B. No permanent change in the enzyme occurs when it combines with the substrate. C. Once the enzyme has combined with the substrate, the enzyme cannot be used again. D. Enzymes decrease the amount of heat needed by a cell for a chemical reaction to occur. E. Enzymes are named often for their substrates. 21. When the substrate binds to the enzyme, the active site undergoes a slight alteration to achieve the best fit. This is known as the ______ model. A. lock-and-key B. induced-fit C. deduced-fit D. reduced-fit E. fit-to-be-tied 22. Which of the following statements is NOT correct? A. Catalase converts hydrogen peroxide into water and oxygen. B. Generally, enzyme activity increases as substrate concentration increases. C. Generally, enzyme activity decreases as substrate concentration decreases. D. The enzyme's rate of activity can increase even after all the active sites have been filled. E. A denatured enzyme cannot form an enzyme-substrate complex. 23. Which of the following statements is NOT correct about enzymes? A. A rise in temperature generally results in a decrease in enzyme activity. B. A temperature above a certain point will cause the enzyme to denature. C. High temperatures disrupt the hydrogen bonding between amino acids. D. High temperature affects the secondary structure of the protein enzyme. E. Each enzyme has an optimal pH and temperature. 24. True or False. Enzymes can only be denatured by high temperatures. 25. High temperatures disrupt the hydrogen bonding between ______ of a protein and cause the enzyme to become denatured. A. amino acids B. fatty acids C. nucleic acids D. monosaccharides E. nucleotides 26. True or False. A denatured protein has lost its normal shape and therefore its ability to form an enzyme-substrate complex. 27. Pepsin, an enzyme found in the stomach, acts best at a pH of about two but it is not active at a pH of 7. Why? A. The optimal pH helps to maintain the enzyme's tertiary structure. B. The optimal pH helps to maintain the enzyme's primary structure. C. The optimal pH disrupts the normal interactions of the R groups within the protein molecule. D. The pH of two causes denaturation to occur but not at pH of 7. 28. Within limits, the rate of enzymatic reaction doubles with every ______ C rise in temperature. A. 5° B. 10° C. 20° D. 30° E. 40° 29. In an enzymatic reaction, more product can be obtained if there is ______. A. enough substrate to fill all the active sites B. optimum pH C. optimum temperature D. enough substrate to fill all the active sites and there are optimal pH and optimal temperature conditions. 30. A(An) ______ is any molecule that binds with an enzyme other than its substrate. A. reactant B. product C. inhibitor D. coenzyme 31. ______ inhibition is the normal way by which metabolic pathways are regulated in cells. A. Competitive reversible B. Competitive irreversible C. Noncompetitive reversible D. Noncompetitive irreversible 32. In ______ inhibition, another molecule is so close in shape to an enzyme's substrate that this molecule can compete with the true substrate for the active site of the enzyme. A. competitive B. noncompetitive C. reversible D. irreversible 33. If an inhibitor binds to an enzyme at a site other than the active site, it is called ______ inhibition. A. competitive B. noncompetitive C. reversible D. irreversible 34. Hydrogen cyanide is an inhibitor of the enzyme cytochrome oxidase, which is used to make ATP in mitochondria. Cyanide acts as a(an)_______. A. cofactor B. enzyme inhibitor C. denaturing agent D. substrate complex 35. Penicillin causes the death of bacteria due to ______. A. competitive inhibition B. noncompetitive inhibition C. denaturing the bacteria D. substituting a cofactor 36. A(An) ______ is generally a large molecule that the body is incapable of synthesizing without the ingestion of a vitamin. A. ion B. cofactor C. coenzyme D. enzyme E. inhibitor 37. ______ are organic molecules that bind to enzymes and serve as carriers for chemical groups or electrons. A. Ions B. Cofactors C. Coenzymes D. Enzymes E. Vitamins 38. Which of the following is considered to be a coenzyme? A. magnesium ion B. riboflavin C. biotin D. niacin E. NAD+ 39. Which of the following is considered a vitamin? A. NAD B. NAD+ C. NADP D. potassium ion E. niacin 40. ______ are organic dietary requirements needed in small amounts only. A. Cofactors B. Coenzymes C. Vitamins D. Minerals E. Enzymes