Biology 1: Chapter 5: Energy, Metabolism, and Enzymes

b. environment.

1.The energy required for life processes must be extracted from an organism's a. nucleus. c. predators. b. environment. d. biosynthesis.

c. Carbon and other atoms tied up in wooden structures are not being recycled into other living organisms.

10. When humans cut down trees for lumber to build permanent structures, what aspect of metabolic cycling is disrupted? a. The oxidation of wood products reduces the amount of photosynthesis that can occur. b. The biosynthetic reactions that occur in the lumber cause too much catabolism to occur. c. Carbon and other atoms tied up in wooden structures are not being recycled into other living organisms. d. The DNA in the wood is unable to obey the first law of thermodynamics.

c. The breaking of the chemical bonds of a storage molecule transfers energy, no matter what molecule is stored.

11. Plants and animals use different energy storage molecules, yet they both use the same mechanism to "burn" their stored energy. How can plants and animals both be successful, even though they "burn" different energy storage molecules? a. The internal components of plant and animal cells are identical. b. The second law of thermodynamics says that all cells have the same energy transfer system. c. The breaking of the chemical bonds of a storage molecule transfers energy, no matter what molecule is stored. d. All organisms have the same enzymes to catalyze their energy-producing reactions.

d. random movement or vibration of the molecules of any substance (water molecules in a beaker, for example).

12. The term thermal energy describes the a. orderly movement of electrons along a conductor (such as a wire). b. movement of photons as they travel through space. c. attractive power of two magnets toward one another. d. random movement or vibration of the molecules of any substance (water molecules in a beaker, for example).

c. first; the total amount of energy in a defined system remains constant

13. It is possible to predict the amount of energy released during a chemical reaction (as shown in the illustration below) because the _____ law of thermodynamics states that _____. a. first; energy and matter are equivalent b. second; any use of energy affects the entire universe c. first; the total amount of energy in a defined system remains constant d. second; energetic systems become less organized over time

d. amount of work performed plus heat from friction, plus heat from the exhaust, plus the potential energy of combustion products in the exhaust.

14. In accordance with the first law of thermodynamics, the energy in a gallon of gas consumed in a mileage test is equal to the a. amount of work performed, a calculation based on miles traveled and the weight of the vehicle. b. amount of work performed plus the heat created from the friction of moving parts. c. amount of work performed plus the heat from friction, plus the heat of the exhaust from the motor. d. amount of work performed plus heat from friction, plus heat from the exhaust, plus the potential energy of combustion products in the exhaust.

b. The conversion of metabolic energy into muscle contraction is not 100 percent efficient and some of the energy is lost as heat.

15. Why is heat shown flowing from the worker in the illustration below? b. The conversion of metabolic energy into muscle contraction is not 100 percent efficient and some of the energy is lost as heat. c. Using a hammer, paintbrush, or any other tool generates friction and heat in the arm that must be lost to maintain homeostasis. d. Energy and matter are equivalent; the conversion of the worker's body mass to kinetic energy requires a reduction of body mass and is indicated by the outflow arrows.

b. The decomposition of a fallen tree trunk on the forest floor.

16. Consider the change in the status of the polymer in the living cell and the dead cell. What real-life process does the illustration below represent? a. The conversion of living tissue to rock during fossilization. b. The decomposition of a fallen tree trunk on the forest floor. c. The conversion of the wax in a burning candle to carbon dioxide and water. d. all of the above

b. be unaffected because no changes in the bonding pattern of the molecule had taken place.

17. All molecules have a combination of kinetic and potential energy. If an external heat source were used to increase the kinetic energy of a group of molecules, the potential energy of the group would a. decline because the sum of kinetic and potential energy always equals 100 percent. b. be unaffected because no changes in the bonding pattern of the molecule had taken place. c. also increase because potential and kinetic energy are directly proportional to one another. d. It is not possible to predict the result using the information provided.

d. Heat is a natural by-product of most chemical reactions.

18. Organisms that maintain a constant body temperature rely on the heat produced by cells. Where does this heat come from? a. Special metabolic pathways exist just for the production of heat. b. Mitochondria produce heat in the form of ATP. c. Plants store up heat as they perform photosynthesis. When an organism digests a plant, that heat is released. d. Heat is a natural by-product of most chemical reactions.

b. Anabolic

19. _____ reactions use energy to build complex molecules. a. Catabolic c. Photosynthetic b. Anabolic d. Redox

a. potential energy.

2. A spherical rock rests at the top of a steep hill. The rock has a. potential energy. c. kinetic energy. b. chemical energy. d. no energy.

b. products.

20. In the reaction C6H12O6 + 6 O2 6 CO2 + 6 H2O, the 6 CO2 molecules are some of the a. substrates. c. enzymes. b. products. d. reactants.

b. this reaction requires an input of energy to convert glucose and O2 to H2O and CO2.

21. The graph below depicts the amount of energy involved over the course of a chemical reaction. The graph indicates that a. the products of this reaction have more energy than the substrates. b. this reaction requires an input of energy to convert glucose and O2 to H2O and CO2. c. this reaction can only run in one direction (from left to right on the graph). d. this reaction occurs only in the presence of an enzyme.

b. catabolic reactions

22. A decrease in potential energy between reactants and products is typical for what type of chemical reaction? a. anabolic reactions b. catabolic reactions c. the formation of peptide bonds d. those occurring without the aid of an enzyme

c. more stable and have less energy

23. A molecule of sugar slowly "burns" in one of your cells. The products of these catabolic reactions are _____ than the original sugar molecules. a. less stable and have more energy c. more stable and have less energy b. more stable and have more energy d. less stable and have less energy

d. capture as much of the released energy as possible.

24. The metabolism of living organisms consists of a series of catabolic and anabolic reactions; the latter are very carefully controlled, allowing the organism to a. minimize the release of carbon dioxide into the atmosphere. b. assess its metabolic state and respond appropriately. c. avoid consuming its food resources too quickly. d. capture as much of the released energy as possible.

d. ATP

25. Which of the following is either consumed or synthesized in virtually every cellular reaction? a. sugars c. DNA b. enzymes d. ATP

b. energy is released and can power cellular activities.

26. When ATP breaks down into ADP and a phosphate group, a. energy is absorbed by ADP and transferred to enzymes. b. energy is released and can power cellular activities. c. ADP becomes the active site in an enzyme. d. the energy in the broken bond is transferred to the phosphate group.

c. CH4

27. Which of the following compounds is the least oxidized? a. C6H11O6 c. CH4 b. CO2 d. HCOOH

b. carbon is oxidized and oxygen is reduced.

28. In the reaction CH2O + O2 CO2 + H2O, a. carbon is reduced and hydrogen is oxidized. b. carbon is oxidized and oxygen is reduced. c. carbon and hydrogen are reduced. d. carbon and oxygen are oxidized.

d. causing reactants to collide more often.

29. Heat speeds up chemical reactions by a. causing the cell to produce enzymes that lower the activation energy of the reactions. b. decreasing the amount of oxygen available for redox reactions. c. inhibiting catabolic reactions while promoting anabolic reactions. d. causing reactants to collide more often.

b. as kinetic energy when the spring arm was pulled back and latched.

3. Imagine a system consisting of a mousetrap with the arm set and latched and with the level of potential energy high. This potential energy was added to the mousetrap a. when it was first constructed. b. as kinetic energy when the spring arm was pulled back and latched. c. when the latch was released and the arm sprang forward. d. when the various materials used to construct the mousetrap were selected.

b. nearly all chemical reactions are catalyzed by enzymes.

30. In a human cell, a. one enzyme usually catalyzes no more than five different chemical reactions. b. nearly all chemical reactions are catalyzed by enzymes. c. enzymes have to be constantly replaced as they are used up in the reactions that they catalyze. d. some enzymes are specialized to store activation energy.

a. proteins.

31. Enzymes are a special class of a. proteins. c. chemical bonds. b. nucleotides. d. hormones.

d. They decrease the amount of activation energy required.

32. What do catalysts and enzymes have in common? a. They decrease the number of collisions between substrate molecules. b. They increase the amount of activation energy required. c. They increase the amount of substrate that is available. d. They decrease the amount of activation energy required.

c. The platinum is a catalyst.

33. Imagine a chemical reaction during which a solution turns from red to green very slowly. If a small piece of platinum is placed in the solution, the change occurs much more rapidly, yet the platinum remains unchanged. Which of the following best explains this experimental result? a. The platinum provided activation energy. b. The platinum is an enzyme. c. The platinum is a catalyst. d. The platinum is an oxidizing agent.

d. lowers the activation energy of a particular reaction.

34. A given enzyme a. can be used for many different kinds of chemical reactions. b. is permanently changed during a chemical reaction. c. has a special site where the products bind before the reaction begins. d. lowers the activation energy of a particular reaction.

c. enzyme.

35. In the reaction H2O + CO2 + carbonic anhydrase H+ + HCO3-+ carbonic anhydrase, carbonic anhydrase is a(n) a. reactant. c. enzyme. b. product. d. active site.

d. The heat speeds molecular movement, increasing the likelihood of collisions between an enzyme and its substrate.

36. The heat given off by living systems can increase the likelihood that a given chemical reaction takes place. Why is this true? a. The enzymes that catalyze reactions in living systems work increasingly better as the temperature decreases. b. The heat given off lowers the internal cellular temperature, which allows reactions to proceed more quickly. c. The heat allows photosynthesis to occur more rapidly. d. The heat speeds molecular movement, increasing the likelihood of collisions between an enzyme and its substrate.

a. chance encounter.

37. An enzyme and its substrate find each other by a. chance encounter. c. catalysis. b. magnetic attraction. ' d. oxidative reactions.

d. they encounter a substrate that fits their active site.

38. Enzymes can catalyze a reaction only if a. they encounter a molecule of ATP. b. their active site is sufficiently oxidized. c. they have both products in their active site at the same time. d. they encounter a substrate that fits their active site.

c. enzymes and ATP.

39. Biosynthetic reactions require many things, including a. carbon dioxide and water. c. enzymes and ATP. b. glucose and water. d. sunlight and CTP.

d. systems tend to become more disorderly.

4. The second law of thermodynamics states that a. metabolic reactions must be balanced. b. the flow of energy connects living things to their environments. c. energy can be created but not destroyed. d. systems tend to become more disorderly.

a. catalyze a catabolic reaction.

40. Some kinds of drain cleaners use enzymes rather than strong, more dangerous chemicals. These enzymes must be able to a. catalyze a catabolic reaction. b. raise the activation energy of the reaction that clears the clog. c. create energy that can be used to break up the clog. d. allow excess heat to be passed off into the environment.

a. When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around the substrates.

41. The image below diagrams the action of an enzyme. Notice that the enzyme is depicted as being more tightly wrapped around the substrates in step 2 than it is in step 1. Why is this? a. When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around the substrates. b. Generally, the size of a substrate is larger than the size of the active site into which it must fit. When the substrate enters the active site, the active site must stretch to fit. c. Before catalysis can occur, a substrate must change its shape so that it fits into the active site of the enzyme more precisely. d. Most active sites are only designed to hold one substrate. In this image, two substrates enter the active site, creating a tighter fit.

d. producing heat to increase the frequency of molecular collisions

42. Which of the following strategies is not used by cells to help enzymes and substrates find each other? a. locating enzymes used in the same biochemical pathway near each other in the cytoplasm b. having certain reactions occur within a specific organelle c. embedding more enzymes in the plasma membrane d. producing heat to increase the frequency of molecular collisions

c. these enzymes are involved in the same metabolic pathway and keeping them closer together increases the efficiency of the pathway.

43. In many organelles, groups of different enzymes are located on membranes in close proximity to each other because a. attaching enzymes to the membrane prevents the cell from losing them to the surrounding environment. b. when enzymes are in close proximity, each one can catalyze more than one type of reaction. c. these enzymes are involved in the same metabolic pathway and keeping them closer together increases the efficiency of the pathway. d. all enzymes must act in groups to sufficiently reduce the amount of activation energy required for a reaction to occur.

c. Three enzymes would be required.

44. The sequential reaction pathway A B C D is dependent on enzymes for each separate step. How many different enzymes would be required to produce D if starting with A? a. Just one used over and over for each step. b. Two; one for the A to B conversion and one for the C to D conversion. c. Three enzymes would be required. d. Four enzymes would be required.

a. B is the product of the activity of E2 and the substrate of E3.

45. In the figure below, E1, E2, and E3 represent three enzymes in the membrane of a mitochondrion. Which of the following is true? a. B is the product of the activity of E2 and the substrate of E3. b. If E2 does not function properly, A will not be produced. c. E2 is the product of E1 and the substrate of E3. d. C is the substrate of E1.

c. The metabolic rates of different tissues vary; the male body consists of a high percentage of energy-consuming muscle.

46. Comparative studies have repeatedly shown that smaller animals have faster metabolic rates than larger animals, yet human males are both larger and have a higher average BMR than human females. What explains the variation in the pattern? a. Males typically weigh more than females; when standardized for body weight the average BMR is identical for both genders. b. The large average body size of males reduces the surface area to volume ratio; body systems elevate their metabolic rates to compensate for the change. c. The metabolic rates of different tissues vary; the male body consists of a high percentage of energy-consuming muscle. d. Males have larger digestive systems, ingest more per meal, and metabolize food at a higher rate to maintain body weight homeostasis.

a. simply eating less and exercising more.

47. The application of modern biological research methods have shown that the most successful strategy for permanent weight loss almost always involves a. simply eating less and exercising more. b. consuming BMR activators (supplements that elevate the basal metabolic rate) like caffeine. c. body composition changes, particularly changing connective tissue to muscle. d. altering the body surface area to volume ratio.

c. amount of energy needed to raise the temperature of one liter of water by 1°C.

48. A calorie represents the a. number of grams of fat in a food product. b. number of times an enzyme can be reused before it must be replaced. c. amount of energy needed to raise the temperature of one liter of water by 1°C. d. temperature at which a gram of food is completely converted into carbon dioxide.

d. all of the above

49. If provided with the proper conditions, enzymes recovered from living tissues can be used in cell-free industrial processes; for example, a. the addition of amylases, lipases, and proteases can improve a detergent's ability to remove stains from clothing. b. cellulases and pectinases can digest the polysaccharides in fruit juice, producing a clarified product that is more appealing to consumers. c. the proteases in pineapple and papaya can tenderize meat by digesting the large fibrous proteins like collagen. d. all of the above

c. heat.

5. Living systems must work to remain ordered. They pass off their disorder in the form of a. light. c. heat. b. sound. d. water.

c. Exercise produced an almost immediate positive metabolic effect in which the strength and duration was proportional to the fitness level; exercise was beneficial to all participants.

50. Physiologists monitored metabolite concentrations generated during exercise in three groups of individuals (those with poor fitness, average fitness, and exceptional fitness); which statement best summarizes their findings? a. Exercise was beneficial to all groups, but those benefits concluded immediately upon cessation of the exercise; to be significantly beneficial, the duration of exercise must be lengthened. b. The metabolic responsiveness of unfit individuals was extremely low; unfit individuals are unlikely to experience benefits from exercise for at least 30 days after starting an exercise program. c. Exercise produced an almost immediate positive metabolic effect in which the strength and duration was proportional to the fitness level; exercise was beneficial to all participants. d. Metabolites extracted from the blood of unfit individuals was shown to suppress the level of metabolism of cells growing in tissue culture.

c. carbon cycling.

6. The reuse of the same carbon molecules by plants, animals, and their environments through time is known as a. activation energy. c. carbon cycling. b. a consumption tree. d. the third law of thermodynamics.

a. sugars.

7. Photosynthetic organisms capture energy from sunlight and convert it into chemical bonds by forming a. sugars. c. work. b. enzymes. d. heat.

a. potential energy.

8. During photosynthesis, light energy is converted into chemical energy, a type of a. potential energy. c. heat. b. kinetic energy. d. metabolism.

b. provided by carbon dioxide.

9. In photosynthesis, the carbon used to make sugars is a. provided by enzymes. c. extracted from DNA. b. provided by carbon dioxide. d. oxidized to make sugars.