AP Biology Practice Exam #3
Subunit #3: Cellular Energetics
_____1. Which form of energy is Not correctly associated with an example?
a) kinetic energy : fat molecules
b) kinetic energy : movement of muscles
c) chemical energy : glucose
d) potential energy : water held behind a dam
e) potential energy : ATP
_____2. Which Best describes the first law of thermodynamics?
a) Energy is not created nor destroyed, but it can change into matter.
b) Energy is not created nor destroyed, but it can change from one energy form to another.
c) Energy can be created from matter or used to produce matter.
d) Some useful energy is lost as heat whenever an energy transfer occurs.
e) Energy transfers are always 100% efficient in changing energy from one useful form to another.
_____3. Which Best describes the second law of thermodynamics?
a) Energy is not created nor destroyed, but it can change into matter.
b) Energy is not created nor destroyed, but it can change from one energy form to another.
c) Energy can be created from matter or used to produce matter.
d) Some useful energy is lost as heat whenever an energy transfer occurs.
e) Energy transfers are always 100% efficient in changing energy from one useful form to another.
_____4. Endergonic reactions
a) are always coupling reactions
b) have a negative change in free energy and occur spontaneously
c) can only occur if there is an input of energy
d) have products with less free energy than the reactants.
e) All of the above are correct.
_____5. The subunits from which ATP is made are
a) ADP and phosphate
b) FAD and NAD+
c) FAD and NADPH
d) ADP and FAD
e) ADP and NAD+
_____6. An enzyme is generally named by adding ____ to the end of the name of the _____.
a) "-ose". cell in which it is found
b) "-ase". cell in which it is found
c) "-ose". substrate
d) "-ase". substrate
e) "-ase". coenzyme
_____7. A coenzyme is
a) an ionic cofactor that interacts with an enzyme to allow it to work.
b) a protein cofactor that interacts with an enzyme to allow it to work.
c) a nonprotein organic cofactor that interacts with an enzyme to allow it to work.
d) an ionic cofactor that interacts with an enzyme to inhibit it.
e) a protein cofactor that interacts with an enzyme to inhibit it.
_____8. Consider this reaction. A + B  C + D + energy.
a) This reaction is exergonic.
b) An enzyme could still speed the reaction.
c) ATP is not needed to make the reaction go.
d) A and B are reactants; C and D are products.
e) All of these are correct.
Question 9 refers to the diagram below:
_____9. Which of the following is true about what is taking place in this reaction?
a) It is exergonic.
b) It is an anabolic reaction.
c) It requires the removal of a molecule of water.
d) It requires a net input of energy.
e) It forms two insoluble molecules.
_____10. An inhibitor that changes the overall shape and chemistry of an enzyme is known as a(n)
a) allosteric inhibitor b) competitive inhibitor c) steric inhibitor d) noncompetitive inhibitor e) None of the above.
_____11. The difference between NAD+ and NADP+ is that
a) only NAD production requires niacin in the diet.
b) one is an organic molecule and the other is inorganic because it contains phosphate.
c) one carries electrons to the electron transport system and the other carries them to synthetic reactions.
d) one is involved in cellular respiration and the other is involved in photosynthesis.
e) Both C and D are correct.
_____12. A student conducts an experiment to test the efficiency of a certain enzyme. Which of the
following protocols would probably Not result in a change in the enzyme's efficiency?
a) Bringing the temperature of the experimental setup from 20 degrees C to 50 degrees C.
b) Adding an acidic solution to the setup.
c) Adding more substrate but not enzyme.
d) Placing the substrate and enzyme in a container with double the capacity.
e) Adding enzyme but not substrate.
_____13. Sunlight arrives at a plant in units of light energy called
a) protons b) photons c) electrons d) wavelengths
_____14. Why are plants green?
a) They absorb only green wavelengths of light.
b) They absorb only yellow and blue wavelengths of light.
c) They reflect nearly all wavelengths of light.
d) They reflect green wavelengths of light.
e) They reflect yellow and blue wavelengths of light.
_____15. To what does the term stroma refer?
a) the double membrane of the chloroplasts
b) a flattened disk or sac in the chloroplast
c) a central fluid filled space in the chloroplast
d) the cytochrome system in the membranes of the thylakoids
e) a stack of thylakoid membrane structures
_____16. To what does the term grana refer?
a) the cytochrome system in the membranes of the thylakoids
b) a central fluid filled space in the chloroplast
c) a flattened disk or sac in the chloroplast
d) the double membrane of the chloroplasts
e) a stack of thylakoid membrane structures
Question 17 refers to the absorption spectrum for a newly discovered plant illustrated below:
_____17. According to the diagram, which wavelength of light is most effective for photosynthesis for this pigment?
a) red
b) orange
c) green
d) blue
e) violet
_____18. All of the following could reduce the yield of photosynthetic products EXCEPT
a) increased photorespiration
b) reduced carbon dioxide concentrations in the air spaces of the leaf
c) increased frequency of stomatal openings
d) fewer Calvin cycle enzymes
e) lower concentrations of carbon dioxide in the atmosphere
Questions 19-22 refer to molecules of the following substances:
a) Oxygen (02)
b) NADP
c) NAD
d) FADH2
e) Cytochrome
_____19. The final electron acceptor for cellular respiration
_____20. A membrane-bound electron carrier found in the electron transport systems of both aerobic respiration and photosynthesis
_____21. An intermediate electron acceptor for oxidations that occur in both glycolysis and in Krebs cycle reactions
_____22. Coenzyme that transfers electrons from the Krebs cycle to the mitochondrial electron-transport chain at a lower energy level than that of electrons
entering at the beginning of the chain
_____21. Which of these is most closely associated with the process of electron transport?
a) a stack of thylakoid membrane structures
b) a flattened disk or sac in the chloroplast
c) the double membrane of the chloroplasts
d) the cytochrome system in the membranes of the thylakoids
e) a central fluid filled space in the chloroplast
_____22. Which statement is Not true about the cyclic electron pathway?
a) It produces ATP.
b) It involves Photosystem I.
c) It produces NADPH.
d) It is believed to be the first of the two electron transport pathways to have developed.
_____23. Which statement is Not true about the noncyclic electron pathway?
a) It absorbs photons into Photosystem I.
b) It absorbs photons into Photosystem II.
c) It produces ATP.
d) It produces NADPH.
e) It produces carbohydrates through carbon dioxide fixation.
_____24. When the stomates in a leaf close, then
a) carbon dioxide in the air spaces in the leaf decreases.
b) oxygen in the air spaces in the leaf increases.
c) C3 plants carry on photorespiration. using oxygen and producing PGA and carbon dioxide.
d) all photosystems as well as photorespiration come to a halt.
e) A, B, and C are correct.
_____25. Which would be a CAM plant?
a) cactus b) corn c) rice d) wheat e) oak tree
Question 26 refers to the diagram below:
_____26. Which types of plants display this biochemical pathway?
a) CAM
b) C4
c) C3
d) None of these
e) All of these
_____27. Which of the following processes is carried out more efficiently by a C4 plant than by a C3 plant?
a) Transport of sugars b) Fixation of CO2
c) Photolysis
d) Light absorption e) Chemiosmotic coupling
_____28. This process has as its products NADP+ and ADP, and sugar.
a) glycolysis b) chemiosmosis c) fermentation d) Calvin cycle e) photolysis
_____29. Which of the following photosynthetic reactions is known to occur in the thylakoid membrane?
a) carbon fixation b) light reactions c) dark reactions d) Calvin cycle e) transpiration
_____30. On a sunny day, the closing of stomata in plant leaves result in
a) a decrease in CO2 intake
b) a shift from C3 photosynthesis to C4 photosynthesis
c) an increase in transpiration
d) an increase in the concentration of CO2 in mesophyll cells
e) an increase in the rate of production of starch
_____31. The products of the light reactions in photosynthesis are
a) oxygen and NADP+ b) water and NADPH c) oxygen and NADPH d) water and oxygen e) oxygen and NAD+
_____32. If 6 molecules of oxygen are released during photosynthesis, how many molecules of
carbon dioxide would be fixed?
a) 1
b) 3
c) 6
d) 12
e) 24
_____33. The O2 released during photosynthesis comes from
a) C6H12O6
b) RuBP (RuDP)
c) NADPH
d) H2O
e) CO2
_____34. The cyclic pathway of photosynthesis occurs because
a) The chloroplasts need to regenerate NAD+.
b) The Calvin cycle uses more ATP than NADPH.
c) It can occur in regions lacking light.
d) It is more efficient way to produce oxygen.
e) It is a more efficient way to produce the NADPH needed for the Calvin cycle.
_____35. Carbohydrate-synthesizing reactions of photosynthesis directly require
a) Chlorophyll and CO2 b) O2 and H2O
c) darkness
d) light
e) products of the light reactions
_____36. Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis?
a) The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored
in ATP and NADPH.
b) The light-dependent reactions occur in the cytoplasm, the light-independent reactions occur in the
chloroplasts.
c) The light-dependent reactions depend on the presence of both photosystems I and II; the light-independent
reactions require only photosystem I.
d) The light-dependent reactions utilize CO2 and H2O; the light-independent reactions produce CO2 and H2O.
e) The light-dependent reactions occur only during the day, the light-independent reactions occur only during
the night.
_____37. The carbon that makes up organic molecules in plants is derived directly from
a) combustion of fuels
b) carbon fixed in photosynthesis
c) carbon dioxide produced in photosynthesis
d) carbon in the lithosphere
e) coal mines
_____38. The light independent cycle of photosynthesis receives energy rich molecules from which of the following?
a) ATP from respiration
b) O2 and H2O from the light reaction
c) Pyruvate from glycolysis
d) NADPH from photosystem II
e) ATP and NADPH from the light dependent reactions
_____39. The oxygen produced in the experiment was a direct result of
a) splitting of water in photosystem II
b) oxygen released in photosystem I
c) atmospheric oxygen used as an electron acceptor in the electron transport system
d) oxygen released by the aerobic bacteria
e) oxygen released when the carbon dioxide was used in the Calvin Benson Cycle
Questions 40-44:
a) Glycolysis
b) Chemiosmosis
c) Krebs cycle (citric acid cycle)
d) Light-dependent reactions of photosynthesis
e) Calvin cycle (light-independent reactions of photosynthesis)
_____40. Process in which 02 is released as a by-product of oxidation-reduction reactions
_____41. Process in which CO2 is released as a by-product of oxidation-reduction reactions
_____42. Process in which carbon from CO2 is incorporated into organic molecules
_____43. Process found in both photosynthesis and cellular respiration
_____44. Process in which sugar is oxidized to pyruvic acid
____45. Which of the following pathways for the transformation of cellular energy most likely evolved first?
a) Glycolysis
b) C4 photosynthesis (c) Calvin cycle
d) Citric acid (Krebs) cycle
e) Cyclic photophosphorylation
_____46. Complete oxidative breakdown of glucose results in ____ ATP molecules.
a) 2
b) 4
c) 32
d) 36
e) 39
_____47. The first reaction in the Krebs cycle is binding
a) carbon dioxide to a four carbon molecule
b) carbon dioxide to a five carbon molecule
c) acetyl-CoA to a four carbon molecule
d) acetyl-CoA to a five carbon molecule
_____48. The first process in breaking down glucose is
a) glycolysis
b) the electron transport system
c) the Krebs cycle
d) fermentation
e) the transition reaction
_____49. Which process produces both NADH and FADH2?
a) glycolysis
b) the electron transport system
c) the Krebs cycle
d) fermentation
e) the transition reaction
_____50. The generation of hydrogen ion concentration gradients across membranes of the mitochondria is known as which theory of ATP production?
a) glycolytic
b) phosphate pump
c) chemiosmotic
d) negative ion generator
e) none of these
_____51. The greatest number of ATP molecules is produced in
a) alcoholic fermentation b) glycolysis
c) the Kreb’s cycle
d) lactic acid fermentation
e) aerobic electron transport
_____52. If fermentation follows glycolysis,
a) NO2 will be one of the products as pyruvate is converted to lactate.
b) The two NADH molecules produced during glycolysis will (depending on the organism) be used to reduce
pyruvate to either lactate (lactic acid) or ethanol and CO2
c) ATP will be required to convert pyruvate to either lactic acid or ethanol and CO 2
d) Oxidative phosphorylation occurs either on the plasma membrane or on derivatives of the plasma
membrane
_____53. The enzymes of the electron transport chain are bound to the surface of the cristae. The cristae
are folded inward in order to
a) decrease the intermembrane space
b) increase diffusion surface for glycolysis
c) separate the products from the substrate in the Krebs cycle
d) form a battery like "cells" for the electron transport chain
e) reduce the distance the FADH2 and NADH has to travel, and place the products of one reaction
near the enzymes for the next reaction
_____54. One turn of the Krebs cycle produces
a) 2 NADH, 2 FADH2, 2 ATP
b) 3 NADH, 1 FADH2, 1 ATP
c) 1 NADH, 3 FADH2, 2 ATP
d) 3 NADH, 2 FADH2, 1 ATP
e) 3 NADH, 1 FADH2, 2 ATP
_____55. Acetyl-CoA is produced from
a) pyruvate and a coenzyme
b) citric acid and a coenzyme
c) ATP and pyruvate
d) carbon dioxide and pyruvate
e) citric acid and carbon dioxide
_____56. The primary energy carrier between the Krebs cycle and the electron transport system is
a) NADH
b) ADP
c) FADH2
d) water (H2O)
e) carbon dioxide (CO2)
_____57. Which of the following statements about mitochondrial chemiosmosis is NOT true?
a) The potential energy released from the mitochondrial proton gradient is used to produce ATP.
b) The mitochondrial proton gradient provides energy for muscle contraction.
c) Proteins embedded in the inner mitochondrial membrane play an important role in ATP synthesis.
d) Heat energy is required to establish the electron transport chain.
e) A proton gradient is established across the inner membrane of the mitochondrion.
_____58. Which metabolic process is common to both aerobic cellular respiration and alcoholic fermentation?
a) Krebs cycle
b) Glycolysis
c) Production of a proton gradient d) Electron transport chain
e) Conversion of pyruvic acid to acetyl CoA
_____59. Which of the following directly produces the most ATP per mole of glucose during aerobic cellular respiration?
a) Glycolysis
b) Substrate-level phosphorylation
c) Kreb’s cycle
d) Alcoholic fermentation
e) Electron transport chain and chemiosmosis
______60. The function of which of the following organelles directly requires oxygen?
a) Golgi apparatus
b) Ribosome
c) Mitochondrion
d) Nucleus
e) Centriole
_____61. Oxygen consumption can be used as a measure of metabolic rate because oxygen is
a) required by all living organisms
b) required to break down the ethanol that is produced in muscles
c) necessary for ATP synthesis by oxidative phosphorylation
d) necessary to replenish glycogen levels
e) necessary for fermentation to take place
_____62. The antibiotic oligomycin directly inhibits the function of ATP synthases and does not allow hydrogen ions to flow back through the inner
mitochondrial membrane. What are the immediate consequences of this toxin?
a) A proton gradient does not develop.
b) ATP is not formed.
c) NADH and FADH are not oxidized.
d) Protons are not pumped across the membrane.
e) Hydrogen ions leak into the intermembrane space.
_____63. For fatty acids to be able to enter the pathways of cellular respiration, they must be
a) deaminated
b) combined with glycerol
c) combined with ATP
d) broken into acetyl groups
e) be converted into five carbon sugars
_____64. The amino acids we cannot synthesize are called ____ because _____.
a) unnecessary, therefore we do not need them
b) limiting, they must be included in our diet
c) anabolic, they must use alternative amino acids
d) essential, they must be included in our diet
e) superfluous, they must survive without them
_____65. Which of the following occurs in both cellular respiration and photosynthesis?
a) Calvin cycle
b) Chemiosmosis
c) Citric acid cycle
d) Krebs cycle
e) Glycolysis
_____66. What is the cause of cramps you feel in your muscles during strenuous exercise?
a) Lactic acid fermentation
b) Alcohol fermentation
c) Chemiosmotic coupling
d) Too much oxygen delivery to the muscles
e) Oxidative phosphorylation
_____67. What is the purpose of oxygen (O2) in aerobic respiration?
a) Oxygen accepts electrons at the end of the electron transport chain.
b) Oxygen is necessary to carry away the waste carbon dioxide.
c) Oxygen is used in the formation of sugar molecules.
d) The oxygen molecule becomes part of the ATP molecule.
e) Oxygen donates H+ used in the formation of NADH.
_____68. Substrate level phosphorylation takes place in
a) glycolysis and the Krebs cycle
b) the electron transport system and the transition reaction
c) glycolysis and the electron transport system
d) the Krebs cycle and the transition reaction
e) Both B and D are correct.
_____69. The enzyme ATP synthase is responsible for making ATP and is found in large quantities embedded in mitochondrial
and chloroplast membranes. Peter Mitchell proposed the idea of chemiosmosis to help explain ATP synthesis. Choose the
answer that best completes the following sentence: Hydrogen ions are driven from the mitochondrial ____ to the inner membrane
space by the power of the _____ and then flow down a gradient through ATP synthase, phosphorylating ADP to produce ATP.
a) cristae; ATP
b) matrix; ATP
c) cristae; electron transport chain
d) matrix; electron transport chain
e) matrix; cristae
_____70. At the end of glycolysis, each molecule of glucose has yielded 2 molecules of _____,
2 molecules of ____, and a net of 2 molecules of _____.
a) lactic acid; NADH; ATP
b) ethanol; NAD+; ATP
c) pyruvate; NADH; ADP
d) pyruvate; NAD+; ADP
e) pyruvate; NADH; ATP
_____71. Chemiosmosis occurs in
a) mitochondria only
b) nuclei only
c) ribosomes only
d) chloroplasts only
e) In both mitochondria and chloroplasts.
_____72. During respiration, most ATP is formed as a direct result of the net movement of
a) potassium against a concentration gradient.
b) protons down a concentrated gradient.
c) electrons against a concentrated gradient.
d) electrons through a channel.
e) sodium ions into a cell.
_____73. During cellular respiration, ATP is generated by all of the following Except
a) glycolysis
b) oxidative phosphorylation
c) the Calvin-Benson cycle or Calvin cycle
d) biochemical pathways occurring in the cytoplasm
e) biochemical pathways occurring in the mitochondria