Ch3 Energy, Chemical Reactions, and Cellular Full Test Bank

Anatomy & Physiology, 3e (McKinley)

Chapter 3 Energy, Chemical Reactions, and Cellular Respiration

1) Stored energy is described as potential energy.

2) The energy of motion is known as ________ energy.

3) The sodium level inside and outside of a resting cell is an example of the

A) kinetic energy of sodium rushing out of a cell down its concentration gradient.

B) kinetic energy of the large difference in sodium concentration on the inside versus the outside of the cell.

C) potential energy of a concentration gradient, because sodium is more abundant outside the cell.

D) potential energy of an electron transport chain, because sodium has an extra electron to donate.

E) conversion of potential energy to kinetic energy, because sodium can never move across the cell membrane and must move across its surface.

4) The energy stored in a molecule's chemical bonds is a form of kinetic energy.

5) As a runner sprints down a track, her movement is an example of

A) potential energy.

B) mechanical energy.

C) heat.

D) radiant energy.

E) chemical energy.

6) ________ is a monomer that is stored as the polymer glycogen within the liver and muscle.

7) Compare and contrast chemical energy and radiant energy. Into which broad category of energy (kinetic or potential) does each fit? What are two examples of each type of energy that relate to human physiology?

8) Three molecules that are important energy storage locations in the body are

A) DNA, tRNA, and rRNA.

B) glucose, glucagon, and glycogen.

C) ATP, glycogen, and triglyceride.

D) ADP, DNA, and mRNA.

E) glucagon, insulin, and protein.

9) The propagation of an impulse along the axon of a neuron is considered electrical energy, a form of kinetic energy.

10) The form of kinetic energy that refers to the movement of electromagnetic waves is ________ energy.

11) Which is a form of energy that is generally unavailable to do any work?

A) Heat

B) Kinetic energy

C) Radiant energy

D) Sound energy

E) Mechanical energy

12) The first law of thermodynamics states that once energy is consumed, it can no longer be converted to any other form of energy.

13) According to the second law of thermodynamics, when energy is transformed from one kind to another,

A) some of it is converted to heat.

B) some energy is destroyed.

C) new energy is created.

D) homeostasis is maintained.

E) chemical bonds must be broken.

14) When we shiver on a cold day, the heat produced by muscle tissue is a demonstration of

A) radiant potential energy.

B) the first law of thermodynamics.

C) the second law of thermodynamics.

D) the creation of energy.

15) When a car burns gasoline, the majority of the gasoline's chemical energy is transformed to sound and heat.

16) When our inner ears convert sound energy into neural impulses or our retinas convert light into neural impulses,

A) no heat is generated, and so it is an exception to the first law of thermodynamics.

B) it is an exception to both laws of thermodynamics, because no usable energy is lost.

C) it is consistent with the second law of thermodynamics, but an exception to the first.

D) the conversion is consistent with both laws of thermodynamics.

17) Typically, synthesis reactions are endergonic.

18) Chemical reactions that release energy are called ________ reactions.

19) The reaction in which water and carbon dioxide combine to form carbonic acid is

A) irreversible, as carbonic acid rapidly causes a drop in pH.

B) reversible, and can proceed in either direction depending on the concentrations of the molecules.

C) exergonic, and is an important energy source within the body.

D) an exchange reaction in which protons are transferred between atoms.

E) a catabolic reaction in which the formation of a larger molecule can lead to an increase in cell size.

20) The building of complex molecules from simpler ones is described as

A) anabolism.

B) catabolism.

C) exergonic.

D) irreversible.

E) reversible.

21) When the body's digestive system breaks down starch, a complex carbohydrate, into simpler carbohydrates, the reaction is

A) anabolic and endergonic.

B) anabolic and exergonic.

C) catabolic and exergonic.

D) catabolic and endergonic.

22) Which one of the following choices includes three descriptions that are consistent with each other (that is, that describe the same type of chemical reaction)?

A) Anabolic, dehydration, endergonic

B) Exchange, hydrolysis, endergonic

C) Catabolic, dehydration, irreversible

D) Metabolic, synthesis, exergonic

E) Anabolic, catabolic, dehydration

23) The exchange of a phosphate group between creatine phosphate and adenosine diphosphate is categorized as a catabolic (rather than anabolic) reaction.

24) The term "metabolism" refers to

A) reactions involving the breakdown of complex molecules into simpler ones.

B) reactions involving the breakdown of complex molecules or the exchange of atoms between similarly sized reactants.

C) all the chemical reactions in the body.

D) reactions involving the synthesis of complex molecules from simpler ones.

E) digestive system reactions that are either catabolic or exchange reactions.

25) When NAD+ becomes NADH, it is being

A) reduced and gaining chemical energy.

B) reduced and releasing chemical energy.

C) oxidized and gaining chemical energy.

D) oxidized and releasing chemical energy.

26) In a chemical reaction where an electron is exchanged from one reactant to another, the structure that loses an electron is

A) analyzed.

B) catalyzed.

C) oxidized.

D) reduced.

27) In a redox reaction, when one reactant is oxidized, the other

A) is reduced.

B) is also oxidized.

C) is hydrolyzed into a smaller molecule.

D) releases chemical energy in the form of ATP.

E) becomes a larger, more complex molecule.

28) Generally, a cell stores enough ATP to meet the energy requirements of a few

A) seconds.

B) minutes.

C) hours.

D) days.

29) ATP formation

A) is endergonic and liberates energy for cellular processes that require energy.

B) is endergonic and requires the presence of fuel molecules such as glucose.

C) is exergonic and liberates energy for cellular processes that require energy.

D) is exergonic and requires the presence of fuel molecules such as glucose.

30) In a lab setting, heating a vessel full of reactants will generally

A) increase the kinetic energy of the molecules and increase the reaction rate.

B) raise the activation energy and catalyze the reaction.

C) lower the activation energy and the kinetic energy of the reactants.

D) convert products to reactants by increasing the energy requirements.

E) lower the reaction rate due to the change in structure of the reactants.

31) In order for a reaction to occur, energy is needed to break the bonds that already exist in the reactant molecules; that energy is called the ________ energy.

32) Explain the relationship between activation energy and reaction rate.  For example, how would an increase in activation energy affect reaction rate?  How do biological systems differ from lab settings when considering these chemical variables?

33) The term "activation energy" refers to the amount of energy

A) released by an exergonic reaction.

B) released by an endergonic reaction.

C) released by a catabolic reaction.

D) required to initiate any chemical reaction.

E) required to initiate only catabolic reactions.

34) A reaction with a very high activation energy should have a very high reaction rate.

35) The presence of an enzyme within a chemical system

A) increases activation energy.

B) decreases activation energy.

C) increases potential energy.

D) does not affect either activation energy or potential energy.

36) Enzymes are biological catalysts that are crucial for normal human metabolism.

37) Exergonic reactions do not require activation energy.

38) In the absence of the enzyme carbonic anhydrase, the combination of water and carbon dioxide to form carbonic acid does not occur.

39) Structurally, enzymes are generally

A) globular proteins.

B) fibrous proteins.

C) spherical carbohydrates.

D) elongated carbohydrates.

E) four-ring steroids.

40) The region of an enzyme into which the substrate fits is a

A) one-size-fits-all active site.

B) highly specific active site.

C) highly specific antibody.

D) one-size-fits-all antibody.

41) The enzyme-substrate complex is

A) another name for the active site.

B) the reactants whose chemical reaction the enzyme catalyzes.

C) the chemical structure formed when the substrate binds to the active site.

D) a pocket on the substrate that the enzyme recognizes.

42) Pancreatic amylase serves its function when it is located in the

A) mouth.

B) blood.

C) liver.

D) stomach.

E) small intestine.

43) Lactose intolerance is caused by the lack of the enzyme lactase, which is normally found in the

A) lumen of the stomach.

B) inside of cells of the liver and gall bladder.

C) membranes of cells in the small intestine.

D) inside of cells in the large intestine.

E) endothelium of capillaries in the large intestine.

44) The enzyme DNA polymerase is synthesized

A) at a ribosome, and it remains within the cell.

B) at the rough endoplasmic reticulum, and it is secreted from the cell.

C) at the Golgi apparatus, and it is embedded in the cell membrane.

D) in the nucleus, and it is converted to RNA for export outside the cell.

45) Which answer lists the steps of enzyme action in correct order?

A) Formation of enzyme-substrate complex, induced fit, formation or breakage of chemical bonds, release of product

B) Induced fit, formation of enzyme-substrate complex, formation or breakage of chemical bonds, release of product

C) Formation or breakage of chemical bonds, induced fit, formation of enzyme-substrate complex, release of substrate

D) Induced fit, formation or breakage of chemical bonds, formation of enzyme-substrate complex, release of product

46) When an enzyme's conformational change results in the enzyme hugging the substrate in its active site, the action is referred to as the ________ model of enzyme function.

47) When an enzyme catalyzing a catabolic reaction changes conformation to an induced fit with the substrate,

A) it strengthens the chemical bonds in the enzyme so that it remains perpetually active.

B) it stresses chemical bonds in the substrate, making it easier to break them.

C) it strengthens chemical bonds in the substrate so that cofactors can act on it.

D) it stresses chemical bonds in the enzyme so that the enzyme breaks into two catalytic subunits.

48) In the final step of enzymatic catalysis,

A) the substrate is released and the enzyme is inactivated.

B) the product is completed and the enzyme is inactivated.

C) the products are released and the enzyme is free to bind other substrates.

D) the enzyme and substrate form chemical bonds with each other resulting in a new product.

E) equilibrium is obtained so that the enzyme does not catalyze further reactions.

49) Cofactors are generally proteins.

50) Organic cofactors are referred to as ________.

51) In performing its enzymatic function, carbonic anhydrase

A) requires the inorganic coenzyme zinc.

B) requires the organic coenzyme carbon dioxide.

C) is facilitated by the inorganic coenzyme NAD+.

D) is facilitated by the organic coenzyme zinc.

E) requires the inorganic coenzyme NADPH.

52) Which enzyme class splits a chemical bond in the absence of water?

A) Ligase

B) Oxidoreductase

C) Lyase

D) Hydrolase

E) Dehydrogenase

53) Which enzyme class transfers electrons from one substance to another?

A) Oxidoreductase

B) Transferase

C) Isomerase

D) Ligase

E) Electin

54) An enzyme that is described as a protein kinase is a(n)

A) hydrolase that removes an amino acid from a protein.

B) transferase that transfers a phosphate group to a protein substrate.

C) ligase that adds an amino acid to a protein.

D) isomerase that changes one protein into another.

E) protease that transfers electrons from one protein to another.

55) Lactase is an enzyme that digests lactose.

56) Briefly describe how enzymes are named. What is generally used for the root of the name, and what is generally used as the suffix? Provide one example.

57) An isomerase bonds two similar molecules together to form a larger one.

58) Both pepsin and trypsin are proteins that digest proteins.

59) Which statement accurately describes the effects of substrate and enzyme concentrations on reaction rate?

A) An increase in either substrate or enzyme concentration will increase the reaction rate.

B) An increase in either substrate or enzyme concentration will decrease the reaction rate.

C) An increase in substrate concentration increases the reaction rate, but enzyme concentration has no effect.

D) A decrease in substrate concentration or an increase in enzyme concentration increases the reaction rate.

E) An increase in substrate concentration or a decrease in enzyme concentration will increase the reaction rate.

60) Saturation occurs when

A) there is so much enzyme present that the reaction rate decreases if more is added.

B) all enzymes are busy and further increases in substrate concentration will not increase reaction rate.

C) enzymes become fatigued and can no longer catalyze changes in the substrate.

D) intramolecular interactions are disrupted in the enzyme, decreasing its efficiency and decreasing reaction rate.

E) the substrate is denatured and the enzyme cannot catalyze any changes in its structure.

61) Generally, a decrease in substrate concentration leads to an increase in reaction rate.

62) Enzyme saturation occurs when substrate levels are so high that all enzyme molecules are actively engaged in the chemical reaction, and so further increases in substrate concentration do not increase reaction rate.

63) At temperatures above 40°C (104°F) in the human body,

A) enzymatic reactions with substrates are more quickly catalyzed.

B) enzymes denature and reaction rates decrease.

C) protein flexibility is optimum and reaction rates increase.

D) protein shape is rigid and reaction rates are constant.

64) A fever of 101°F causes most enzymes in the human body

A) to denature.

B) to become more rigid.

C) to be more flexible and efficient.

D) to saturate.

65) Extremely high temperatures break intramolecular interactions and ________ an enzyme, resulting in a loss of its function.

66) Cold temperatures (below 36°C) denature proteins, which is why biochemistry labs never freeze enzymes.

67) The optimal pH range for most human enzymes is

A) 1–2.

B) 4–6.

C) 6–8.

D) 8–10.

E) 13–14.

68) The optimal pH range for the stomach enzyme pepsin is

A) 2–4.

B) 6–8.

C) 7.3–7.4.

D) 10–12.

E) 12.0–13.5.

69) The less acidic (more basic) the environment is, the more efficient an enzyme will be.

70) A large decrease in pH results in increased H+ binding to an enzyme, which can disrupt electrostatic interactions within the molecule.

71) A substance that binds to the active site of an enzyme and turns it off is called a(n) ________ inhibitor.

72) Noncompetitive inhibition of an enzyme occurs when the inhibitor binds to the

A) allosteric site, and its effectiveness is not influenced by substrate concentration.

B) allosteric site, and its effectiveness depends on substrate concentration.

C) active site, and its effectiveness is not influenced by substrate concentration.

D) active site, and its effectiveness depends on substrate concentration.

E) substrate, and its effectiveness depends on product concentration.

73) Allosteric inhibitors are also called noncompetitive inhibitors.

74) When multiple enzymes are organized in a metabolic pathway, each enzyme catalyzes one reaction and then releases the product.

75) A group of enzymes that are physically attached to one another is referred to as a(n)

A) allosteric pathway.

B) metabolic pathway.

C) multienzyme complex.

D) phosphate complex.

76) Which enzyme system allows for regulation at a single site and also diminishes the chance that a needed substrate will diffuse away from a catalyst?

A) Metabolic pathway

B) Multienzyme complex

77) To prevent depletion of a substrate, the product of a metabolic pathway will

A) turn off an enzyme early in the pathway.

B) catalyze its own production.

C) increase enzyme activity through positive feedback.

D) occupy the active site of an enzyme early in the pathway.

78) In the regulation of enzymes, negative feedback ensures that a lot of product can be made from only a little bit of substrate.

79) Enzymes that remove phosphate groups from their substrates are called ________.

80) Enzyme regulation by negative feedback involves

A) allosteric inhibition of an enzyme by a product of its metabolic pathway.

B) allosteric facilitation of an enzyme by a substrate of its metabolic pathway.

C) allosteric modification of a substrate by an enzyme of an alternate metabolic pathway.

D) occupation of the active site of an enzyme so that it catalyzes less efficiently.

E) enhancement of the active site by a negatively charged substrate.

81) A protein kinase is an enzyme that adds a phosphate to its substrate.

82) Phosphorylation is carried out by a

A) kinase, and it results in the negative feedback inhibition of an enzyme.

B) kinase, and it may activate some enzymes and inhibit others.

C) phosphatase, and it results in the negative feedback inhibition of an enzyme.

D) phosphatase, and it may activate some enzymes and inhibit others.

83) Imagine that you discovered an enzyme in the human stomach that turned the substrate "ABC" into the product "XYZ".  Name this enzyme (using the standard convention) and describe its chemical characteristics.  Under what conditions would it be an effective catalyst?  How might its activity be regulated?

84) When one glucose molecule is fully oxidized, how many molecules of CO2 result?

A) 1

B) 2

C) 3

D) 6

85) During cellular respiration, when glucose is fully disassembled to carbon dioxide and water, the other reactant (with glucose) in the chemical equation is ________.

86) Glucose oxidation is exergonic.

87) In substrate-level phosphorylation, energy is first released to coenzymes and then transferred to form ATP.

88) The indirect method of ATP production involves coenzymes such as FAD and is referred to as ________ phosphorylation.

89) The more common way that ATP is produced in cells is

A) the indirect pathway known as oxidative phosphorylation.

B) the indirect pathway known as substrate-level phosphorylation.

C) the direct pathway known as oxidative phosphorylation.

D) the direct pathway known as substrate-level phosphorylation.

90) Which of the following choices lists the order of stages of cellular respiration in proper order?

A) Glycolysis, intermediate stage, citric acid cycle, and the electron transport system

B) Citric acid cycle, glycolysis, intermediate stage, and the electron transport system

C) Glycolysis, citric acid cycle, intermediate stage, and the electron transport system

D) Glycolysis, intermediate stage, electron transport system, and the citric acid cycle

E) Citric acid cycle, electron transport chain, intermediate stage, and glycolysis

91) The first stage of cellular respiration is

A) electron transport, and it occurs in the cytosol.

B) electron transport, and it occurs in the mitochondria.

C) glycolysis, and it occurs in the cytosol.

D) glycolysis, and it occurs in the mitochondria.

E) the citric acid cycle, and it occurs at the mitochondria.

92) Glycolysis requires oxygen.

93) The intermediate stage of cellular respiration

A) produces ATP and occurs in the cytosol.

B) produces carbon dioxide and occurs in the mitochondria.

C) requires Coenzyme A and occurs in the cytosol.

D) produces pyruvate and occurs in the mitochondria.

94) Hexokinase is an enzyme involved in cellular respiration and its substrate is glucose.  Considering this information, hexokinase must be located

A) in the lumen of the stomach.

B) in the lumen of the small intestine.

C) inside the mitochondria of cells.

D) in the cytosol of cells.

95) In the process of glycolysis

A) one enzyme converts glucose into NADH.

B) two enzymes are involved in breaking glucose down to ten pyruvate molecules.

C) ten enzymes are involved in breaking glucose down to two pyruvate molecules.

D) twelve enzymes split glucose into thirteen smaller molecules.

E) six enzymes use two ATP to split glucose in half.

96) Glycolysis results in the breakdown of a glucose molecule and the net production of four ATP molecules.

97) During the early steps of glycolysis, glucose is converted to glucose 6-P, and then glucose 6-P is converted directly to

A) aldolase.

B) fructose 6-P.

C) isomerase.

D) pyruvate.

E) NADH.

98) The binding of ATP to phosphofructokinase inhibits the glycolytic pathway.

99) If insufficient oxygen is available for the anaerobic breakdown of pyruvate, it is converted to ________.

100) Pyruvate dehydrogenase is located in the

A) cytosol.

B) cell membrane.

C) outer compartment of the mitochondrion.

D) middle of the crista.

E) matrix of the mitochondrion.

101) Which stage of cellular respiration is catalyzed by pyruvate dehydrogenase?

A) Electron transport system

B) Intermediate stage

C) Citric acid cycle

D) Glycolysis

E) Fermentation to lactate

102) Pyruvate dehydrogenase is a multienzyme complex that brings together a molecule of pyruvate and a molecule of coenzyme A.

103) During cellular respiration, decarboxylation occurs when

A) a carbon atom is removed from glucose.

B) a carbon dioxide molecule is removed from the cytosol.

C) a carboxyl group is released from pyruvate.

D) a carbon atom is removed from and an oxygen atom is added to fructose.

E) all carbon and oxygen atoms are released from a high-energy molecule.

104) Decarboxylation occurs during the intermediate stage of aerobic cellular respiration.

105) During decarboxylation, NAD+ is formed from NADH.

106) During the citric acid cycle, an acetyl CoA molecule produced in the intermediate stage combines with a molecule of

A) oxaloacetic acid.

B) pyruvate.

C) citrate.

D) succinate.

107) The citric acid cycle involves

A) a multienzyme complex within the cytosol.

B) several enzymes within the matrix of the mitochondrion.

C) a multienzyme complex within the outer compartment of the mitochondrion.

D) several enzymes within the cytosol and the outer membrane of the mitochondrion.

108) One turn of the citric acid cycle results in the formation of

A) 1 ATP, 3 NADH, and 1 FADH2.

B) 2 pyruvates and 2 ATP.

C) 2 ATP, 2 NADH+, and 3 FADH.

D) 2 citrates, 4 ATP, and 3 FADH2.

109) Oxidative phosphorylation within the electron transport system accounts for a little less than half of the ATP synthesized from the breakdown of glucose.

110) The coenzymes that will provide the electrons needed for the electron transport system are

A) NADH and FADH2.

B) NAD and FAD+.

C) acetyl CoA and citrate.

D) pyruvate and NADH.

E) FAD and decarboxylase.

111) The electron transport chain

A) does not require oxygen, and involves proteins in the outer membrane of mitochondria.

B) does not require oxygen, and involves proteins in the cristae of mitochondria.

C) requires oxygen, and involves proteins in the outer membrane of mitochondria.

D) requires oxygen, and involves proteins in the cristae of mitochondria.

112) The proteins in the electron transport chain transport H+

A) from the cytosol to the matrix.

B) from the matrix to the outer compartment.

C) from the outer compartment to the cytosol.

D) from the outer compartment to the matrix.

E) from the cristae to the matrix.

113) The enzyme that harnesses the energy of H+ diffusion down its concentration gradient within a mitochondrion to make high-energy molecules for the cell is

A) ATP phosphatase.

B) ATP synthase.

C) pyruvate decarboxylase.

D) succinic dehydrogenase.

E) creatine phosphatase.

114) In the first step of the electron transport chain, the coenzymes NADH and FADH2 are oxidized.

115) The net ATP available for a cell to use after glycolysis of one glucose molecule is ________.

116) The total number of ATP generated by the breakdown of glucose is 38, but the net number of ATP generated is

A) 2.

B) 24.

C) 30.

D) 36.

E) 40.

117) During electron transport, how many ATP can be generated from the energy contributed by a molecule of NADH?

A) 1

B) 2

C) 3

D) 30

E) 36

118) If oxygen is in short supply, the activity of the electron transport chain increases in order to compensate.

119) The reaction by which lactate is formed from pyruvate is catalyzed by lactate ________.

120) When oxygen is low, pyruvate is converted to lactate, while

A) NADH is converted to NAD+.

B) ATP is converted to AMP.

C) citrate is converted to pyruvate.

D) FADH is converted to NADH.

E) FADH2 is reduced to FAD+.

121) If oxygen levels drop such that glucose metabolism becomes primarily anaerobic, then the amount of ATP produced per glucose molecule will

A) increase slightly.

B) remain roughly the same.

C) be halved.

D) decrease to much less than half of what it was.

122) Diseases of the respiratory or circulatory systems that impair oxygen delivery to body cells will diminish ATP production in those cells.

123) At rest, muscle tissue prefers to use ________ molecules as sources of fuel.

A) pyruvate

B) fatty acid

C) insulin

D) protein

E) simple carbohydrate

124) Fatty acids enter the cell respiration pathway at

A) the citric acid cycle, once they have been converted to acetyl CoA.

B) glycolysis, once they have been converted to glucose.

C) electron transport chain, once they have been converted to NADH.

D) the intermediate stage, once they have been converted to pyruvate.

125) All amino acids enter the cellular respiration pathway at the citric acid cycle.

126) A chemical reaction occurs when chemical bonds in an existing molecule are broken and new ones are formed.

127) The breakdown of H2CO3 into CO2 and H2O is catalyzed by an enzyme called carbonic anhydrase. Which of the following is a reactant in this reaction?

A) H2CO3

B) Carbonic anhydrase

C) H2O