AP Bio Chapter 9
Location of oxidative phosphorylation
inner mitochondrial membrane
cellular respiration
the catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP
reduction
the complete or partial addition of electrons to a substance involved in redox reaction.
oxidation
the complete or partial loss of electrons from a substance involved in a redox reaction
reducing agent
the electron donor in a redox reaction
substrate-level phosphorylation
the enzyme-catalyzed formation of ATP by direct transfer of a phosphate group of ADP from an intermediate substrate in catabolism
proton-motive force
the potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions across a biological membrane during chemiosmosis
oxidative phosphorylation
the production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration
What is the product of fermentation in yeast and bacteria
ethanol
Which of these is NOT a product of the citric acid cycle? a) NADH + H⁺ b) CO₂ c) FADH₂ d) ATP e) acetyl CoA
3) acetyl CoA
NADP⁺
Nicotinamide adenine dinucleotide, a coenzyme that cycles easily between oxidized (NAD⁺) and reduced (NADH) states, thus acting as an electron carrier.
When the protein gramicidin is integrated into a membrane, an H⁺ channel forms and the membrane becomes very permeable to protons (H⁺ ions). If gramicidin is added to an actively respiring muscle cell, how would it affect the rates of electron transport, proton pumping, and ATP synthesis in oxidative phosphorylation? (Assume that gramicidin does not affect the production of NADH and FADH₂ during the early stages of cellular respiration.) Sort the labels into the correct bin according to the effect that gramicidin would have on each process. catergory: remains the same, decreases (or goes to zero), increases labels: electron transport rate, proton pumping rate, rate of oxygen uptake, rate of ATP synthesis, size of the proton gradient
Remains the same: electron transport rate, proton pumping rate, rate of oxygen uptake Decreases (or goes to zero): rate of ATP synthesis, size of the proton gradient Increases: none
Identify all correct statements about the basic function of fermentation. *The basic function of fermentation is the production of additional ATP by further oxidation of the products of glycolysis. * The basic function of fermentation is the regeneration of NAD⁺, which allows continued ATP production by glycolysis. * The basic function of fermentation is the production of ethyl alcohol or lactic acid.
The basic function of fermentation is the regeneration of NAD⁺, which allows continued ATP production by glycolysis.
aerobic respiration
a catabolic pathway for organic molecules, using oxygen as the final electron acceptor in an electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms
fermentation
a catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid
citric acid cycle
a chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA *derived from pyruvate) to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration
redox reaction
a chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another; short for reduction-oxidation reaction
ATP synthase
a complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.
beta oxidation
a metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA
electron transport chain
a sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP
How many NADH are produced by glycolysis? a) 2 b) 5 c) 4 d) 1 e) 3
a) 2
In glycolysis, what starts the process of glucose oxidation? a) ATP b) ADP c) hexokinase d) FADH₂ e) NADPH
a) ATP
In glycolysis, what starts the process of glucose oxidation? a) ATP b) ADP c) hexokinase d)FADH2 e) NADPH
a) ATP
In glycolysis, what starts the process of glucose oxidation? a) ATP b) ADP c) hexokinase d) FADH₂ e) NADPH
a) ATP
The rate of cellular respiration is regulated by its major product, ATP, via feedback inhibition. As the diagram shows, high levels of ATP inhibit phosphofructokinase (PFK), an early enzyme in glycolysis. As a result, the rate of cellular respiration, and thus ATP production, decreases. Feedback inhibition enables cells to adjust their rate of cellular respiration to match their demand for ATP. Suppose that a cell's demand for ATP suddenly exceeds its supply of ATP from cellular respiration. Which statement correctly describes how this increased demand would lead to an increased rate of ATP production? a) ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production. b) ATP levels would rise at first, decreasing the inhibition of PFK and increasing the rate of ATP production. c) ATP levels would fall at first, increasing the inhibition of PFK and increasing the rate of ATP production. d) ATP levels would rise at first, increasing the inhibition of PFK and increasing the rate of ATP production.
a) ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production.
Under anaerobic conditions (a lack of oxygen), glycolysis continues in most cells despite the fact that oxidative phosphorylation stops, and its production of NAD⁺ (which is needed as an input to glycolysis) also stops. The diagram illustrates the process of fermentation, which is used by many cells in the absence of oxygen. In fermentation, the NADH produced by glycolysis is used to reduce the pyruvate produced by glycolysis to either lactate or ethanol. Fermentation results in a net production of 2 ATP per glucose molecule. During strenuous exercise, anaerobic conditions can result if the cardiovascular system cannot supply oxygen fast enough to meet the demands of muscle cells. Assume that a muscle cells; demand for ATP under anaerobic conditions remains the same as it was under aerobic conditions. What would happen to the cell's rate of glucose utilization? a) Glucose utilization would increase a lot. b) Glucose utilization would increase a little. c) Glucose utilization would remain the same. d) Glucose utilization would decrease a little. e) Glucose utilization would decrease a lot.
a) Glucose utilization would increase a lot.
Gaseous hydrogen burns in the presence of oxygen to form water: 2H₂ + O₂→2H₂O + energy Which molecule is oxidized and what kind of bond is formed? a) Hydrogen, polar. b) Oxygen, polar. c) Hydrogen, nonpolar. d) Oxygen, nonpolar.
a) Hydrogen, polar.
In glycolysis in the absence of oxygen, cells need a way to regenerate which compound? a) NAD+ b) ethanol c) lactate d) carbon dioxide e) glucose
a) NAD⁺
In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs? a) Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH. b) Pyruvate is reduced and decarboxylated, and the resulting electrons oxidize an NAD+ to an NADH c) Pyruvate is oxidized and decarboxylated, and the resulting electrons are donated to NADH to produce NAD+. d) Pyruvate is reduced to acetyl-coA, which involves the reduction of pyruvate, the addition of a carbon dioxide from the environment, and its reduction by NADH. e) Pyruvate is ionized directly to acetyl-coA.
a) Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH.
In glycolysis, there is no production of carbon dioxide as a product of the pathway. Which of the following is the best explanation for this? a) The products of glycolysis contain the same total number of carbon atoms as in the starting material. b) There is very little ATP produced in glycolysis. c) The initial steps of glycolysis require an input of energy in the form of ATP (two per glucose). d) There are no oxidation or reduction reactions in glycolysis to produce CO2. e) Glucose contains more carbons than the number of carbons found in the pyruvate products that are produced by glycolysis.
a) The products of glycolysis contain the same total number of carbon atoms as in the starting material.
When solid tumors of animals reach a certain size, the center of the tumor begins to die. To prevent this, the tumor can recruit new blood vessels. What purpose does the recruitment of blood vessels to growing tumors serve? a) The second and third explanations together represent the best answer. b) It supplies a non-oxygen electron acceptor to cells so that the cells can respire anaerobically. c) It supplies oxygen so that aerobic cellular respiration can occur instead of fermentation. d) It supplies glucose to the rapidly dividing cells of the tumor. e) The first and second explanations together represent the best answer.
a) The second and third explanations together represent the best answer.
When protein molecules are used as fuel for cellular respiration, _____ are produced as waste. a) amino groups b) sugar molecules c) molecules of lactate d) fatty acids e) ethanol and CO2
a) amino groups
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step _____. a) enables the cell to make pyruvate into substances it can use b) prevents pyruvate from accumulating c) enables the cell to recycle the reduced NADH to oxidized NAD+ d) extracts a bit more energy from glucose e) removes poisonous oxygen from the environment
a) enables the cell to recycle the reduced NADH to oxidized NAD+
Of the metabolic pathways listed below, which is the only pathway found in all organisms? a) glycolysis b) cellular respiration c) the citric acid cycle d) the electron transport chain e) fermentation
a) glycolysis
In muscle cells, fermentation produces ______. a) lactate and NAD⁺ b) carbon dioxide, ethanol, and NAD⁺ c) pyruvate d) carbon dioxide, ethanol, NADH, and ATP e) lactate, NADH, and ATP
a) lactate and NAD⁺
During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction? a) oxygen b) water c) carbon dioxide d) glucose e) both glucose and carbon dioxide
a) oxygen
Most CO2 from catabolism is released during a) the citric acid cycle. b) oxidative phosphorylation. c) electron transport. d) glycolysis. e) lactate fermentation.
a) the citric acid cycle
In the citric acid cycle, for each pyruvate that enters the cycle, one ATP, three NADH, and one FADH2 are produced. For each glucose molecule that enters glycolysis, how many ATP, NADH, and FADH2 are produced in the citric acid cycle? a) two ATP, six NADH, two FADH2 b) three ATP, three NADH, one FADH2 c) one ATP, three NADH, one FADH2 d) about 38 ATP e) four ATP, six NADH, two FADH2
a) two ATP, six NADH, two FADH2
What is the product of aerobic oxidation
acetyl CoA
acetyl CoA
acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a fragment of pyruvate attached to a coenzyme
chemiosmosis
an energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. under aerobic conditions, most ATP synthesis in cells occurs by chemiosmosis.
cytochrome
an iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells.
facultative anaerobe
an organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present
Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other? a) Proton and electron. b) Anion and cation. c) Ionic and covalent. d) Polar and nonpolar.
b) Anion and cation.
Which term describes the degree to which an element attracts electrons? a) Oxidation. b) Electronegativity. c) Reduction. d) Polarity.
b) Electronegativity
Which of these is NOT a product of glycolysis? a) NADH b) FADH₂ c) ATP d) pyruvate
b) FADH₂
NADH and FADH₂ are both electron carriers that donate their electrons to the electron transport chain. The electrons ultimately reduce O₂ to water in the final step of electron transport. However, the amount of ATP made by electrons from an NADH molecule is greater than the amount made by electrons from an FADH₂ molecule. Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH₂? a) It takes more energy to make ATP from ADP and Pi using FADH₂ than using NADH b) Fewer protons are pumped across the inner mitochondrial membrane when FADH₂ is the electron donor than when NADH is the electron donor. c) FADH₂ is made only in the citric acid cycle while NADH is made in glycolysis, acetyl CoA formation, and the citric acid cycle. d) There is more NADH than FADH₂ made for every glucose that enters cellular respiration. e) The H⁺ gradient made from electron transport using NADH is located in a different part of the mitochondrion than the H⁺ gradient made using FADH₂.
b) Fewer protons are pumped across the inner mitochondrial membrane when FADH₂ is the electron donor than when NADH is the electron donor.
Why is the citric acid cycle a cyclic pathway rather than a linear pathway? In the oxidation of pyruvate to acetyl CoA, one carbon atom is released as CO2. However, the oxidation of the remaining two carbon atoms-in acetate- to CO2 required a complex, eight-step pathway-the citric acid cycle. Consider four possible explanations for why the last two carbons in acetate are converted to CO2 in a complex cyclic pathway rather than through a simple, linear reaction. Use your knowledge of the first three stages of cellular respiration to determine which explanation is correct. a) More ATP is produced per CO2 released in cyclic processes than in linear processes. b) It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA. c) Redox reactions that simultaneously produce CO2 and NADH occur only in cyclic processes. d) Cyclic processes, such as the citric acid cycle, require a different mechanism of ATP synthesis than linear processes, such as glycolysis.
b) It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA.
Which of the following statements is true of the bonds in a water molecule? a) The electron in each hydrogen atom is completely transferred to the oxygen atom, and each hydrogen atom has a net charge of +1. b) Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero. c) Oxygen acts as the electron acceptor and is oxidized. d) There is equal sharing of the electrons between the oxygen atom and the two hydrogen atoms, and the net charge is zero.
b) Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? a) The electrons gain free energy. b) The pH of the matrix increases. c) ATP synthase pumps protons by active transport. d) The cytochromes phosphorylate ADP to form ATP. e) NAD+ is oxidized.
b) The pH of the matrix increases.
During aerobic respiration, molecular oxygen (O2) is used for which of the following purposes? a) at the end of the citric acid cycle to regenerate citric acid b) at the end of the electron transport chain to accept electrons and form H2O c) between glycolysis and the citric acid cycle to split a carbon from pyruvate, producing CO2 d) as a source of O2 in every reaction that produces CO2 e) at the end of glycolysis to oxidize pyruvate
b) at the end of the electron transport chain to accept electrons and form H2O
In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in _____. a) ATP b) carbon dioxide c) oxygen gas d) NADH e) water
b) carbon dioxide
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? a) the citric acid cycle b) glycolysis c) reduction of pyruvate to lactate d) the electron transport chain e) synthesis of acetyl CoA from pyruvate
b) glycolysis
Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for a buildup of which of the following compounds? a) carbon dioxide b) lactate c) ADP d) oxygen e) ATP
b) lactate
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is a) pyruvate. b) oxygen. c) NAD+. d) water. e) ADP.
b) oxygen
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is a) water. b) oxygen. c) ADP. d) pyruvate. e) NAD⁺.
b) oxygen.
In the citric acid cycle, ATP molecules are produced by _______. a) photophosphorylation b) substrate-level phosphorylation c) photosynthesis d) oxidative phosphorylation e) cellular respiration
b) substrate-level phosphorylation
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes? a) oxidative phosphorylation b) the citric acid cycle c) anabolic pathways d) substrate-level phosphorylation e) glycolysis
b) the citric acid cycle
Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O2) and produces CO2? a) the citric acid cycle b) the combination of the citric acid cycle and electron transport c) glycolysis d) the electron transport chain e) the combination of glycolysis and the citric acid cycle
b) the combination of the citric acid cycle and electron transport
Where do the reactions of glycolysis occur in a eukaryotic cell? a) in the intermembrane space of the mitochondrion b) the cytosol c) across the inner membrane of the mitochondrion d) the inner membrane of the mitochondrion e) the matrix of the mitochondrion
b) the cytosol
In brewing beer, maltose (a disaccharide of glucose) is _____. a) one of the enzymes for alcoholic fermentation b) the substrate for alcoholic fermentation c) a substitute for pyruvate that cannot be made in yeast d) a sweetener e) the substrate for aerobic respiration
b) the substrate for alcoholic fermentation
In mitochondrial electron transport, what is the direct role of O₂? a) to provide the driving force for the synthesis of ATP from ADP and Pi b) to function as the final electron acceptor in the electron transport chain c) to oxidize NADH and FADH₂ from glycolysis, acetyl CoA formation, and the citric acid cycle d) to provide the driving force for the production of a proton gradient
b) to function as the final electron acceptor in the electron transport chain
A small amount of ATP is made in glycolysis by which of the following processes? a) attachment of a free inorganic phosphate (Pi) group to ADP to make ATP b) transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation c) harnessing energy from the sun d) transfer of electrons and hydrogen atoms to NAD+ e) transport of electrons through a series of carriers
b) transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the a) flow of electrons down the electron transport chain. b) affinity of oxygen for electrons. c) transfer of phosphate to ADP. d) H+ concentration across the membrane holding ATP synthase. e) oxidation of glucose and other organic compounds.
d) H+ concentration across the membrane holding ATP synthase.
Which of the following best describes the electron transport chain? a) Electrons are pumped across a membrane by active transport. b) Acetyl CoA is fully oxidized to CO2. c) Electrons are passed from one carrier to another, releasing a little energy at each step. d) Glucose is broken down to a three-carbon compound in preparation for the citric acid cycle. e) Hydrogen atoms are added to CO2 to make an energy-rich compound.
c) Electrons are passed from one carrier to another, releasing a little energy at each step.
When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle also eventually stop working. Which of the following is the best explanation for this? a) They run out of ADP. b) A high level of NADH is present in the cell. c) NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue. d) Electrons are no longer available from the electron transport chain to power glycolysis and the citric acid cycle. e) The uptake of oxygen stops because electron transport was inhibited.
c) NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue.
Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a one-hour class period in a classroom of 300 students if the heating and air conditioning is turned off and all doors are kept closed? a) Temperature goes down and carbon dioxide levels remain constant. This is because cellular respiration, being an endergonic reaction, requires an input of heat energy from the environment to occur and because carbon dioxide is neither produced nor consumed by cellular respiration. b) Neither temperature nor carbon dioxide levels change because cellular respiration is 100% efficient and because carbon dioxide produced by cellular respiration is just as rapidly consumed by cellular respiration. c) Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration. d) Temperature goes up but carbon dioxide levels remain constant because heat is a by-product of cellular respiration but carbon dioxide is converted to sugar during cellular respiration. e) Temperature goes up and the level of carbon dioxide goes down. This is because cellular respiration is an exergonic process that is only about 38% efficient; the remaining energy is lost to the environment as heat. Also, carbon dioxide is being converted to organic molecules such as fats and sugars during cellular respiration.
c) Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.
During respiration in eukaryotic cells, the electron transport chain is located in or on the _____. a) matrix of the mitochondrion b) cytosol c) inner membrane of the mitochondrion d) intermembrane space of the mitochondrion e) None of the listed responses is correct.
c) inner membrane of the mitochondrion
In mitochondria, exergonic redox reactions a) reduce carbon atoms to carbon dioxide. b) are directly coupled to substrate-level phosphorylation. c) provide the energy that establishes the proton gradient. d) are coupled via phosphorylated intermediates to endergonic processes. e) are the source of energy driving prokaryotic ATP synthesis.
c) provide the energy that establishes the proton gradient.
Location of glycolysis
cytosol
In glycolysis there is a net gain of ______ ATP. a) 3 b) 4 c) 5 d) 2 e) 1
d) 2
Which of the following statements is not true of most cellular redox reactions? a) Changes in potential energy can be released as heat. b) The reactant that is oxidized loses electrons. c) The electron acceptor is reduced. d) A hydrogen atom is transferred to the atom that loses an electron.
d) A hydrogen atom is transferred to the atom that loses an electron.
How would anaerobic conditions (when no O₂ is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATP synthesis in glycolysis or the citric acid cycle.) a) Neither electron transport nor ATP synthesis would be affected. b) Electron transport would stop but ATP synthesis would be unaffected. c) Electron transport would be unaffected but ATP synthesis would stop. d) Both electron transport and ATP synthesis would stop.
d) Both electron transport and ATP synthesis would stop.
A gram of fat oxidized by respiration produces approximately twice as much ATP as a gram of carbohydrate. Which of the following best explains this observation? a) Fats do not form true macromolecules as sugars do. b) Fats are produced when cells take in more food than they need. c) Fats are closely related to lipid molecules, the basic building blocks of cellular membranes. d) Fats are better electron donors to oxygen than are sugars. e) Fats are less soluble in water than sugars.
d) Fats are better electron donors to oxygen than are sugars.
Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops. Which of these statements is the correct explanation for this observation? a) ATP is needed to convert pyruvate to acetyl CoA. Without oxygen, no ATP can be made in oxidative phosphorylation. b) Oxygen is required to convert glucose to pyruvate in glycolysis. Without oxygen, no pyruvate can be made. c) Oxygen is an input to acetyl CoA formation. d) In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD⁺, which is needed for the first three stages of cellular respiration.
d) In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD⁺, which is needed for the first three stages of cellular respiration.
What kind of bond is formed when lithium and fluorine combine to form lithium fluoride? a) Nonpolar covalent. b) Redox. c) Polar covalent. d) Ionic.
d) Ionic
Most of the electrons removed from glucose by cellular respiration are used for which of the following processes? a) reducing NAD+ to NADH in glycolysis and the citric acid cycle b) producing a proton gradient for ATP synthesis in the mitochondria c) driving substrate-level phosphorylation in glycolysis d) The first two choices are correct. e) The second and third answers are correct.
d) The first two choices are correct.
Why is the citric acid cycle called a cycle? a) All of the carbon from glucose is cycled back into the atmosphere as carbon dioxide. b) NAD+ and FAD are recycled. c) NADH is cycled down the electron transport chain. d) The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle. e) The acetyl CoA that enters the cycle is regenerated in the last step of the pathway.
d) The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle.
Which of these enters the citric acid cycle? a) NADH + H⁺ b) G3P c) glucose d) acetyl CoA e) pyruvate
d) acetyl CoA
Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle? a) completion of substrate-level phosphorylation b) utilization of O2 c) formation of ATP d) formation of NADH and FADH2 e) formation of CO2
d) formation of NADH and FADH2
How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen? a) three b) two c) about 16 ATP d) four e) about 32 ATP
d) four
Of the following molecules in the glycolytic pathway (the process of glycolysis), the one with the most chemical energy is _____. a) glyceraldehyde-3-phosphate b) pyruvate c) glucose d) fructose-1,6-bisphosphate e) fructose-6-phosphate
d) fructose-1,6-bisphosphate
In the overall process of glycolysis and cellular respiration, _____ is oxidized and _____ is reduced. a) glucose ... ATP b) carbon dioxide ... water c) oxygen ... ATP d) glucose ... oxygen e) ATP ... oxygen
d) glucose...oxygen
A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to kill bacteria in people with infections. However, he cannot do this because _____. a) glycolysis can occur without the action of enzymes b) bacteria are prokaryotes; they usually don't need to perform glycolysis c) glycolysis produces so little ATP that the drug will have little effect d) human cells must also perform glycolysis; the drug might also poison them e) this step in the pathway of glycolysis can be skipped in bacteria, but not in humans
d) human cells must also perform glycolysis; the drug might also poison them
A molecule becomes more oxidized when it _____. a) gains an electron b) changes shape c) loses a hydrogen (H+) ion d) loses an electron e) gains a hydrogen (H+) ion
d) loses an electron
Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration? a) oxidation of pyruvate; citric acid cycle; oxidation of glucose to pyruvate; oxidative phosphorylation b) glycolysis; oxidative phosphorylation; citric acid cycle; oxidation of pyruvate. c) glycolysis; reduction of pyruvate; citric acid cycle; oxidative phosphorylation d) oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation e) oxidation of glucose to pyruvate; reduction of pyruvate; citric acid cycle; oxidative phosphorylation
d) oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
In fermentation _____ is reduced and _____ is oxidized. a) NADH...lactate b) lactate...ethanol c) lactate...NADH d) pyruvate...NADH e) NAD⁺...pyruvate
d) pyruvate...NADH
Muscle tissues make lactate from pyruvate to do which of the following? a) produce additional CO2 b) speed up the rate of glycolysis c) get rid of pyruvate produced by glycolysis d) regenerate NAD+ e) utilize the energy in pyruvate
d) regenerate NAD+
Which of the following accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle? a) regeneration of NAD+ b) removal of coenzyme A c) release of CO2 and release of coenzyme A d) release of CO2 and synthesis of NADH e) formation of CO2 and synthesis of ATP
d) release of CO2 and synthesis of NADH
In glycolysis, ATP molecules are produced by ______. a) photosynthesis b) photophosphorylation c) oxidative phosphorylation d) substrate-level phosphorylation e) cellular respiration
d) substrate-level phosphorylation
The ATP synthase in a human cell obtains energy for synthesizing ATP directly from which of the following processes? a) the oxidation of NADH and FADH2 b) the movement of electrons through a series of carriers c) the oxidation of glucose d) the flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme e) the reduction of oxygen
d) the flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme
Where do the reactions of the citric acid cycle occur in eukaryotic cells? a) across the inner membrane of the mitochondrion b) the cristae of the mitochondrion c) the cytosol d) the matrix of the mitochondrion e) the intermembrane space of the mitochondrion
d) the matrix of the mitochondrion
The overall efficiency of respiration (the percentage of the energy released that is saved in ATP) is approximately _____. a) 94% b) 0.5% c) 100% d) 2% e) 35%
e) 35%
In the combined processes of glycolysis and cellular respiration, what is consumed and what is produced? a) Water is consumed, and ATP is produced. b) Carbon dioxide is consumed, and water is produced. c) Oxygen is consumed, and glucose is produced. d) ATP is consumed, and oxygen is produced. e) Glucose is consumed, and carbon dioxide is produced.
e) Glucose is consumed, and carbon dioxide is produced.
Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 32 ATP from one glucose molecule. What happens to the rest of the energy in glucose? a) It is converted to starch. b) It is stored as fat. c) It is released as carbon dioxide and water d) It is used to make water from hydrogen ions and oxygen. e) It is converted to heat.
e) It is converted to heat.
A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose? a) It is stored in the ATP that was formed by glycolysis and the citric acid cycle. b) It is stored in pyruvate. c) It is stored in the carbon dioxide and water molecules released by these processes. d) It was lost as heat. e) It is stored in NADH and FADH₂
e) It is stored in NADH and FADH₂
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of _____. a) CO2 b) ATP c) acetyl CoA d) FADH2 e) NADH
e) NADH
If a compound that allows protons to freely diffuse across membranes is added to cells that are actively metabolizing glucose via cellular respiration, which of the following processes would stop? a) ATP synthesis b) glycolysis c) electron transport d) All of the listed responses are correct. e) None of the listed responses is correct.
e) None of the listed responses is correct.
Which process is the one in which glucose is oxidized to generate two molecules of pyruvate, and in which ATP and NADH are produced? a) the oxidation of pyruvate b) chemiosmosis c) fermentation d) the citric acid cycle e) None of the listed responses is correct.
e) None of the listed responses is correct.
If muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result? a) The muscle cells will have more trouble making enough ATP to meet their energy requirements. b) The cells will not be able to carry out oxidative phosphorylation. c) The cells will consume glucose at an increased rate. d) Only the first two answers are correct. e) The first three answers are correct.
e) The first three answers are correct.
If significant amounts of materials are removed from the citric acid cycle to produce amino acids for protein synthesis, which of the following will result? a) Less ATP will be produced by the cell. b) Less CO2 will be produced by the cell. c) The four-carbon compound that combines with acetyl CoA will have to be made by some other process. d) The first two answers are correct. e) The first three answers are correct.
e) The first three answers are correct.
Which of the following substances is/are involved in oxidative phosphorylation? a) ADP b) oxygen c) ATP d) None of the listed responses is correct. e) The first three listed responses are involved in oxidative phosphorylation.
e) The first three listed responses are involved in oxidative phosphorylation.
Which statement about the citric acid cycle is correct? a) The oxidation of compounds by the citric acid cycle requires molecular oxygen. b) the citric acid cycle depends on the availability of NAD⁺, which is a product of glycolysis. c) The citric acid cycle produces most of the ATP that is subsequently used by the electron transport chain. d) The citric acid cycle oxidizes glucose to carbon dioxide. e) The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.
e) The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.
Which of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria? a) ATP b) an ATP-dependent proton pump c) the components of the electron transport chain d) the production of NADH e) electrons moving down the electron transport chain
e) electrons moving down the electron transport chain
The function of cellular respiration is to _____. a) synthesize macromolecules from monomers b) extract CO2 from the atmosphere c) produce carbohydrates d) reduce CO2 e) extract usable energy from glucose
e) extract usable energy from glucose
Most of the ATP produced in cellular respiration comes from which of the following processes? a) reduction of NADH b) glycolysis c) substrate-level phosphorylation d) the citric acid cycle e) oxidative phosphorylation
e) oxidative phosphorylation
The energy given up by electrons as they move through the electron transport chain is used in which of the following processes? a) the oxidation of water b) the production of CO2 c) the production of NADH and FADH2 d) the breakdown of glucose e) pumping H+ across a membrane
e) pumping H+ across a membrane
What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ S Lactate + NAD+ a) NAD+ b) lactate c) NADH d) oxygen e) pyruvate
e) pyruvate
Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that _____. a) oxygen gas is composed of two atoms of oxygen b) oxygen is so abundant in the atmosphere c) oxygen acts as the final electron acceptor in cellular respiration d) oxygen gas contains a double bond e) the oxygen atom is very electronegative
e) the oxygen atom is very electronegative
alcohol fermentation
glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD⁺ and releasing carbon dioxide
lactic acid fermentation
glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD⁺ with no release of carbon dioxide
What is the product of fermentation in human muscle
lactate
Location of acetyl CoA formation
mitochondrial matrix
Location of citric acid cycle
mitochondrial matrix
In the last stage of cellular respiration, oxidative phosphorylation, all of the reduced electron carriers produced in the previous stages are oxidized by oxygen via the electron transport chain. The energy from this oxidation is stored in a form that is used by most other energy-requiring reactions in cells. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of oxidative phosphorylation. bin: net input, net output, not input or output compound: glucose, ADP,NAD⁺, pyruvate, ATP, NADH, O₂, CO₂, acetyl CoA, coenzyme A, water
net input: NADH, O₂, ADP net output: NAD⁺, ATP, water not input or output: glucose, CO₂, pyruvate, acetyl CoA, coenzyme A
In the citric acid cycle (also known as the Krebs cycle), acetyl CoA is completely oxidized. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of the citric acid cycle. bin: net input, net output, not input or output compound: NAD⁺, CO₂, glucose, acetyl CoA, ATP, pyruvate, ADP, NADH, O₂, coenzyme A
net input: NAD⁺, acetyl CoA net output: CO₂, ATP, NADH, coenzyme A not input or output: glucose, pyruvate, O₂
From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of glycolysis. Drag each compound to the appropriate bin. If the compound is not involved in glycolysis, put it to the "not input or output" bin. bin: net input, net output, not input or output compound: glucose, ADP,NAD⁺, pyruvate, ATP, NADH, O₂, CO₂, acetyl CoA, coenzyme A
net input: glucose, ADP, NAD⁺ net output: pyruvate, ATP, NADH not input or output: O₂, CO₂, acetyl CoA, coenzyme A
In acetyl CoA formation, the carbon-containing compound from glycolysis is oxidized to produce acetyl CoA. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of acetyl CoA formation. bin: net input, net output, not input or output compounds: pyruvate, CO₂, glucose, NAD⁺, acetyl CoA, ATP, coenzyme A, NADH, ADP, O₂
net input: pyruvate, NAD⁺, coenzyme A net output: CO₂, acetyl CoA, NADH not input or output: glucose, ATP, ADP, O₂
bin: reactants, products labels: pyruvate, lactate, NAD⁺, NADH
reactants: pyruvate, NADH products: lactate, NAD⁺
