Final 9
In glycolysis, as in all the stages of cellular respiration, the transfer of electrons from electron donors to electron acceptors plays a critical role in the overall conversion of the energy in foods to energy in ATP. These reactions involving electron transfers are known as oxidation-reduction, or redox, reactions. Drag the words on the left to the appropriate blanks on the right to complete the sentences.
1) Oxidized 2) Reduced 3) Glucose 4) Pyruvate 5) NAD⁺ 6) NADH
For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle (see the figure), what is the total number of NADH + FADH2 molecules produced?
12
How many NADH are produced by glycolysis?
2
In glycolysis there is a net gain of _____ ATP.
2
How many ATP are gained by substrate level phosphorylation from the complete breakdown of a single molecules of glucose in the presence of oxygen? 2 3 4 16 32
4
9.3- After pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation of organic molecules.
6 carbon dioxide release in complete oxidation glucoses. 2 pyruvates to acetyl CoA, carboxyl given off as 2 carbon dioxide. 4 carons are relased in citirc acid cylce as cirtate is oxiidized back to oxaloacetate.
Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C6H12O6) in aerobic cellular respiration?
60-64
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level? A. FADH2 B. ATP C. NADH D. ADP + P (i)
A
Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells? A. mitochondrial intermembrane space B. mitochondrial outer membrane C. cytosol D. mitochondrial matrix E. mitochondrial inner membrane
A
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. Both electron transport and ATP synthesis would stop. B. Electron transport would stop but ATP synthesis would be unaffected. C. Electron transport would be unaffected but ATP synthesis would stop. D. Neither electron transport nor ATP synthesis would be affected.
A
True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups. A. True B.False
A
True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria. A. True B. False
A
Where are the proteins of the electron transport chain located? A. mitochondrial inner membrane B. cytosol C. mitochondrial matrix D. mitochondrial intermembrane space E. mitochondrial outer membrane
A
Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell? A. Fermentation B. Krebs cycle C. Electron transport chain D. Glycolysis
A
Why is glycolysis considered to be one of the first metabolic pathways to have evolved? A. It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms. B. It produces much less ATP than does oxidative phosphorylation. C. It is found in prokaryotic cells but not in eukaryotic cells. D. It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.
A
Carbon atoms in acetyl CoA formation and the citric acid cycle During acetyl CoA formation and the citric acid cycle, all of the carbon atoms that enter cellular respiration in the glucose molecule are released in the form of CO2. Use this diagram to track the carbon-containing compounds that play a role in these two stages. Drag the labels from the left (which represent numbers of carbon atoms) onto the diagram to identify the number of carbon atoms in each intermediate in acetyl CoA formation and the citric acid cycle. Labels may be used more than once.
A) 2 C B) 6 C C) 6 C D) 5 C E) 4 C F) 4 C G) 4 C H) 4 C I) 4 C
3. The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is A. Oxygen B. Water C NAD plus D pyruvate
A. Oxygen
6. When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? A. The PH increases. B. ATP syntheses pumps proton by active transport. C. The electrons gain free energy. D. NAD plus oxidize
A. The PH increases.
In glycolysis, what starts the process of glucose oxidation?
ATP
Cellular respiration and a cell's demand for 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?
ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production.
9.1- Catabolic pathways yield energy by oxidizing organic fuels.
ATP produced by cellular respiration comes from oxidative phosphorylation. (Energy released from redox in electron transport chain) In substrate- level phosphorylation, enzyme transfer a phosphate group to ADP. ATP production in glycolysis occurs by substrate level phosphorylation and citric acid cycle.
9.5-Fermentation and anaerobic enable cell to produce ATP without use of oxygen.
Anaerobic yield more ATP. Substrate level phyosphorylaltion in glycolysis produce 2 ATP- fermentation. NADH passes high energy electrons to pyruvate, recycling NAD plus, and allow glycolysis to continue. In anerobic respiratio, the NADH proudced as pyruvate is oxidized as ATP. An electron chain captures energy of the electrons in NADH in rexod reaction.
During aerobic reaction, oxygen is used for
At the end of electron tranpsort chain to accept electrons and form water.
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 NADH and FADH2 C. It is stored in pyruvate. D. It is stored in the carbon dioxide and water molecules released by these processes. E. It was lost as heat.
B
An electron loses potential energy when it A. increases its activity as an oxidizing agent. B. shifts to a more electronegative atom. C. shifts to a less electronegative atom. D. moves further away from the nucleus of the atom. E. increases its kinetic energy.
B
If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and citric acid in the citric acid cycle shown in the accompanying figure? A. Oxaloacetate will decrease and citric acid will accumulate. B. Oxaloacetate will accumulate and citric acid will decrease. C. Both oxaloacetate and citric acid will accumulate. D. Both oxaloacetate and citric acid will decrease.
B
If you were to add one of the eight citric acid cycle intermediates to the culture medium of yeast growing in the laboratory, what do you think would happen to the rates of ATP and carbon dioxide production? A. The rate of ATP production would decrease, but the rate of carbon dioxide production would increase. B. The rates of ATP production and carbon dioxide production would both increase. C. There would be no change in ATP production, but we would observe an increased rate of carbon dioxide production. D. Rates of ATP and carbon dioxide production would probably both decrease.
B
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. Glucose is consumed, and carbon dioxide is produced. C. Oxygen is consumed, and glucose is produced. D. Carbon dioxide is consumed, and water is produced. E. ATP is consumed, and oxygen is produced.
B
Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration? A. ATP B. Carbon dioxide C. Water D. NADH
B
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. The citric acid cycle while NADH is made in glycolysis, acetyl CoA formation, and the citric acid cycle. B. Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor. C. 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. D. It takes more energy to make ATP from ADP and Pi using FADH2 than using NADH. E. There is more NADH than FADH2 made for every glucose that enters cellular respiration.
B
Substrate-level phosphorylation occurs _____. A. in the citric acid cycle B. in both glycolysis and the citric acid cycle C. in glycolysis D. during oxidative phosphorylation
B
When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes _____. A. hydrolyzed B. oxidized C. reduced D. an oxidizing agent
B
When electrons move closer to a more electronegative atom, what happens? A. The more electronegative atom is oxidized, and energy is consumed. B. The more electronegative atom is reduced, and energy is released. C. The more electronegative atom is reduced, and entropy decreases. D. The more electronegative atom is reduced, and energy is consumed. E. The more electronegative atom is oxidized, and energy is released.
B
Where is ATP synthase located in the mitochondrion? A. electron transport chain B. inner membrane C. cytosol D. outer membrane E. mitochondrial matrix
B
Which molecule is metabolized in a cell to produce energy for performing work? A. ATP B. Glucose C. ADP D. Phosphate
B
Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration? A. catabolism of sugars and related compounds B. transforming the energy in glucose and related molecules in a chemical form that cells can use for work C. the breakdown of glucose to carbon dioxide and water D. breaking down ATP, so that ADP and P can be reused E. producing complex molecules from chemical building blocks
B
Which of the following statements about the electron transport chain is true? A. Electrons gain energy as they move down the chain. B. NADH and FADH2 donate their electrons to the chain. C. The electron transport chain is the first step in cellular respiration. D. Water is the last electron acceptor.
B
Which stage of glucose metabolism produces the most ATP? A. Glycolysis B. Electron transport and chemiosmosis C. Krebs cycle D. Fermentation of pyruvate to lactate
B
Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy? A. The covalent bonds in organic molecules and molecular oxygen have more kinetic energy than the covalent bonds in water and carbon dioxide. B. Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O). C. The electrons have a higher potential energy when associated with water and CO2 than they do in organic compounds. D. The oxidation of organic compounds can be used to make ATP. E. The covalent bond in O2 is unstable and easily broken by electrons from organic molecules.
B
4. In mitochondria, exergonic redox reactions A. Are the source of energy driving prokaryotic ATP synthesis. B. Provide the energy that established the proton gradient. C. Reduce carbon atoms to carbon dioxide D. Are coupled via phosplaotylated intermediates to engerogic process.
B. Provide the energy that establised the proton gradient.
7. Most Carbon dioxide from catabolism is released during A. Glycolysis B the citric acid cycle. C lactate fermentation D electron transport
B. The ctirc acid cycle.
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.)
Both electron transport and ATP synthesis would stop.
The effects of anaerobic conditions 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.)
Both electron transport and ATP synthesis would stop.
A molecule that is phosphorylated A. has a decreased chemical reactivity; it is less likely to provide energy for cellular work. B. has less energy than before its phosphorylation and therefore less energy for cellular work. C. has an increased chemical potential energy; it is primed to do cellular work. D. has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate. E. has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate.
C
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? A. fermentation and glycolysis B. glycolysis and the oxidation of pyruvate to acetyl CoA C. oxidation of pyruvate to acetyl CoA and the citric acid cycle D. oxidative phosphorylation and fermentation
C
In fermentation _____ is reduced and _____ is oxidized. A. NADH ... lactate B. NAD+ ... pyruvate C. pyruvate ... NADH D. lactate ... ethanol E. lactate ... NADH
C
In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve? A. It allows for an increased rate of the citric acid cycle. B. It allows for an increased rate of glycolysis. C. It increases the surface for oxidative phosphorylation. D. It increases the surface for substrate-level phosphorylation.
C
In most cells, not all of the carbon compounds that participate in glycolysis and the citric acid cycle are converted to carbon dioxide by cellular respiration. What happens to the carbon in these compounds that does not end up as CO2? A. They are used to make NADH. B. They are used to make ATP from NADH. C. The carbon compounds are removed from these processes to serve as building blocks for other complex molecules. D. These carbon compounds are used to convert ADP to ATP via chemiosmosis. E. They are converted to heat energy.
C
The electrons stripped from glucose in cellular respiration end up in which compound? A. oxygen B. ATP C. water D. carbon dioxide E. NADH
C
The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol and the free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed? A. Most of the free energy available from the oxidation of glucose is used in the production of ATP in glycolysis. B. Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat. C. Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis. D. There is no CO2 or water produced as products of glycolysis.
C
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction A. gains electrons and gains potential energy. B. gains electrons and loses potential energy. C. loses electrons and loses potential energy. D. loses electrons and gains potential energy. E. neither gains nor loses electrons, but gains or loses potential energy.
C
The primary role of oxygen in cellular respiration is to A. combine with lactate, forming pyruvate. B. yield energy in the form of ATP as it is passed down the respiratory chain. C. act as an acceptor for electrons and hydrogen, forming water. D. combine with carbon, forming CO2. E. catalyze the reactions of glycolysis.
C
When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes A. hydrogenated. B. hydrolyzed. C. oxidized. D. an oxidizing agent. E. reduced.
C
Which of the following describes the process of glycolysis? A. Glycolysis occurs in the mitochondria. B. Glycolysis produces 30 ATP from each molecule of glucose. C. It represents the first stage in the chemical oxidation of glucose by a cell. D. It converts one glucose molecule to two molecules of pyruvate and carbon dioxide. E. It requires ATP and NADH.
C
Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water? A. oxidation of pyruvate to acetyl CoA B. fermentation C. oxidative phosphorylation (chemiosmosis) D. glycolysis E. citric acid cycle
C
Which of the following statements describes NAD+? A. In the absence of NAD+, glycolysis can still function. B. NAD+ can donate electrons for use in oxidative phosphorylation. C. NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. D. NAD+ is oxidized by the action of hydrogenases. E. NAD+ has more chemical energy than NADH.
C
Which statement about the citric acid cycle is correct? A. The citric acid cycle produces most of the ATP that is subsequently used by the electron transport chain. B. The citric acid cycle oxidizes glucose to carbon dioxide. C. The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle. D. The citric acid cycle depends on the availability of NAD+, which is a product of glycolysis. E. The oxidation of compounds by the citric acid cycle requires molecular oxygen.
C
Which step of the cellular respiration pathway can take place in the absence of oxygen? A. Electron transport chain B. Krebs cycle C. Glycolysis D. Fermentation
C
2. Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? A. The citric acid cycle. B.the electron transport chain. C. Glycolysis D. Reduction of pyruvate to lactate
C Glycolysis
Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
C6H12O6 is oxidized and O2 is reduced.
TP synthesis in glycolysis: substrate-level phosphorylation The ATP that is generated in glycolysis is produced by substrate-level phosphorylation, a very different mechanism than the one used to produce ATP during oxidative phosphorylation. Phosphorylation reactions involve the addition of a phosphate group to another molecule. Sort the statements into the appropriate bin depending on whether or not they correctly describe some aspect of substrate-level phosphorylation in glycolysis.
Correct: -One of the substrates is a molecule derived from the breakdown of glucose -An enzyme is required in order for the reaction to occur -A bond must be broken between an organic molecule and phosphate before ATP can form. Incorrect: -The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions. -The enyzmes involved in ATP synthesis must be attached to a membrane to produce ATP.
A young dog has never had much energy. He is brought to a veterinarian for help and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition? A. His cells lack the enzyme in glycolysis that forms pyruvate. B. His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA. C. His cells cannot move NADH from glycolysis into the mitochondria. D. His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
D
During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is A. transferred to ADP, forming ATP. B. used to phosphorylate fructose to form fructose 6-phosphate. C. transferred directly to ATP. D. retained in the two pyruvates. E. stored in the NADH produced.
D
In mitochondrial electron transport, what is the direct role of O2? A. to provide the driving force for the production of a proton gradient B. to provide the driving force for the synthesis of ATP from ADP and Pi C. to oxidize NADH and FADH2 from glycolysis, acetyl CoA formation, and the citric acid cycle D. to function as the final electron acceptor in the electron transport chain
D
In muscle cells, fermentation produces _____. A. lactate, NADH, and ATP B. pyruvate C. carbon dioxide, ethanol, NADH, and ATP D. lactate and NAD+ E. carbon dioxide, ethanol, and NAD+
D
The oxygen consumed during cellular respiration is involved directly in which process or event? A. the citric acid cycle B. the oxidation of pyruvate to acetyl CoA C. glycolysis D. accepting electrons at the end of the electron transport chain
D
What carbon sources can yeast cells metabolize to make ATP from ADP under anaerobic conditions? A. lactic acid B. either ethanol or lactic acid C. pyruvate D. glucose E. ethanol
D
When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the _____. A. lowering of pH in the mitochondrial matrix B.reduction of NAD+ C. formation of ATP D. creation of a proton-motive force
D
Which of the following statements about NAD+ is true? A. NAD+ can donate electrons for use in oxidative phosphorylation. B. In the absence of NAD+, glycolysis can still function. C. NAD+ has more chemical energy than NADH. D. NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.
D
5.oxidizing agent: Pyruvate+ NADH+H = lactate+ NAD plus A. Oxygen B.NADH C. Lactate D.pyruvate
D. Pyruvate
During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of the water come from? A. carbon dioxide (CO2) B. glucose (C6H12O6) C. pyruvate (C3H3O3−) D. lactate (C3H3O3−) E. molecular oxygen (O2)
E
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level? A. ADP + i B. NADH C. ATP D. NAD+ E. FADH2
E
In glycolysis, for each molecule of glucose oxidized to pyruvate A. two molecules of ATP are used and two molecules of ATP are produced. B. four molecules of ATP are used and two molecules of ATP are produced. C. six molecules of ATP are used and six molecules of ATP are produced. D. two molecules of ATP are used and six molecules of ATP are produced. E. two molecules of ATP are used and four molecules of ATP are produced.
E
Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle? A. succinyl CoA B. pyruvate C. α-ketoglutarate D. malate or fumarate E. acetyl CoA
E
Where does glycolysis take place in eukaryotic cells? A. mitochondrial outer membrane B. mitochondrial matrix C. mitochondrial inner membrane D. mitochondrial intermembrane space cytosol
E
Which of the following most accurately describes what is happening along the electron transport chain in the figure? A. Energy of the electrons increases at each step. B. Molecules in the chain give up some of their potential energy. C. Chemiosmosis is coupled with electron transfer. D. ATP is generated at each step. E. Each electron carrier alternates between being reduced and being oxidized.
E
Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide?
Enables the cell to recycle the reduced NADH to oxdized NAD plus.
Which of these is NOT a product of glycolysis?
FADH2
Comparing the amount of ATP synthesis from NADH and 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?
Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor
Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2?
Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.
8. In overall process of glycolysis and cellular respiration, ...... is oxidized and .......is reduced. Glucose- oxygen Oxygen- ATP ATP- Oxygen Carbon dioxide-water Glucose -ATP
Glucose -oxygen
Fermentation - ATP production in the absence of oxygen 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 cell's 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?
Glucose utilization would increase a lot.
Which metabolic pathways is the only pathway in all organism
Glycolysis
Cellular locations of the four stages of cellular respiration Each of the four stages of cellular respiration occurs in a specific location inside or outside the mitochondria. These locations permit precise regulation and partitioning of cellular resources to optimize the utilization of cellular energy.
Glycolysis - Cytosol Acetyl CoA - Mitochondrial matrix Citric acid cycle - Mitochondrial matrix Oxidative phosphorylation - inner mitochondrial membrane
Match each stage of cellular respiration with the cellular location in which it occurs. Labels may be used once, more than once, or not at all.
Glycolysis - Cytosol acetyl CoA - Mitochondrial matrix citric acid cycle - Mitochondrial matrix oxidative phosphorylation - inner mitochondrial membrane
1. The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the A. Oxidation of glucose and other organic compounds. B. Flow of electron down the electron transport chain. C. H ion concentration gradient across the membrane holding ATP synthase. D. Transfer of phosphate to ADP.
H ion concentration gradient across the membrane holding ATP synthase.
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the
H+ concentration across the membrane holding ATP synthase.
Why a chemist cannot use drug in glycolysis?
Human cells must also perfrom glycolysis, the drug might also poison them
Anaerobic conditions and acetyl CoA formation 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?
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.
citric acid cycle
Input acetyl enzyme A, ADP, NAD plus Output Cozyme A, Carbon dioxide, ATP, NADH
glycolysis
Input: NAD plus, ADP, gluocse Output: NADH, ATP,pyruvate
acetyl CoA formation
Input: NAD plus, co-enzyme A, pyruvate Output: NADH, acetyl enzyme A, carbon dioxide.
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 requires 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.
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.
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 requires 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.
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.
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?
It is stored in NADH and FADH2
Which of the following describes the process of glycolysis?
It represents the first stage in the chemical oxidation of glucose by a cell.
Why is glycolysis described as having an investment phase and a payoff phase?
It uses stored ATP and then forms a net increase in ATP.
Match each product of pyruvate metabolism with the condition under which it is produced.
Lactate: fermentation in human muscle Ethanol: fermentation in yeast and bacteria Acetyl CoA: aerobic oxidation
If significant amount of materials are removed from the citric acid cycle to produce amino acids for protein synthesis
Less ATP Less carbon diozde Four carbon comibies with acetyl CoA.
Which of the following statements describes NAD+?
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.
After completion of the citric acid cycle, most of the usable energy from the original glucose molecules is in the from of
NADH
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, drag it to the "not input or output" bin.
Net Input: ADP, NAD⁺, Glucose Net Output: ATP, NADH and Pyruvate, not input or output: O₂, CO₂, coenzyme A and acetyl CoA
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. Drag each compound to the appropriate bin. If a compound is not involved in the citric acid cycle, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of the citric acid cycle are included.)
Net Input: Acetyl CoA, NAD⁺, ADP Net Output: Coenzyme A, CO₂, NADH, ATP Not Input or Output: Pyruvate, Glucose, O₂
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. Drag each compound to the appropriate bin. If a compound is not involved in oxidative phosphorylation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of oxidative phosphorylation are listed.)
Net Input: NADH, ADP, O₂ Net Output: NAD⁺, ATP, CO₂ and Water Not Input or Output: Pyruvate, Glucose, Acetyl CoA, Coenzyme A and CO₂.
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. Drag each compound to the appropriate bin. If a compound is not involved in acetyl CoA formation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of acetyl CoA formation are included.)
Net Input: NAD⁺, coenzyme A, pyruvate Net Output: NADH, acetyl CoA, CO₂ not input or output: O₂, ADP, glucose and ATP
Fermentation is anaerobic metabolism of pyruvate The citric acid cycle uses pyruvate. Generate most NADH. The oxidation of pyruvate is yield acetyl CoA Chemiosmosis is electron transport make ATP.
None
10. Which of the following is a correct desperation of events of cellar respiration in proper sequence?
Oxidation of gluycose to pruvate, oxdiation of pruvate, citiric acid cycle, oxidative phosphorylation.
9.2- Glycolysis harvest chemical energy by oxidizing glucose to pyruvate.
Oxidation of three carbon sugar, glyceraldehyde 3-phospate, yield energy. Electrons and H ion transfeed to NAD plus forming NADH. Phosplate group attched to oxidzied substrate. ATP formed by substrate level phosphorlyation when phospate transferred to ADP.
9. Most of the ATP produced in cellular respiration comes from Oxidative phosphorylation Reduction of NADH Substrate level phosphorylation Glycolysis The citric acid cycle
Oxidative phoshorlation
What happen in citric acid cycle?
Pyruvate is oxized and carbon dioxide removed. The electrons removed to reudce NAD plus to NADH. 2 ATP, 6 NADH, 2 FADH
Energy from glycolysis Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?
Pyruvate, NADH, ATP ATP
anaerobic reduction of pyruvate during lactic acid fermentation.
Reactant: pyruvate, NADH Product: lactate, NAD plus
Most of the electron moved from glucose by cellular respiration are used for
Reduing NAD ion to NADH in glycolysis and citirc acid cycle, producing a proton gradient for ATP synthesis in the mitochondira.
Which is he events of pyruvate to acetyl CoA before citric acid cycle?
Relases of carbon dioxde and synthesis of NADH.
The effect of gramicidin on oxidative phosphorylation 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.
Remains the same: proton pumping rate, electron transport rate, rate of oxygen uptake Decreases (or goes to zero): Rate of ATP synthesis, size of the proton gradient
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.
Remains the same: proton pumping rate, electron transport rate, rate of oxygen uptake. Decreases(or goes to zero): rate of ATP synthesis, size of proton gradient Increases:N/A
Why no production of carbon dioxide in glycolysis?
Same number of carbons at the starting material.
9.6- Glycolysis and the citric acid cycle connect to many other metabolic pathways
The ATP produced by catabolic pathways is used to drive anabolic pathways. Also, many of the intermediates of glycolysis and the citric acid cycle are sued in the biosynthesis of a cell's molecules.
9.4-During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis.
The H through ATP synthase coomplex causes the rotor and attched rod to rotate, exposing catalytic sites in knob portion that producce ATP from ADP. ATP systhesis found in inner mitochoniral memebrance, plasma memberane of prokaryotes, memberances with chlorpolast.
In most cells, not all of the carbon compounds that participate in glycolysis and the citric acid cycle are converted to carbon dioxide by cellular respiration. What happens to the carbon in these compounds that does not end up as CO2?
The carbon compounds are removed from these processes to serve as building blocks for other complex molecules.
Which of the following statements about the chemiosmotic synthesis of ATP is correct?
The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane.
Where do the reactions of glycolysis occur in eukaryotic cell? The matrix of the mitochondria The inner membrane of mitochondria The cytosol Across inner membrane of the mitochondria
The cytosol
Energy for synthesizing ATP is obtained by ATP synthase directly from
The flow of H ion across the inner mitochondiral memebrance through ATP
In eukaryotic cell, the components of the electron transport chain are located at
The inner memebrane of the mitochiondion.
Which statement about the citric acid cycle is correct?
The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.
Where do the reactions of citric acid cycle occur in eukaryotic cells?
The mactrix of mitochonidon
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?
The pH of the matrix increases.
Which one of the following statements about the redox reactions of the electron transport chain is correct?
The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane.
11. What happens to the temperature and carbon dioxide concentration during a hour class period in classroom of 300 students if the heating and air condition is turned off and all doors are kept closed?
The temperture and the level of carbon dioxide rise as heat and carbon dioxde are by products of cellar respiration.
Why are carbohydrates and fats considered high energy foods?
They have a lot of electrons associated with hydrogen.
A small amount of ATP is made in glycolysis when
Transfer pf a phosphate rgoup from a fragment of gluose to ADP by substrate level phosphoraltion.
When energy give up electrons through the electron transport chain?
When pumping H ion across a memebrane.
Net redox reaction in acetyl CoA formation and the citric acid cycle In the sequential reactions of acetyl CoA formation and the citric acid cycle, pyruvate (the output from glycolysis) is completely oxidized, and the electrons produced from this oxidation are passed on to two types of electron acceptors. Drag the labels on the left to show the net redox reaction in acetyl CoA formation and the citric acid cycle. Note that two types of electron carriers are involved.
a) CO2 (b) NADH (c) FAD (d)FADH2
The coupled stages of cellular respiration The four stages of cellular respiration do not function independently. Instead, they are coupled together because one or more outputs from one stage functions as an input to another stage. The coupling works in both directions, as indicated by the arrows in the diagram below. In this activity, you will identify the compounds that couple the stages of cellular respiration. Drag the labels on the left onto the diagram to identify the compounds that couple each stage. Labels may be used once, more than once, or not at all.
a. pyruvate b. NADH c. NAD+ d. NADH e. NAD+
The oxygen consumed during cellular respiration is involved directly in which process or event?
accepting electrons at the end of the electron transport chain
Which of these enters the citric acid cycle?
acetyl CoA
Which of these is NOT a product of the citric acid cycle?
acetyl CoA
What is the purpose of beta oxidation in respiration?
breakdown of fatty acids
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?
catabolic pathways
Where does glycolysis take place in eukaryotic cells?
cytosol
Which metabolic pathway is common to both cellular respiration and fermentation?
glycolysis
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
glycolysis
Which of the following normally occurs regardless of whether or not oxygen (O2) is present?
glycolysis
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
glycolysis
A molecule that is phosphorylated
has an increased chemical potential energy; it is primed to do cellular work.
Where is ATP synthase located in the mitochondrion?
inner membrane
In muscle cell, fermentation produce
lactate and NAD plus
In muscle cells, fermentation produces _____.
lactate and NAD+
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction
loses electrons and loses potential energy.
Where are the proteins of the electron transport chain located?
mitochondrial inner membrane
Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?
mitochondrial intermembrane space
During cellular respiration, acetyl CoA accumulates in which location?
mitochondrial matrix
Glycolysis: If the compound is not involved in glycolysis, drag it to the "not input or output" bin
net input: ADP, NAD+, Glucose net output: ATP, NADH, Pyruvate not input or output: O2, CO2, acetyl CoA, Coenzyme A
Acetyl CoA: If a compound is not involved in acetyl CoA formation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of acetyl CoA formation are included.)
net input: NAD+, Coenzyme A, pyruvate net output: NADH, acetyl CoA, CO2 not input or output: ATP,ADP,glucose,O2
Oxidative phosphorylation: If a compound is not involved in oxidative phosphorylation, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of oxidative phosphorylation are listed.)
net input: NADH, ADP, O2 net output: NAD+, ATP, water not input or output: acetyl CoA, pyruvate, coenzyme A, glucose, CO2
Citric acid cycle: If a compound is not involved in the citric acid cycle, drag it to the "not input or output" bin. (Note that not all of the inputs and outputs of the citric acid cycle are included.)
net input: acetyl CoA, NAD+, ADP net output: ATP, NADH, Coenzyme A, CO2 not input or output: O2,Glucose, pyruvate
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?
oxidation of pyruvate to acetyl CoA and the citric acid cycle
Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?
oxidative phosphorylation (chemiosmosis)
One function of both alcohol fermentation and lactic acid fermentation is to
oxidize NADH to NAD+.
When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes
oxidized.
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is
oxygen.
In mitochondria, exergonic redox reactions
provide the energy that establishes the proton gradient.
What is the oxidizing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+
pyruvate
In fermentation _____ is reduced and _____ is oxidized.
pyruvate ... NADH
Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions? pyruvate, ATP, and NADH NADH only ATP only O2 only CO2 only ATP and NADH only pyruvate and ATP only
pyruvate, ATP, and NADH
Sort the following items according to whether they are reactants or products in the anaerobic reduction of pyruvate during lactic acid fermentation.
reactants: pyruvate, NADH Products: lactate, NAD+
In glycolysis, ATP molecules are produced by _____.
substrate-level phosphorylation
In the citric acid cycle, ATP molecules are produced by _____.
substrate-level phosphorylation
Most CO2 from catabolism is released during
the citric acid cycle.
What is proton-motive force?
the force provided by a transmembrane hydrogen ion gradient
In mitochondrial electron transport, what is the direct role of O2?
to function as the final electron acceptor in the electron transport chain
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?
two
In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?
two ATP
The electrons stripped from glucose in cellular respiration end up in which compound?
water
