CellBio Exam 2

PGA down, RuBP up

Carbon dioxide concentration is suddenly reduced 1000-fold. PGA down, RuBP up PGA up, RuBP down PGA up, RuBP unchanged PGA unchanged, RuBP up

2 C

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. At a:

coenzyme A, nucleotide phosphorylation, malate dehydrogenase, conversion of lactate into pyruvate

Which molecules and/or functions (in a prokaryotic cell) would you find in the Cytoplasm: (4)

accumulation of a high proton concentration

Which molecules and/or functions (in a prokaryotic cell) would you find in the Exterior of the Cell: (1)

6

How many molecules of oxygen will move per molecule of glucose catabolized?

2

How many molecules of pyruvate will move per molecule of glucose catabolized?

42

How many molecules of water will move per molecule of glucose catabolized?

2

How many pairs of electrons will move per molecule of glucose catabolized?

coenzyme Q, succinate dehydrogenase, fatty acid elongation, ATP synthase, respirasomes

Which molecules and/or functions (in a prokaryotic cell) would you find in the Plasma Membrane: (5)

Fermentation

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell? Krebs cycle Electron transport chain Fermentation Glycolysis

Electron transport and chemiosmosis

Which stage of glucose metabolism produces the most ATP? Krebs cycle Glycolysis Electron transport and chemiosmosis Fermentation of pyruvate to lactate

Glycolysis

Which step of the cellular respiration pathway can take place in the absence of oxygen? Krebs cycle Glycolysis Fermentation Electron transport chain

Glycolysis, Acetyl CoA formation, Krebs cycle (Citric acid cycle), Oxidative phosphorylation (electron transport and chemiosmotic ATP synthesis)

4 stages of cellular respiration

PGA up, RuBP down

An inhibitor of photosystem II is added. PGA down, RuBP up PGA up, RuBP down PGA up, RuBP unchanged PGA unchanged, RuBP up

2

Based on what you already know about the ETS, how many moles of ATP would you expect to be formed per mole of β-hydroxybutyrate oxidized?

6 ATP 6 ADP

Drag the labels to the appropriate targets to indicate the numbers of molecules of ATP/ADP, NADPH/NADP+, and Pi (inorganic phosphate groups) that are input to or output from the Calvin cycle. At a:

6 NADPH 6 NADP+

Drag the labels to the appropriate targets to indicate the numbers of molecules of ATP/ADP, NADPH/NADP+, and Pi (inorganic phosphate groups) that are input to or output from the Calvin cycle. at b

6 Pi

Drag the labels to the appropriate targets to indicate the numbers of molecules of ATP/ADP, NADPH/NADP+, and Pi (inorganic phosphate groups) that are input to or output from the Calvin cycle. at c

2 Pi

Drag the labels to the appropriate targets to indicate the numbers of molecules of ATP/ADP, NADPH/NADP+, and Pi (inorganic phosphate groups) that are input to or output from the Calvin cycle. at d

3 ADP 3 ATP

Drag the labels to the appropriate targets to indicate the numbers of molecules of ATP/ADP, NADPH/NADP+, and Pi (inorganic phosphate groups) that are input to or output from the Calvin cycle. at e

6 C

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. At b:

6 C

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. At c:

5 C

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. At d:

4 C

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. At e:

4 C

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. At f:

4 C

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. At g:

4 C

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. At h:

4 C

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. At i:

inner mitochondrial membrane

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. Match each stage of cellular respiration with the cellular location in which it occurs. Stage of cellular respiration: Oxidative phosphorylation Location?

mitochondrial matrix

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. Match each stage of cellular respiration with the cellular location in which it occurs. Stage of cellular respiration: acetyl CoA formation Location?

mitochondrial matrix

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. Match each stage of cellular respiration with the cellular location in which it occurs. Stage of cellular respiration: citric acid cycle Location?

cytosol

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. Match each stage of cellular respiration with the cellular location in which it occurs. Stage of cellular respiration: glycolysis Location?

NADH

Electron donor of Complex I

succinate

Electron donor of Complex II

coenzyme Q

Electron donor of Complex III:

cytochrome c

Electron donor of Complex IV

Electrons, Pyruvate, Oxygen, ADP

For aerobic respiration, a variety of substances must be in a state of flux across the inner mitochondrial membrane. Assuming a brain cell in which glucose is the sole energy source, indicate for each of the following substances whether you would expect a net flux across the membrane and, if so, in which direction. In (4):

Acetyl CoA, Glycerol-3-phosphate, NADH, FADH2, Oxaloacetate, Proton

For aerobic respiration, a variety of substances must be in a state of flux across the inner mitochondrial membrane. Assuming a brain cell in which glucose is the sole energy source, indicate for each of the following substances whether you would expect a net flux across the membrane and, if so, in which direction. No flux/ No net flux (6):

ATP, Water

For aerobic respiration, a variety of substances must be in a state of flux across the inner mitochondrial membrane. Assuming a brain cell in which glucose is the sole energy source, indicate for each of the following substances whether you would expect a net flux across the membrane and, if so, in which direction. Out (2):

3 molecules 3 carbons

For each intermediate compound in the Calvin cycle, identify the number of molecules of that intermediate and the total number of carbon atoms contained in those molecules. At a

6 molecules 18 carbons

For each intermediate compound in the Calvin cycle, identify the number of molecules of that intermediate and the total number of carbon atoms contained in those molecules. At b:

6 molecules 18 carbons

For each intermediate compound in the Calvin cycle, identify the number of molecules of that intermediate and the total number of carbon atoms contained in those molecules. At c:

5 molecules 15 carbons

For each intermediate compound in the Calvin cycle, identify the number of molecules of that intermediate and the total number of carbon atoms contained in those molecules. At d:

3 molecules 15 carbons

For each intermediate compound in the Calvin cycle, identify the number of molecules of that intermediate and the total number of carbon atoms contained in those molecules. At e:

3 molecules 15 carbons

For each intermediate compound in the Calvin cycle, identify the number of molecules of that intermediate and the total number of carbon atoms contained in those molecules. At f:

ADP, NAD+, glucose

From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of glycolysis. Net input: (3)

ATP, NADH, pyruvate

From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of glycolysis. Net output: (3)

Fluoroacetate is probably activated to fluoroacetyl CoACoA and condensed onto oxaloacetate by citrate synthase to generate fluorocitrate.

How could fluoroacetate be converted to fluorocitrate? Fluoroacetate is probably activated to fluoroacetyl CoACoA and condensed onto isocitrate by citrate synthase to generate fluorocitrate. Fluoroacetate is probably activated to fluoroacetyl CoACoA and condensed onto oxaloacetate by aconitase to generate fluorocitrate. Fluoroacetate is probably activated to fluoroacetyl CoACoA and condensed onto oxaloacetate by citrate synthase to generate fluorocitrate. Fluoroacetate is probably activated to fluoroacetyl CoACoA and condensed onto isocitrate by aconitase to generate fluorocitrate

36

How many molecules of ADP will move per molecule of glucose catabolized?

36

How many molecules of ATP will move per molecule of glucose catabolized?

Both electron transport and ATP synthesis would stop.

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.) Electron transport would be unaffected but ATP synthesis would stop. Electron transport would stop but ATP synthesis would be unaffected. Both electron transport and ATP synthesis would stop. Neither electron transport nor ATP synthesis would be affected.

The middle carbon atom of pyruvate in the TCA cycle becomes the carboxyl carbon of acetate and hence the newly added (upper) carboxyl group in citrate.

If pyruvate-2-14C14C (pyruvate with the middle carbon atom radioactively labeled) is provided to actively respiring mitochondria, most of the radioactivity will be incorporated into citrate. Trace the route whereby radioactively labeled carbon atoms are incorporated into citrate, and indicate where in the citrate molecule the label will first appear. The middle carbon atom of pyruvate in the TCA cycle becomes the carboxyl carbon of acetate and hence the newly added (upper) carboxyl group in citrate. The middle carbon atom of pyruvate in the TCA cycle becomes the carboxyl carbon of acetate and hence the newly added (middle) carbonyl group in citrate. The middle carbon atom of pyruvate in the TCA cycle becomes the carboxyl carbon of acetate and hence the newly added (upper) carbonyl group in citrate. The middle carbon atom of pyruvate in the TCA cycle becomes the carboxyl carbon of acetate and hence the newly added (middle) carboxyl group in citrate.

NAD+, coenzyme A, pyruvate

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. Net input: (3)

NADH, acetyl CoA, 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. Net output: (3)

all TCA intermediates, then carbon dioxide

In an experiment, mice were fed glucose containing a radioactive carbon atom at position 1. This atom was found in __________. all TCA intermediates, then carbon dioxide NADH early TCA intermediates only, then carbon dioxide coenzyme A

to function as the final electron acceptor in the electron transport chain

In mitochondrial electron transport, what is the direct role of O2? to provide the driving force for the synthesis of ATP from ADP and Pi to oxidize NADH and FADH2 from glycolysis, acetyl CoA formation, and the citric acid cycle to function as the final electron acceptor in the electron transport chain to provide the driving force for the production of a proton gradient

acetyl CoA, NAD+, ADP

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. Net input: (3)

coenzyme A, CO2, NADH, ATP

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. Net output: (4)

substrate-level phosphorylation

In the citric acid cycle, ATP molecules are produced by _____. oxidative phosphorylation photosynthesis substrate-level phosphorylation cellular respiration photophosphorylation

water

In the electron transport system, hydrogen atoms removed from NADH ultimately end up as part of __________. carbon dioxide water ATP NADH

NADH, ADP, 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. Net inputs: (3)

NAD+, ATP, water

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. Net outputs: (3)

H2O, O2

In the light reactions, light energy is used to oxidize ____ to ____

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.

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. More ATP is produced per CO2 released in cyclic processes than in linear processes. 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. Redox reactions that simultaneously produce CO2 and NADH occur only in cyclic processes. Cyclic processes, such as the citric acid cycle, require a different mechanism of ATP synthesis than linear processes, such as glycolysis.

CO2

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. show the net redox reaction in acetyl CoA formation and the citric acid cycle. (a) pyruvate is oxidized to:

NADH

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. show the net redox reaction in acetyl CoA formation and the citric acid cycle. (b) NAD+ is reduced to

FAD

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. show the net redox reaction in acetyl CoA formation and the citric acid cycle. (c) _____ is reduced to FADH2

FADH2

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. show the net redox reaction in acetyl CoA formation and the citric acid cycle. (d) FAD is reduced to ______

Carbon dioxide

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration? Carbon dioxide Water NADH ATP

no

Is energy input required for this step of election transport? 1. Water > P680+

yes

Is energy input required for this step of election transport? 2. P680 > Pq

no

Is energy input required for this step of election transport? 3. Pq> P700+

yes

Is energy input required for this step of election transport? 4. P700 > Fd

no

Is energy input required for this step of election transport? 5. Fd > NADP+

PGA up, RuBP down

Light is restricted to green wavelengths (510-550 nm) PGA down, RuBP up PGA up, RuBP down PGA up, RuBP unchanged PGA unchanged, RuBP up

limit movement of material between the intracristal and intermembrane spaces.

Mitochondrial crista junctions contain the mitochondrial DNA. connect thylakoid membranes. limit movement of material between the intracristal and intermembrane spaces. are associated with the movement of material from the cytosol into the intermembrane space. are large pores in the inner membrane.

Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.

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? There is more NADH than FADH2 made for every glucose that enters cellular respiration. 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. FADH2 is made only in the citric acid cycle while NADH is made in glycolysis, acetyl CoA formation, and the citric acid cycle. Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor. It takes more energy to make ATP from ADP and Pi using FADH2 than using NADH.

PGA up, RuBP unchanged

Oxygen concentration is reduced from 20% to 1%. PGA down, RuBP up PGA up, RuBP down PGA up, RuBP unchanged PGA unchanged, RuBP up

hibernating bear

Some adult mammals also have brown fat. Would you expect to find more brown fat tissue and more thermogenin in a hibernating bear or in a physically active bear?

NADH and FADH2 donate their electrons to the chain.

Which of the following statements about the electron transport chain is true? NADH and FADH2 donate their electrons to the chain. Electrons gain energy as they move down the chain. The electron transport chain is the first step in cellular respiration. Water is the last electron acceptor.

The rate of O2 production would decrease because the rate of ADP and NADP+ production by the Calvin cycle would decrease.

Suppose that the concentration of CO2 available for the Calvin cycle decreased by 50% (because the stomata closed to conserve water). Which statement correctly describes how O2 production would be affected? (Assume that the light intensity does not change.) The rate of O2 production would remain the same because the light intensity did not change. The rate of O2 production would decrease because the rate of G3P production by the Calvin cycle would decrease. The rate of O2 production would decrease because the rate of ADP and NADP+ production by the Calvin cycle would decrease. The rate of O2 production would remain the same because the light reactions are independent of the Calvin cycle.

6, 6, 22

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. ATP from oxidative phosphorylation

2, 0, 2

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. ATP from substrate-level phosphorylation

-, -, 2

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. ATP per FADH2

3, 3, 3

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. ATP per NADH

8, 6, 24

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. Max ATP yield

0, 2, 4

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. Yield of Co2

0, 0, 2

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. Yield of FADH2

2, 2, 6

Table below is intended as a means of summarizing the ATP yield during the aerobic oxidation of glucose. Complete the table for an aerobic bacterium. yield of NADH

NADPH, NADP+

The Calvin cycle oxidizes the light-reactions product _____ to _____

reduction of primary electron acceptor, light absorption

Which of the processes take place in Both Photosystem I and Photosystem II (2)

CO2, G3P

The electrons derived from this oxidation reaction in the Calvin cycle are used to reduce _____ to _____

NADP+, NADPH

The electrons derived from this oxidation reaction in the light reactions are used to reduce ____ to ___

pyruvate

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. What is at a?

NADH

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. What is at b?

NAD+

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. What is at c?

NADH

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. What is at d?

NAD+

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. What is at e?

FADH2 has a lower (less negative) redox potential than NADH does

The number of ATPs per NADH generated by the electron transport system is higher than the number generated per FADH2 because __________. FADH2 has a higher (more negative) redox potential than NADH does electrons from FADH2 are not oxidized all the way to water NADH is converted to NAD+, which increases the charge gradient for ATP synthesis FADH2 has a lower (less negative) redox potential than NADH does

reduction of NADP+, oxidation of electron transport chain between the two photosystems

Which of the processes take place in Photosystem I only (2)

oxidation of water, reduction of electron transport chain between the two photosystems

Which of the processes take place in Photosystem II only (2)

ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production.

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. ATP levels would rise at first, decreasing the inhibition of PFK and increasing the rate of ATP production. ATP levels would fall at first, increasing the inhibition of PFK and increasing the rate of ATP production. ATP levels would rise at first, increasing the inhibition of PFK and increasing the rate of ATP production.

acetyl CoA

Which of these enters the citric acid cycle? acetyl CoA pyruvate NADH + H+ glucose G3P

oxidized cytochrome c

To determine which segments of the electron transport system (ETS) are responsible for proton pumping and hence for ATPATP synthesis, investigators usually incubate isolated mitochondria under conditions such that only a portion of the ETS is functional. One approach is to supply the mitochondria with an electron donor and an electron acceptor that are known to tap into the ETS at specific points. In addition, inhibitors of known specificity are often added. In one such experiment, mitochondria were incubated with β-hydroxybutyrate, oxidized cytochrome c, ADP, Pi, and cyanide. (Mitochondria have an NAD+ dependent dehydrogenase that is capable of oxidizing β-hydroxybutyrate to β-ketobutyrate.) What is the electron acceptor? beta-hydroxybutyrate oxidized cytochrome c ADP cyanide

acetyl CoA

Which of these is NOT a product of the citric acid cycle? acetyl CoA FADH2 CO2 ATP NADH + H+

beta-hydroxybutyrate

To determine which segments of the electron transport system (ETS) are responsible for proton pumping and hence for ATPATP synthesis, investigators usually incubate isolated mitochondria under conditions such that only a portion of the ETS is functional. One approach is to supply the mitochondria with an electron donor and an electron acceptor that are known to tap into the ETS at specific points. In addition, inhibitors of known specificity are often added. In one such experiment, mitochondria were incubated with β-hydroxybutyrate, oxidized cytochrome c, ADP, Pi, and cyanide. (Mitochondria have an NAD+ dependent dehydrogenase that is capable of oxidizing β-hydroxybutyrate to β-ketobutyrate.) What is the electron donor in this system? beta-hydroxybutyrate oxidized cytochrome c ADP cyanide

True

True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups. T/F?

True

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria. T/F?

Glucose utilization would increase a lot.

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. Glucose utilization would increase a little. Glucose utilization would remain the same. Glucose utilization would decrease a little. Glucose utilization would decrease a lot.

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.

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? ATP is needed to convert pyruvate to acetyl CoA. Without oxygen, no ATP can be made in oxidative phosphorylation. 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. Oxygen is required to convert glucose to pyruvate in glycolysis. Without oxygen, no pyruvate can be made. Oxygen is an input to acetyl CoA formation.

Given that ATP synthesis does not occur, the energy is lost as heat. For a newborn baby, the heat generated this way may be critical to maintenance of body temperature.

What happens to the energy that is released as electron transport continues but ATP synthesis ceases? Why might it be advantageous for a baby to have thermogenin present in the inner membrane of the mitochondria that are present in brown fat tissue? Given that ATP synthesis does not occur, the energy is used for physical activity. For a newborn baby, the energy generated this way may be critical to skeletal muscle development. Given that ATP synthesis does not occur, the energy is used for cellular respiration. For a newborn baby, the energy generated this way may be critical to breathing. Given that ATP synthesis does not occur, the energy is lost as heat. For a newborn baby, the heat generated this way may be critical to maintenance of body temperature. Given that ATP synthesis does not occur, the energy is used for various types of chemical reactions. For a newborn baby, the energy generated this way may be critical to metabolic reactions.

38

What is the maximum ATP yield for an aerobic bacterium?

The most likely pathway of electron transport is from beta-hydroxybutyrate via NAD+, complex I, and complex III to cytochrome c.

What is the most likely pathway of electron transport in this system? The most likely pathway of electron transport is from β-hydroxybutyrate via NAD+, complex I, and complex IV to cytochrome c. The most likely pathway of electron transport is from cytochrome c via NAD+, complex I, and complex III to β-hydroxybutyrate. The most likely pathway of electron transport is from β-hydroxybutyrate via NAD+, complex I, and complex III to cytochrome c. The most likely pathway of electron transport is from cytochrome c via NAD+, complex I, and complex IV to β-hydroxybutyrate.

All of the energy that would normally have gone into ATP synthesis would be liberated as heat so that mammals would be overheated. The mitochondria would not be able to produce much ATP. The organism would therefore have to depend on glycolysis for its ATP synthesis, which would almost certainly not be adequate for an organism.

What would happen to a mammal if all of its mitochondria were equipped with uncoupling protein, rather than just those in brown fat tissue? Select the two correct statements. The mitochondria would not be able to produce much ATP. The organism would therefore have no sources for ATP synthesis, that would lead to mammal death. All of the energy that would normally have gone into ATP synthesis would be liberated as heat so that mammals would be overheated. The mitochondria would not be able to produce much ATP. The organism would therefore have to depend on glycolysis for its ATP synthesis, which would almost certainly not be adequate for an organism. All of the energy that would normally have gone into ATP synthesis would be liberated as heat so that mammals would be supercooled. The mitochondria would not be able to produce much ATP. The organism would therefore have to depend on the TCA cycle for its ATP synthesis, which would almost certainly not be adequate for an organism.

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.) decreases (or goes to zero): (2)

proton pumping rate, electron transport rate, rate of oxygen uptake

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.) remains the same: (3)

matrix of mitochondria

Where does Beta oxidation occur in the cell? Porins outer membrane of mitochondria golgi complex nucleolus inner membrane of mitochondria extracellular space cytoplasm intermembrane space of mitochondria matrix of mitochondria

matrix of mitochondria

Where does citric acid cycle occur in the cell? Porins outer membrane of mitochondria golgi complex nucleolus inner membrane of mitochondria extracellular space cytoplasm intermembrane space of mitochondria matrix of mitochondria

inner membrane of mitochondria

Where does electron transport occur in the cell? Porins outer membrane of mitochondria golgi complex nucleolus inner membrane of mitochondria extracellular space cytoplasm intermembrane space of mitochondria matrix of mitochondria

cytoplasm

Where does glycolysis occur in the cell? Porins outer membrane of mitochondria golgi complex nucleolus inner membrane of mitochondria extracellular space cytoplasm intermembrane space of mitochondria matrix of mitochondria

outer membrane of mitochondria

Where does phyospholipid synthesis occur in the cell? Porins outer membrane of mitochondria golgi complex nucleolus inner membrane of mitochondria extracellular space cytoplasm intermembrane space of mitochondria matrix of mitochondria

aconitase

Which enzyme in the TCA cycle do you suspect is affected by fluorocitrate? aconitase fumarate hydratase citrate synthase succinate dehydrogenase isocitrate dehydrogenase malate dehydrogenase succinyl CoACoA synthetase αα-ketoglutarate dehydrogenase

Glucose

Which molecule is metabolized in a cell to produce energy for performing work? Phosphate ATP ADP Glucose

crista junctions, fatty acyl CoA translocase, dicarboxylate carrier

Which molecules and/or functions (in a prokaryotic cell) are not present at all:

The ingested compound is itself not toxic, but it is converted into a lethal metabolite in vivo.

Why is this phenomenon referred to as lethal synthesis? The ingested compound disrupts intermolecular bonds between TCA intermediates. The ingested compound is itself not toxic, but it is converted into a lethal metabolite in vivo. The ingested compound is itself not toxic, but it catalyzes the formation of lethal metabolites. The ingested compound forms covalent bonds with TCA intermediates and enzymes, inactivating them.

Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a buildup of at least one of the TCA cycle intermediates.

Why might you expect fluorocitrate to have an inhibitory effect on one or more of the TCA cycle enzymes if incubated with the purified enzymes in vitro, even though fluoroacetate has no effect? Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a reduction of at least one of the TCA cycle intermediates. Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a buildup of at least one of the TCA cycle intermediates. Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a conversion of at least one of the TCA cycle intermediates into inactive form. Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is an oxidation of at least one of the TCA cycle intermediates.