Ch. 7: Cellular Respiration

What would happen to the muscle cell's rate of glucose utilization under anaerobic conditions relative to aerobic conditions? 1. Glucose utilization would increase a lot. 2. Glucose utilization would increase a little. 3. Glucose utilization would remain the same. 4. Glucose utilization would decrease a little. 5. Glucose utilization would decrease a lot.

1. Glucose utilization would increase a lot. ATP made during fermentation comes from glycolysis, which produces a net of only 2 ATP per glucose molecule. In contrast, aerobic cellular respiration produces about 36 ATP per glucose molecule. To meet the same ATP demand under anaerobic conditions as under aerobic conditions, a cell's rate of glycolysis and glucose utilization must increase nearly 20-fold.

In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs? 1. Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH. 2. Pyruvate is reduced and decarboxylated, and the resulting electrons oxidize an NAD+ to an NADH 3. Pyruvate is oxidized and decarboxylated, and the resulting electrons are donated to NADH to produce NAD+. 4. 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. 5. Pyruvate is ionized directly to acetyl-coA.

1. Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH.

When protein molecules are used as fuel for cellular respiration, _____ are produced as waste. 1. amino groups 2. fatty acids 3. sugar molecules 4. molecules of lactate 5. ethanol and CO2

1. amino groups

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 _____. 1. carbon dioxide 2. NADH 3. water 4. ATP 5. oxygen gas

1. carbon dioxide

Location of: 1. glycolysis 2. acetyl CoA formation 3. citric acid cycle 4. oxidative phosphorylation

1. cytosol 2. mitochondrial matrix 3. mitochondrial matrix 4. inner mitochondrial membrane

monosaccharide, disaccharide, polysaccharide, carbohydrate 1. Lactose, the sugar in milk, is a ___, because it can be split into two monosaccharides. 2. A ___ cannot by hydrolyzed any further. 3. A carbohydrate that yields many monosaccharides when hydrolyzed is a ___. 4. A simple sugar is composed of equal parts carbon and water, which gave rise to the general name of any sugar as a ___.

1. disaccharide 2. monosaccharide 3. polysaccharide 4. carbohydrate

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? 1. glycolysis 2. synthesis of acetyl CoA from pyruvate 3. the citric acid cycle 4. the electron transport chain 5. reduction of pyruvate to lactate

1. glycolysis

Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration? 1. oxidation of glucose to pyruvate; reduction of pyruvate; citric acid cycle; oxidative phosphorylation 2. glycolysis; reduction of pyruvate; citric acid cycle; oxidative phosphorylation 3. oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation 4. glycolysis; oxidative phosphorylation; citric acid cycle; oxidation of pyruvate. 5. oxidation of pyruvate; citric acid cycle; oxidation of glucose to pyruvate; oxidative phosphorylation

1. oxidation of glucose to pyruvate; reduction of pyruvate; citric acid cycle; oxidative phosphorylation

NAD+, NADH, oxidized, glucose, reduced, pyruvate 1. When a compound donates (loses) electrons, that compound becomes ___. Such a compound is often referred to as an electron donor. 2. When a compound accepts (gains) electrons, that compound becomes ___. Such a compound is often referred to as an electron acceptor. 3. In glycolysis, the carbon-containing compound that functions as the electron donor is ___. 4. Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called ___. 5. ___ is the compound that unctions as the electron acceptor in glycolysis. 6. The reduced form of the electron acceptor in glycolysis is ___.

1. oxidized 2. reduced 3. glucose 4. pyruvate 5. NAD+ 6. NADH

During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction? 1. oxygen 2. glucose 3. carbon dioxide 4. water 5. both glucose and carbon dioxide

1. oxygen

In mitochondria, exergonic redox reactions __________. 1. provide the energy that establishes the proton gradient 2. use ATP to pump H+ out of the mitochondrion 3. are directly coupled to substrate-level phosphorylation 4. are the source of energy driving prokaryotic ATP synthesis 5. reduce carbon atoms to carbon dioxide

1. provide the energy that establishes the proton gradient

Where do the reactions of glycolysis occur in a eukaryotic cell? 1. the cytosol 2. the matrix of the mitochondrion 3. the inner membrane of the mitochondrion 4. in the intermembrane space of the mitochondrion 5. across the inner membrane of the mitochondrion

1. the cytosol

In mitochondrial electron transport, what is the direct role of O2? 1. to function as the final electron acceptor in the electron transport chain 2. to provide the driving force for the synthesis of ATP from ADP and Pi 3. to oxidize NADH and FADH2 from glycolysis, acetyl CoA formation, and the citric acid cycle 4. to provide the driving force for the production of a proton gradient

1. to function as the final electron acceptor in the electron transport chain The only place that O2 participates in cellular respiration is at the end of the electron transport chain, as the final electron acceptor. Oxygen's high affinity for electrons ensures its success in this role. Its contributions to driving electron transport, forming a proton gradient, and synthesizing ATP are all indirect effects of its role as the terminal electron acceptor.

A small amount of ATP is made in glycolysis by which of the following processes? 1. transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation 2. harnessing energy from the sun 3. transport of electrons through a series of carriers 4. transfer of electrons and hydrogen atoms to NAD+ 5. attachment of a free inorganic phosphate (Pi) group to ADP to make ATP

1. transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation

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? 1. two ATP, six NADH, two FADH2 2. four ATP, six NADH, two FADH2 3. three ATP, three NADH, one FADH2 4. about 38 ATP 5. one ATP, three NADH, one FADH2

1. two ATP, six NADH, two FADH2

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? 1. Fats are produced when cells take in more food than they need. 2. Fats are better electron donors to oxygen than are sugars. 3. Fats are less soluble in water than sugars. 4. Fats do not form true macromolecules as sugars do. 5. Fats are closely related to lipid molecules, the basic building blocks of cellular membranes.

2. Fats are better electron donors to oxygen than are sugars.

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? 1. It is stored as fat. 2. It is converted to heat. 3. It is used to make water from hydrogen ions and oxygen. 4. It is released as carbon dioxide and water 5. It is converted to starch.

2. It is converted to heat.

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? 1. ATP 2. lactate 3. carbon dioxide 4. ADP 5. oxygen

2. lactate

Most of the ATP produced in cellular respiration comes from which of the following processes? 1. glycolysis 2. oxidative phosphorylation 3. reduction of NADH 4. substrate-level phosphorylation 5. the citric acid cycle

2. oxidative phosphorylation

Which of the following accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle? 1. formation of CO2 and synthesis of ATP 2. release of CO2 and synthesis of NADH 3. release of CO2 and release of coenzyme A 4. removal of coenzyme A 5. regeneration of NAD+

2. release of CO2 and synthesis of NADH

The ATP synthase in a human cell obtains energy for synthesizing ATP directly from which of the following processes? 1. the oxidation of NADH and FADH2 2. the flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme 3. the oxidation of glucose 4. the movement of electrons through a series of carriers 5. the reduction of oxygen

2. 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? 1. the cytosol 2. the matrix of the mitochondrion 3. the cristae of the mitochondrion 4. the intermembrane space of the mitochondrion 5. across the inner membrane of the mitochondrion

2. the matrix of the mitochondrion

The overall efficiency of respiration (the percentage of the energy released that is saved in ATP) is approximately _____. 1. 0.5% 2. 2% 3. 35% 4. 94% 5. 100%

3. 35%

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? 1. ATP is needed to convert pyruvate to acetyl CoA. Without oxygen, no ATP can be made in oxidative phosphorylation. 2. Oxygen is an input to acetyl CoA formation. 3. 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. 4. Oxygen is required to convert glucose to pyruvate in glycolysis. Without oxygen, no pyruvate can be made.

3. 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. NAD+ couples oxidative phosphorylation to acetyl CoA formation. The NAD+ needed to oxidize pyruvate to acetyl CoA is produced during electron transport. Without O2, electron transport stops, and the oxidation of pyruvate to acetyl CoA also stops because of the lack of NAD+.

In glycolysis in the absence of oxygen, cells need a way to regenerate which compound? 1. ethanol 2. carbon dioxide 3. NAD+ 4. lactate 5. glucose

3. NAD+

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? 1. A high level of NADH is present in the cell. 2. The uptake of oxygen stops because electron transport was inhibited. 3. NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue. 4. Electrons are no longer available from the electron transport chain to power glycolysis and the citric acid cycle. 5. They run out of ADP.

3. NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue.

After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of _____. 1. acetyl CoA 2. ATP 3. NADH 4. CO2 5. FADH2

3. NADH

Why is the citric acid cycle called a cycle? 1. The acetyl CoA that enters the cycle is regenerated in the last step of the pathway. 2. NAD+ and FAD are recycled. 3. 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. 4. All of the carbon from glucose is cycled back into the atmosphere as carbon dioxide. 5. NADH is cycled down the electron transport chain.

3. 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 statement about the citric acid cycle is correct? 1. The oxidation of compounds by the citric acid cycle requires molecular oxygen. 2. The citric acid cycle depends on the availability of NAD+, which is a product of glycolysis. 3. The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle. 4. The citric acid cycle oxidizes glucose to carbon dioxide. 5. The citric acid cycle produces most of the ATP that is subsequently used by the electron transport chain.

3. The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.

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? 1. There are no oxidation or reduction reactions in glycolysis to produce CO2. 2. There is very little ATP produced in glycolysis. 3. The products of glycolysis contain the same total number of carbon atoms as in the starting material. 4. The initial steps of glycolysis require an input of energy in the form of ATP (two per glucose). 5. Glucose contains more carbons than the number of carbons found in the pyruvate products that are produced by glycolysis.

3. The products of glycolysis contain the same total number of carbon atoms as in the starting material.

Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step _____. 1. removes poisonous oxygen from the environment 2. extracts a bit more energy from glucose 3. enables the cell to recycle the reduced NADH to oxidized NAD+ 4. prevents pyruvate from accumulating 5. enables the cell to make pyruvate into substances it can use

3. enables the cell to recycle the reduced NADH to oxidized NAD+

The function of cellular respiration is to _____. 1. reduce CO2 2. extract CO2 from the atmosphere 3. extract usable energy from glucose 4. synthesize macromolecules from monomers 5. produce carbohydrates

3. extract usable energy from glucose

Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle? 1. formation of CO2 2. formation of ATP 3. formation of NADH and FADH2 4. utilization of O2 5. completion of substrate-level phosphorylation

3. 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? 1. two 2. three 3. four 4. about 16 ATP 5. about 32 ATP

3. four

In the overall process of glycolysis and cellular respiration, _____ is oxidized and _____ is reduced. 1. oxygen ... ATP 2. ATP ... oxygen 3. glucose ... oxygen 4. carbon dioxide ... water 5. glucose ... ATP

3. 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 _____. 1. bacteria are prokaryotes; they usually don't need to perform glycolysis 2. glycolysis produces so little ATP that the drug will have little effect 3. human cells must also perform glycolysis; the drug might also poison them 4. this step in the pathway of glycolysis can be skipped in bacteria, but not in humans 5. glycolysis can occur without the action of enzymes

3. human cells must also perform glycolysis; the drug might also poison them

During respiration in eukaryotic cells, the electron transport chain is located in or on the _____. 1. cytosol 2. matrix of the mitochondrion 3. inner membrane of the mitochondrion 4. intermembrane space of the mitochondrion 5. None of the listed responses is correct.

3. inner membrane of the mitochondrion

glucose + glucose —> _____ by _____. 1. lactose + water ... hydrolysis 2. sucrose + water ... dehydration synthesis 3. maltose + water ... dehydration synthesis 4. cellulose + water ... hydrolysis 5. starch + water ... dehydration synthesis

3. maltose + water ... dehydration synthesis Maltose is the disaccharide formed when two glucose molecules are linked by dehydration synthesis.

The energy given up by electrons as they move through the electron transport chain is used in which of the following processes? 1. the breakdown of glucose 2. the production of NADH and FADH2 3. pumping H+ across a membrane 4. the oxidation of water 5. the production of CO2

3. pumping H+ across a membrane

The electrons stripped from glucose in cellular respiration end up in which compound? 1. oxygen 2. carbon dioxide 3. water 4. ATP 5. NADH

3. water At the end of the electron transport chain, the electrons and hydrogen atoms are added to oxygen, forming water.

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? 1. ATP levels would rise at first, increasing the inhibition of PFK and increasing the rate of ATP production. 2. ATP levels would rise at first, decreasing the inhibition of PFK and increasing the rate of ATP production. 3. ATP levels would fall at first, increasing the inhibition of PFK and increasing the rate of ATP production. 4. ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production.

4. ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production. An increased demand for ATP by a cell will cause an initial decrease in the level of cellular ATP. Lower ATP decreases the inhibition of the PFK enzyme, thus increasing the rate of glycolysis, cellular respiration, and ATP production. It is the initial decrease in ATP levels that leads to an increase in ATP production.

How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? 1. Electron transport would be unaffected but ATP synthesis would stop. 2. Electron transport would stop but ATP synthesis would be unaffected. 3. Neither electron transport nor ATP synthesis would be affected. 4. Both electron transport and ATP synthesis would stop.

4. Both electron transport and ATP synthesis would stop. Oxygen plays an essential role in cellular respiration because it is the final electron acceptor for the entire process. Without O2, mitochondria are unable to oxidize the NADH and FADH2 produced in the first three steps of cellular respiration, and thus cannot make any ATP via oxidative phosphorylation. In addition, without O2 the mitochondria cannot oxidize the NADH and FADH2 back to NAD+ and FAD, which are needed as inputs to the first three stages of cellular respiration.

Which of the following best describes the electron transport chain? 1. Electrons are pumped across a membrane by active transport. 2. Acetyl CoA is fully oxidized to CO2. 3. Hydrogen atoms are added to CO2 to make an energy-rich compound. 4. Electrons are passed from one carrier to another, releasing a little energy at each step. 5. Glucose is broken down to a three-carbon compound in preparation for the citric acid cycle.

4. Electrons are passed from one carrier to another, releasing a little energy at each step.

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? 1. 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. 2. 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. 3. 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. 4. Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration. 5. 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.

4. Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.

Most of the electrons removed from glucose by cellular respiration are used for which of the following processes? 1. reducing NAD+ to NADH in glycolysis and the citric acid cycle 2. producing a proton gradient for ATP synthesis in the mitochondria 3. driving substrate-level phosphorylation in glycolysis 4. The first two choices are correct. 5. The second and third answers are correct.

4. The first two choices are correct.

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? 1. The cytochromes phosphorylate ADP to form ATP. 2. NAD+ is oxidized. 3. ATP synthase pumps protons by active transport. 4. The pH of the matrix increases. 5. The electrons gain free energy.

4. The pH of the matrix increases.

Which of these is a polysaccharide? 1. sucrose 2. lactose 3. galactose 4. cellulose 5. glucose

4. cellulose

Of the following molecules in the glycolytic pathway (the process of glycolysis), the one with the most chemical energy is _____. 1. pyruvate 2. glucose 3. fructose-6-phosphate 4. fructose-1,6-bisphosphate 5. glyceraldehyde-3-phosphate

4. fructose-1,6-bisphosphate

Of the metabolic pathways listed below, which is the only pathway found in all organisms? 1. cellular respiration 2. the citric acid cycle 3. the electron transport chain 4. glycolysis 5. fermentation

4. glycolysis

Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that _____. 1. oxygen is so abundant in the atmosphere 2. oxygen gas is composed of two atoms of oxygen 3. oxygen gas contains a double bond 4. the oxygen atom is very electronegative 5. oxygen acts as the final electron acceptor in cellular respiration

4. the oxygen atom is very electronegative

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? 1. There is more NADH than FADH2 made for every glucose that enters cellular respiration. 2. It takes more energy to make ATP from ADP and Pi using FADH2 than using NADH. 3. 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. 4. FADH2 is made only in the citric acid cycle while NADH is made in glycolysis, acetyl CoA formation, and the citric acid cycle. 5. Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.

5. Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor. Electrons derived from the oxidation of FADH2 enter the electron transport chain at Complex II, farther down the chain than electrons from NADH (which enter at Complex I). This results in fewer H+ ions being pumped across the membrane for FADH2 compared to NADH, as this diagram shows. Thus, more ATP can be produced per NADH than FADH2.

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? 1. It was lost as heat. 2. It is stored in the ATP that was formed by glycolysis and the citric acid cycle. 3. It is stored in the carbon dioxide and water molecules released by these processes. 4. It is stored in pyruvate. 5. It is stored in NADH and FADH2

5. It is stored in NADH and FADH2 The electrons obtained from the oxidation of glucose are temporarily stored in NADH and FADH2. The energy derived from the oxidation of NADH and FADH2 is used to drive the electron transport chain and chemiosmotic synthesis of ATP.

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? 1. glycolysis 2. electron transport 3. ATP synthesis 4. All of the listed responses are correct. 5. None of the listed responses is correct.

5. 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? 1. chemiosmosis 2. fermentation 3. the oxidation of pyruvate 4. the citric acid cycle 5. None of the listed responses is correct.

5. 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? 1. The muscle cells will have more trouble making enough ATP to meet their energy requirements. 2. The cells will not be able to carry out oxidative phosphorylation. 3. The cells will consume glucose at an increased rate. 4. Only the first two answers are correct. 5. The first three answers are correct.

5. 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? 1. Less ATP will be produced by the cell. 2. Less CO2 will be produced by the cell. 3. The four-carbon compound that combines with acetyl CoA will have to be made by some other process. 4. The first two answers are correct. 5. The first three answers are correct.

5. The first three answers are correct.

Which of the following substances is/are involved in oxidative phosphorylation? 1. ADP 2. oxygen 3. ATP 4. None of the listed responses is correct. 5. The first three listed responses are involved in oxidative phosphorylation.

5. The first three listed responses are involved in oxidative phosphorylation.

Glycogen is _____. 1. the form in which plants store sugars 2. a source of saturated fat 3. a transport protein that carries oxygen 4. a polysaccharide found in plant cell walls 5. a polysaccharide found in animals

5. a polysaccharide found in animals Animals store energy in the form of glycogen.

During aerobic respiration, molecular oxygen (O2) is used for which of the following purposes? 1. at the end of glycolysis to oxidize pyruvate 2. at the end of the citric acid cycle to regenerate citric acid 3. between glycolysis and the citric acid cycle to split a carbon from pyruvate, producing CO2 4. as a source of O2 in every reaction that produces CO2 5. at the end of the electron transport chain to accept electrons and form H2O

5. at the end of the electron transport chain to accept electrons and form H2O

Which of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria? 1. ATP 2. an ATP-dependent proton pump 3. the production of NADH 4. the components of the electron transport chain 5. electrons moving down the electron transport chain

5. electrons moving down the electron transport chain

A molecule becomes more oxidized when it _____. 1. changes shape 2. gains a hydrogen (H+) ion 3. loses a hydrogen (H+) ion 4. gains an electron 5. loses an electron

5. loses an electron

Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions? 1. NADH only 2. CO2 only 3. ATP and NADH only 4. ATP only 5. pyruvate, ATP, and NADH 6. O2 only 7. pyruvate and ATP only

5. pyruvate, ATP, and NADH ATP is the main product of cellular respiration that contains energy that can be used by other cellular processes. Some ATP is made in glycolysis. In addition, the NADH and pyruvate produced in glycolysis are used in subsequent steps of cellular respiration to make even more ATP.

Muscle tissues make lactate from pyruvate to do which of the following? 1. speed up the rate of glycolysis 2. get rid of pyruvate produced by glycolysis 3. utilize the energy in pyruvate 4. produce additional CO2 5. regenerate NAD+

5. regenerate NAD+

Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes? 1. oxidative phosphorylation 2. substrate-level phosphorylation 3. glycolysis 4. anabolic pathways 5. the citric acid cycle

5. the citric acid cycle

Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O2) and produces CO2? 1. glycolysis 2. the citric acid cycle 3. the electron transport chain 4. the combination of glycolysis and the citric acid cycle 5. the combination of the citric acid cycle and electron transport

5. the combination of the citric acid cycle and electron transport