Chapter 9 Cellular Respiration

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?

Glycolysis

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the:

H+ concentration across the membrane holding ATP synthase.

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+ S Lactate + NAD+

Pyruvate

Most CO2 from catabolism is released during...

The citric acid cycle

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

The pH of the matrix increases.

Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 32 ATP from one glucose molecule. What happens to the rest of the energy in glucose? () a. It is converted to heat. b. It is released as carbon dioxide and water c. It is stored as fat. d. It is converted to starch. e. It is used to make water from hydrogen ions and oxygen.

a. It is converted to heat.

In glycolysis, there is no production of carbon dioxide as a product of the pathway. Which of the following is the best explanation for this? () a. The products of glycolysis contain the same total number of carbon atoms as in the starting material. b. There is very little ATP produced in glycolysis. c. There are no oxidation or reduction reactions in glycolysis to produce CO2. d. The initial steps of glycolysis require an input of energy in the form of ATP (two per glucose). e. Glucose contains more carbons than the number of carbons found in the pyruvate products that are produced by glycolysis.

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

The function of cellular respiration is to _____. () a. extract usable energy from glucose b. produce carbohydrates c. synthesize macromolecules from monomers d. extract CO2 from the atmosphere e. reduce CO2

a. extract usable energy from glucose

How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen? a. four b. three c. two d. about 16 ATP e. about 32 ATP

a. four

A molecule becomes more oxidized when it _____. () a. loses an electron b. loses a hydrogen (H+) ion c. gains a hydrogen (H+) ion d. changes shape e. gains an electron

a. loses an electron

During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction? a. oxygen b. carbon dioxide c. glucose d. water e. both glucose and carbon dioxide

a. oxygen

Where do the reactions of glycolysis occur in a eukaryotic cell? () a. the cytosol b. the inner membrane of the mitochondrion c. across the inner membrane of the mitochondrion d. in the intermembrane space of the mitochondrion e. the matrix of the mitochondrion

a. the cytosol

After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of _____. () a. acetyl CoA b. NADH c. CO2 d. FADH2 e. ATP

b. NADH

Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle? () a. utilization of O2 b. formation of NADH and FADH2 c. formation of CO2 d. formation of ATP e. completion of substrate-level phosphorylation

b. formation of NADH and FADH2

A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to kill bacteria in people with infections. However, he cannot do this because _____. () a. glycolysis can occur without the action of enzymes b. human cells must also perform glycolysis; the drug might also poison them c. bacteria are prokaryotes; they usually don't need to perform glycolysis d. glycolysis produces so little ATP that the drug will have little effect e. this step in the pathway of glycolysis can be skipped in bacteria, but not in humans

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

Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration? () a. glycolysis; reduction of pyruvate; citric acid cycle; oxidative phosphorylation b. oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation c. oxidation of glucose to pyruvate; reduction of pyruvate; citric acid cycle; oxidative phosphorylation d. glycolysis; oxidative phosphorylation; citric acid cycle; oxidation of pyruvate. e. oxidation of pyruvate; citric acid cycle; oxidation of glucose to pyruvate; oxidative phosphorylation

b. oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation

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

b. the oxygen atom is very electronegative

In the citric acid cycle, for each pyruvate that enters the cycle, one ATP, three NADH, and one FADH2 are produced. For each glucose molecule that enters glycolysis, how many ATP, NADH, and FADH2 are produced in the citric acid cycle? () a. four ATP, six NADH, two FADH2 b. two ATP, six NADH, two FADH2 c. about 38 ATP d. three ATP, three NADH, one FADH2 e. one ATP, three NADH, one FADH2

b. two ATP, six NADH, two FADH2

When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle also eventually stop working. Which of the following is the best explanation for this? () a. The uptake of oxygen stops because electron transport was inhibited. b. A high level of NADH is present in the cell. c. NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue. d. Electrons are no longer available from the electron transport chain to power glycolysis and the citric acid cycle. e. They run out of ADP.

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

In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs? () a. Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH. b. Pyruvate is reduced and decarboxylated, and the resulting electrons oxidize an NAD+ to an NADH c. Pyruvate is oxidized and decarboxylated, and the resulting electrons are donated to NADH to produce NAD+. d. Pyruvate is reduced to acetyl-coA, which involves the reduction of pyruvate, the addition of a carbon dioxide from the environment, and its reduction by NADH. e. Pyruvate is ionized directly to acetyl-coA.

c. Pyruvate is oxidized and decarboxylated, and the resulting electrons are donated to NADH to produce NAD+.

Why is the citric acid cycle called a cycle? () a. The acetyl CoA that enters the cycle is regenerated in the last step of the pathway. b. NADH is cycled down the electron transport chain. c. 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. d. All of the carbon from glucose is cycled back into the atmosphere as carbon dioxide. e. NAD+ and FAD are recycled.

c. 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.

In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in _____. () a. NADH b. oxygen gas c. carbon dioxide d. ATP e. water

c. carbon dioxide

The ATP synthase in a human cell obtains energy for synthesizing ATP directly from which of the following processes? () a. the oxidation of NADH and FADH2 b. the reduction of oxygen c. the flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme d. the oxidation of glucose e. the movement of electrons through a series of carriers

c. the flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme

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

d. The first two choices are correct.

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

d. 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? a. ATP b. an ATP-dependent proton pump c. the components of the electron transport chain d. electrons moving down the electron transport chain e. the production of NADH

d. electrons moving down the electron transport chain

In the overall process of glycolysis and cellular respiration, _____ is oxidized and _____ is reduced. () a. glucose ... ATP b. oxygen ... ATP c. ATP ... oxygen d. glucose ... oxygen e. carbon dioxide ... water

d. glucose ... oxygen

Most of the ATP produced in cellular respiration comes from which of the following processes? () a. the citric acid cycle b. glycolysis c. substrate-level phosphorylation d. oxidative phosphorylation e. reduction of NADH

d. oxidative phosphorylation

Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes? () a. glycolysis b. substrate-level phosphorylation c. anabolic pathways d. the citric acid cycle e. oxidative phosphorylation

d. the citric acid cycle

Where do the reactions of the citric acid cycle occur in eukaryotic cells? () a. the intermembrane space of the mitochondrion b. across the inner membrane of the mitochondrion c. the cytosol d. the matrix of the mitochondrion e. the cristae of the mitochondrion

d. the matrix of the mitochondrion

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

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

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

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

If a compound that allows protons to freely diffuse across membranes is added to cells that are actively metabolizing glucose via cellular respiration, which of the following processes would stop? () a. glycolysis c. ATP synthesis d. All of the listed responses are correct. e. None of the listed responses is correct.

e. None of the listed responses is correct.

Which process is the one in which glucose is oxidized to generate two molecules of pyruvate, and in which ATP and NADH are produced? () a. the oxidation of pyruvate b. chemiosmosis c. the citric acid cycle d. fermentation e. None of the listed responses is correct.

e. None of the listed responses is correct.

Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a one-hour class period in a classroom of 300 students if the heating and air conditioning is turned off and all doors are kept closed? () a. Temperature goes 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. b. 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. c. 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. d. 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. e. Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.

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

Which of the following substances is/are involved in oxidative phosphorylation? () a. ADP b. oxygen c. ATP d. None of the listed responses is correct. e. The first three listed responses are involved in oxidative phosphorylation.

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

Of the following molecules in the glycolytic pathway (the process of glycolysis), the one with the most chemical energy is _____. () a. glyceraldehyde-3-phosphate b. fructose-6-phosphate c. pyruvate d. glucose e. fructose-1,6-bisphosphate

e. fructose-1,6-bisphosphate

The energy given up by electrons as they move through the electron transport chain is used in which of the following processes? () a. the production of NADH and FADH2 b. the oxidation of water c. the breakdown of glucose d. the production of CO2 e. pumping H+ across a membrane

e. pumping H+ across a membrane

Which of the following accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle? () a. release of CO2 and release of coenzyme A b. removal of coenzyme A c. formation of CO2 and synthesis of ATP d. regeneration of NAD+ e. release of CO2 and synthesis of NADH

e. release of CO2 and synthesis of NADH

Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O2) and produces CO2? () a. the combination of glycolysis and the citric acid cycle b. the citric acid cycle c. the electron transport chain d. glycolysis e. the combination of the citric acid cycle and electron transport

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