Unit 2 (Week 6 Assignment Questions)

Question 1

Which of the following pathways occurs in the cytosol?

glycolysis

breakdown of pyruvate to an acetyl group

citric acid cycle

oxidative phosphorylation

all of the above

Answer 1

A

Question 2

The net products of glycolysis are

6 CO2, 4 ATP, and 2 NADH.

2 pyruvate, 2 ATP, and 2 NADH.

2 pyruvate, 4 ATP, and 2 NADH.

2 pyruvate, 2 GTP, and 2 CO2.

2 CO2, 2 ATP, and glucose.

Answer 2

B

Question 3

During glycolysis, ATP is produced by

oxidative phosphorylation.

substrate-level phosphorylation.

redox reactions.

all of the above.

both a and b.

Answer 3

B

Question 4

Which organic molecule supplies a two-carbon group to start the citric acid cycle?

ATP

NADH

acetyl CoA

oxaloacetate

both a and b

Answer 4

C

Question 5

The ability to diagnose tumors using [18F]-fluorodeoxyglucose (FDG) is based on the phenomenon that most types of cancer cells exhibit higher levels of

glycolysis.

pyruvate breakdown.

citric acid metabolism.

oxidative phosphorylation.

all of the above.

Answer 5

A

Question 6

In the experiment of Racker and Stoeckenius, bacteriorhodopsin was oriented in such a way that it pumped H+ into a vesicle. Each vesicle actually contained many molecules of bacteriorhodopsin. How would the results of the experiment have been affected if 50% of the bacteriorhodopsin molecules pumped H+ into the vesicle and 50% pumped H+ out of the vesicles?

The same amount of ATP would be made in the presence of light, and no ATP would be made in the dark.

More ATP would be made in the presence of light, and no ATP would be made in the dark.

No ATP would be made in the presence of light, and no ATP would be made in the dark.

No ATP would be made in the presence of light, but some ATP would be made in the dark.

Some ATP would be made in the presence of light, and some ATP would be made in the dark.

Answer 6

C

Question 7

Certain drugs, which are called ionophores, cause the mitochondrial membrane to be highly permeable to H+. How would such drugs affect oxidative phosphorylation?

Movement of electrons down the ETC would be inhibited.

ATP synthesis would be inhibited.

ATP synthesis would be unaffected.

ATP synthesis would be stimulated.

Both a and b would occur.

Answer 7

B

Question 8

The source of energy that directly drives the synthesis of ATP during oxidative phosphorylation is the

oxidation of NADH.

oxidation of glucose.

oxidation of pyruvate.

H+ electrochemical gradient.

reduction of O2.

Answer 8

D

Question 9

Compared with oxidative phosphorylation in mitochondria, anaerobic respiration in bacteria differs in that

more ATP is made.

ATP is made only via substrate-level phosphorylation.

O2 is converted to H2O2 rather than H2O.

something other than O2 acts as a final electron acceptor of the ETC.

both b and d occur.

Answer 9

D

Question 10

When conditions in a muscle become anaerobic during strenuous exercise, why is it necessary to convert pyruvate to lactate?

to decrease NAD+ and increase NADH

to decrease NADH and increase NAD+

to increase NADH and increase NAD+

to decrease NADH and decrease NAD+

to keep oxidative phosphorylation running

Answer 10

B

Question 11

The electron transport chain is so named because electrons are transported from one component to another. Describe the purpose of the ETC.

Answer 11

The purpose of the electron transport chain is to pump H+ across the inner mitochondrial membrane to establish an H+ electrochemical gradient. When H+ flow back across the membrane through ATP synthase, ATP is synthesized.

Question 12

What causes the rotation of the γ subunit of ATP synthase? How does this rotation promote ATP synthesis?

Answer 12

The movement of H+ through the contact site between the c and a subunits causes the γ subunit to rotate. As it rotates, it sequentially alters the conformation of the β subunits, where ATP is made. This causes (1) ADP and Pi to bind with moderate affinity, (2) ADP and Pi to bind very tightly such that ATP is made, and (3) ATP to be released.

Question 13

How is glucose breakdown regulated to avoid the overproduction of ATP and NADH? What would be some potentially harmful consequences if glucose metabolism was not regulated properly?

Answer 13

The phases of glucose metabolism are regulated in a variety of ways. For example, key enzymes in glycolysis and the citric acid cycle are regulated by the availability of their substrates and by feedback inhibition. The electron transport chain is regulated by the ATP/ADP ratio. Such regulation ensures that a cell does not waste energy making ATP when it is in sufficient supply. Also, the production of too much NADH is potentially harmful because at high levels it has the potential to haphazardly donate its electrons to other molecules and promote the formation of free radicals, highly reactive chemicals that damage DNA and cellular proteins.

Question 14

Discuss the advantages and disadvantages of aerobic respiration, anaerobic respiration, and fermentation.

Answer 14

Fill In

Question 15

Read more about PET scans in other sources. Which types of cancers are most easily detected by this procedure, and which types are not readily detected? Is the ability to detect cancer via a PET scan related to the level of oxygen within a tumor?

Answer 15

Fill In

Question 16

Which of the following is the best description of the process of cellular respiration?

Multiple choice question.

A means to extract energy from organic molecules

A means to utilize ATP in cells

A means to extract energy from oxygen

A means to extract energy from inorganic molecules

Answer 16

A

Question 17

The main product of cellular respiration is

Multiple choice question.

oxygen

ATP

carbon dioxide

organic molecules

Answer 17

B

Question 18

Glucose contains covalent bonds that store a large amount of ______.

Multiple choice question.

water

kinetic energy

ATP

chemical energy

Answer 18

chemical energy

Question 19

What is the order of glucose breakdown?

Answer 19

Glycolysis, breakdown of pyruvate, citric acid cycle, and oxidative phosphorylation

Question 20

Which of the following are end products of glycolysis?

Multiple select question.

Pyruvate

Oxygen gas

ATP

NADH

Answer 20

Pyruvate

ATP

NADH

Question 21

The metabolic reactions that a cell uses to get energy from food molecules and release waste products are collectively called ______.

Multiple choice question.

cellular respiration

chemical respiration

oxidative phosphorylation

glycolysis

Answer 21

cellular respiration

Question 22

Glycolysis occurs in the ______.

Multiple choice question.

plasma membrane

mitochondrion

cristae membrane

cytosol

Answer 22

cytosol

Question 23

The primary aim of cellular respiration is to produce molecules of __________ which provide energy to the cell.

Answer 23

ATP, adenosinetriphosphate, or adenosine triphosphate

Question 24

The pyruvate molecule produced in glycolysis undergoes a reaction which results in the production of one __________ group and one CO2 molecule.

Answer 24

acetyl, acetyl CoA, or acetyl-CoA

Question 25

The ______ bonds in glucose store large amounts of energy.

Answer 25

Covalent

Question 26

During glycolysis, one molecule of | ______, is broken down into two molecules of pyruvate, driving the synthesis of ATP.

Answer 26

Glucose

Question 27

Select all that apply What four pathways are involved in the breakdown of glucose to carbon dioxide and water? Multiple select question. Photosynthesis Citric acid cycle Oxidative phosphorylation Breakdown of pyruvate Glycolysis Gluconeogenesis

Answer 27

Citric acid cycle Oxidative phosphorylation Breakdown of pyruvate Glycolysis

Question 28

Tumors provide a favorable environment for glycolysis because their internal regions tend to be deficient in ______. Multiple choice question. NAD+ glucose oxygen ATP

Answer 28

oxygen

Question 29

Glycolysis is the breakdown of glucose into ______. Multiple choice question. two pyruvate molecules six carbon dioxide molecules two citric acid molecules three acetyl groups

Answer 29

two pyruvate molecules

Question 30

While glycolysis occurs in the ___________ in eukaryotic cells, the remaining steps of respiration occur in the ___________ of the cell.

Answer 30

Cytosol/mitochondria

Question 31

True or false: Glycolysis occurs in the mitochondria. True false question. True False

Answer 31

False

Question 32

When a carbon dioxide is removed from pyruvate, the product is a(n) _______ group, which then attaches to coenzyme A.

Answer 32

Acetyl

Question 33

What are the products of the breakdown of a single pyruvate molecule? Multiple select question. One ATP molecule Two NADH molecules One acetyl group One CO2 Two acetyl groups One NADH molecule

Answer 33

One acetyl group One CO2 One NADH molecule

Question 34

Glycolysis involves the breakdown of one molecule of glucose into ______. Multiple choice question. one molecule of pyruvate and one molecule of acetyl-CoA one molecule of pyruvate and three molecules of CO2 three molecules of acetyl-CoA two molecules of pyruvate

Answer 34

two molecules of pyruvate

Question 35

In the first reaction of the citric acid cycle, oxaloacetate, which contains ______ carbons, is combined with acetyl-CoA, which contains ______ carbons in its acetyl group, to produce citric acid, which contains ______ carbons. Multiple choice question. 3; 3; 6 3; 1; 4 5; 1; 6 4; 2; 6 4; 1; 5 2; 2; 4

Answer 35

4, 2, 6

Question 36

True or false: Within tumors, glycolysis is favored under hypoxic conditions. True false question. True False

Answer 36

True

Question 37

What energy intermediates are produced in the citric acid cycle? Multiple select question. Pyruvate Acetyl-CoA NAD+ NADH GTP FADH2

Answer 37

NADH GTP FADH2

Question 38

In order for cellular respiration to continue, the pyruvate produced in glycolysis must be transported into the ______. Multiple choice question. mitochondrion stroma electron transport chain cytosol

Answer 38

mitochondrion

Question 39

During cellular respiration, acetyl-CoA is formed during a reaction that also: Multiple choice question. attaches coenzyme A to pyruvate reduces pyruvate removes a CO2 from pyruvate removes coenzyme A from pyruvate

Answer 39

removes a CO2 from pyruvate

Question 40

In the final stage of glucose metabolism, the high-energy electrons from NADH and FADH2 are removed and used to produce more ATP. This process is called _______ ____________

Answer 40

Oxidative phosphorylation

Question 41

As a result of the reactions of the citric acid cycle, the carbons from acetyl CoA are released as: Multiple choice question. NADH pyruvate CO2 ATP

Answer 41

CO2

Question 42

The structural components of the electron transport chain include which of the following? Multiple select question. Small organic molecules NADH and FADH2 Protein complexes Carbohydrate complexes Oxygen gas

Answer 42

Small organic molecules Protein complexes

Question 43

Each turn of the citric acid cycle produces ______. Multiple choice question. 2 NADH 2 NADH and 2 FADH2 3 NAD+ and 1 FAD 3 NADH and 1 FADH2 2 NAD+ and 2 FAD

Answer 43

3 NADH and 1 FADH2

Question 44

The final electron acceptor in the electron transport chain is ______. Multiple choice question. oxygen carbon dioxide FADH2 NADH

Answer 44

oxygen

Question 45

During oxidative phosphorylation, ATP synthesis is coupled to ______. Multiple choice question. the breakdown of glucose into CO2 the entry of acetyl-CoA into the citric acid cycle the synthesis of NADH and FADH2 the removal of high-energy electrons from NADH and FADH2

Answer 45

the removal of high-energy electrons from NADH and FADH2

Question 46

During oxidative phosphorylation, ATP synthase adds a phosphate group to: Multiple choice question. ATP ADP NADH NAD+ FADH2

Answer 46

ADP

Question 47

Electrons from FADH2 are transferred to succinate reductase and then to a small organic molecule called __________

Answer 47

ubiquinone, coenzymeQ, or oxygen

Question 48

In eukaryotic cells, the electron transport chain is located in the ______. Multiple choice question. cytosol outer mitochondrial membrane mitochondrial matrix inner mitochondrial membrane plasma membrane

Answer 48

inner mitochondrial membrane

Question 49

Cyanide is lethal to cells because it ______. Multiple choice question. creates holes in the mitochondrial membranes inhibits the flow of electrons along the ETC denatures two key enzymes in the citric acid cycle blocks the conversion of pyruvate to acetyl-CoA

Answer 49

inhibits the flow of electrons along the ETC

Question 50

The second event in oxidative phosphorylation is the production of ATP by the enzyme ATP __________ .

Answer 50

synthase

Question 51

During aerobic respiration, the final electron acceptor in the electron transport chain is _________

Answer 51

oxygen

Question 52

Which of the following best describes the chemical reactions of oxidative phosphorylation? Multiple choice question. NADH is reduced and ATP is produced. NADH is oxidized and ATP is produced. NADH is oxidized and ATP is consumed. NADH is reduced and ATP is consumed.

Answer 52

NADH is oxidized and ATP is produced.

Question 53

True or false: The flow of electrons through the electron transport chain requires an input of energy. True false question. True False

Answer 53

False; it is exergonic

Question 54

Arrange the molecules of the electron transport chain in the order in which they receive electrons, beginning at the top with the first molecule to receive electrons and ending at the bottom with the final electron acceptor. ``` Oxygen Cytochrome b-c1 Ubiquinone Cytochrome c Cytochrome oxidase NASDH dehydrogenase ```

Answer 54

``` NADH dehydrogenase Ubiquinone Cytochrome b-c1 Cytochrome c Cytochrome oxidase Oxygen ```

Question 55

Which of these is a light-driven H+ pump found in archaea? Multiple choice question. Chymotrypsin Calmodulin Glycophorin Bacteriorhodopsin

Answer 55

Bacteriorhodopsin

Question 56

One important component of the electron transport chain is cytochrome oxidase. Which of the following inhibits this complex? Multiple choice question. Ricin Cyanide Arsenic Tetanus toxin Snake venom

Answer 56

Cyanide

Question 57

ATP synthase functions like a ______. Multiple choice question. rotary machine lever pulley system spring

Answer 57

rotary machine

Question 58

During oxidative phosphorylation, ATP is produced by the enzyme: Multiple choice question. ATP synthase ATP oxidase ATP protease citrate synthetase

Answer 58

ATP synthase

Question 59

Which of the following molecules are used as energy sources by living organisms? Multiple select question. Sugars Amino acids Fatty acids Water Molecular oxygen

Answer 59

Sugars Amino acids Fatty acids

Question 60

When electrons are transferred to oxygen in the final step of the electron transport chain, a molecule of _____________ is produced.

Answer 60

H2O

Question 61

An environment where oxygen is absent is termed __________.

Answer 61

anaerobic or anoxic Hypoxic or dysoxic is low concentration of oxygen -- between 1 to 30% saturation

Question 62

The flow of electrons through the electron transport chain is ______. Multiple choice question. exergonic endergonic neither exergonic nor endergonic

Answer 62

exergonic

Question 63

What type of pathway produces ATP by substrate-level phosphorylation without any net oxidation of organic molecules? Multiple choice question. Fermentation Anaerobic respiration Aerobic respiration Citric acid cycle

Answer 63

Fermentation

Question 64

Bacteriorhodopsin is a proton pump found in some species of archaea. The energy that bacteriorhodopsin uses to pump protons comes from ______. Multiple choice question. ATP hydrolysis light an electron transport chain ATP synthesis

Answer 64

Light

Question 65

At the end of the electron transport chain, ______ catalyzes the transfer of electrons to O2. Multiple choice question. chaperone ubiquinone cytochrome oxidase cytochrome b-c1

Answer 65

cytochrome oxidase

Question 66

What type of motion is coupled to the synthesis of ATP by the enzyme ATP synthase? Multiple choice question. Vibration Spinning Oscillation

Answer 66

Spinning

Question 67

True or false: Some organisms can only use oxygen as a final electron acceptor. True false question. True False

Answer 67

True

Question 68

Select the organic molecules obtained from food that are most typically used as energy sources. Multiple select question. Fats Nucleotides Carbohydrates Proteins

Answer 68

Fats Carbohydrates Proteins

Question 69

What problem results from the buildup of NADH and decrease of NAD+ under anaerobic conditions? Multiple choice question. A decrease in NAD+ levels can kill the cell because NAD+ is needed to release electrons to the ETC. High concentrations of NADH can lead to the release of free radicals, which can damage DNA and proteins. No problem results. High concentrations of NADH facilitate glycolysis.

Answer 69

High concentrations of NADH can lead to the release of free radicals, which can damage DNA and proteins.

Question 70

Which term is used to describe an environment that lacks oxygen? Multiple choice question. Aerobic Anabolic Catabolic Anaerobic

Answer 70

Anaerobic

Question 71

How is ATP produced during fermentation? Multiple choice question. Substrate-level phosphorylation Oxidative phosphorylation using O2 as the final electron acceptor Oxidative phosphorylation using a molecule other than O2 as the final electron acceptor

Answer 71

Substrate-level phosphorylation

Question 72

Muscle cells overcome the buildup of NADH and decrease of NAD+ under anaerobic conditions by ______. Multiple choice question. reducing pyruvate to citrate oxidizing pyruvate to citrate oxidizing pyruvate to lactate reducing pyruvate to lactate

Answer 72

reducing pyruvate to lactate

Question 73

What is the outcome of aerobic respiration? Multiple choice question. O2 is reduced to H2O O2 is oxidized to H2O O2 and H2 are joined to form H2O H2O is broken down into O2 and H2

Answer 73

O2 is reduced to H2O

Question 74

Many organisms, including animals and yeasts, can only use _________ as a final electron acceptor in their electron transport chains.

Answer 74

Oxygen

Question 75

What happens during the fermentation reactions that occur in muscle cells? Multiple select question. NADH is converted to lactate. Pyruvate is reduced to lactate. NADH is oxidized to NAD+. Pyruvate is broken down to acetyl-CoA and CO2.

Answer 75

Pyruvate is reduced to lactate. NADH is oxidized to NAD+.

Question 76

Under anaerobic conditions, high levels of ______ may cause the production of free radicals. Multiple choice question. FADH2 NADH NAD+ FADH

Answer 76

NADH

Question 77

Which of these organic molecules can be produced during fermentation reactions? Multiple select question. Lactate Glucose Glycerol Acetyl-CoA Ethanol

Answer 77

Lactate Ethanol

Question 78

What molecule is produced during fermentation in muscle cells? Multiple choice question. Glucose Lactose Citrate Lactate

Answer 78

Lactate

Question 79

The complete breakdown of glucose in the presence of oxygen yields 34 to 38 ATP molecules, but the breakdown of glucose to lactate or ethanol yields a net of only ____________ ATP molecules.

Answer 79

2

Question 80

At the end of the electron transport chain, ______ catalyzes the transfer of electrons to O2. Multiple choice question. cytochrome b-c1 ubiquinone cytochrome oxidase chaperone

Answer 80

cytochrome oxidase

Question 81

When a muscle is working strenuously and becomes anaerobic, pyruvate from glycolysis is reduced to lactate to allow the oxidation of ______. Multiple choice question. NAD+ to NADH NADH to NAD+ nitrate to nitrite H2O to H3O+

Answer 81

NADH to NAD+

Question 82

The breakdown of glucose to lactate or ethanol as a final end product is an example of _________

Answer 82

Fermentation

Question 83

Aerobic respiration yields ______ ATP molecules per glucose, while fermentation typically yields ______ ATP molecules per glucose. 38-42 ; 2 34-38 ; 4 2 ; 34-38 4 ; 34-38 34-38 ; 2

Answer 83

34-38 ; 2

Question 84

[Quiz] If an organism is missing the transport protein for pyruvate on the mitochondrial membrane, what is the most likely effect? Question 1 options: The organism cannot carry out glycolysis The organism cannot carry out fermentation The organism cannot carry out the preparation reaction The organism cannot carry out photosynthesis

Answer 84

The organism cannot carry out fermentation WRONG

Question 85

[Quiz] Cytochrome oxidase is the last enzyme in the electron transport chain. Cyanide is a competitive inhibitor of this enzyme. Why is cyanide fatal to humans? Question 2 options: Glycolysis is inhibited The Citric Acid cycle cannot be initiated The electron transport chain is shut down Pyruvate is not converted to acetyl-CoA NAD can no longer be reduced to NADH

Answer 85

The electron transport chain is shut down

Question 86

[Quiz] What is the overall goal of cellular respiration? Question 3 options: Use the energy in glucose to make ATP Use solar energy to make ATP Use solar energy to make glucose Use the energy in glucose to break down sugars

Answer 86

Use the energy in glucose to make ATP

Question 87

[Quiz] A baker was making bread but realized that his yeast were no longer alive. What impact will this have on his bread? Question 4 options: It will not rise It will taste sour due to the increased pH It will rise too high and spread over the edges of the pan.

Answer 87

It will not rise

Question 88

[Quiz] Based on the glycolysis pathway below, what enzyme catalyzes the cleavage reaction? Hexokinase Pyruvate kinase Phosphofructokinase Fructose bisphosphate aldose Phosphoglucose isomerase

Answer 88

Fructose bisphosphate aldose

Question 89

[Quiz] Bread made with yeast is lighter and fluffier than bread made without yeast. This is because yeast Question 6 options: Carries out the citric acid cycle to produce oxygen gas, which adds bubbles to the dough Carries out fermentation to produce lactic acid, which breaks down gluten Carries out fermentation to produce carbon dioxide, which adds bubbles to the dough Carries out the citric acid cycle to produce carbon dioxide, which adds bubbles to the dough

Answer 89

Carries out fermentation to produce carbon dioxide, which adds bubbles to the dough

Question 90

[Quiz] If you have been running hard, the body often switches from cellular respiration and starts producing lactic acid. Why? Question 7 options: Cellular respiration is not as efficient as fermentation Cells have depleted their oxygen stores Lactic acid causes the number of mitochondria in cells to increase Lactic acid increases the endurance of muscles Both B and D

Answer 90

Both B and D WRONG

Question 91

[Quiz] Which of these is not the result of the citric acid cycle? Question 8 options: OAA is reformed High energy electron carriers are formed Carbon dioxide is produced ATP is made through ATP synthase

Answer 91

ATP is made through ATP synthase

Question 92

[Quiz] Why is the formation of ATP by ATP synthase referred to as oxidative phosphorylation? Question 9 options: A phosphate is transferred from oxygen to ADP to form ATP Oxygen provides the mechanical energy that is used to create ATP from ADP Oxygen is the final electron acceptor in the electron transport chain, which creates the proton gradient necessary to power ATP synthase ADP combines with oxygen to form ATP

Answer 92

Oxygen is the final electron acceptor in the electron transport chain, which creates the proton gradient necessary to power ATP synthase

Question 93

[Quiz] When pyruvate is converted to Acetyl-CoA, it loses a proton and its associated electron. This reaction is an example of Question 10 options: Oxidation Reduction Dehydration Hydrolysis

Answer 93

Hydrolysis WRONG

Question 94

[Quiz] In order to determine if the patient with the blood results shown here could complete glycolysis, what substance would you test for in her blood? Blood Metabolic Panel Blood Glucose + Glucose-6-phosphate ++ Fructose-6-phosphate ++ Fructose-1,6,bisphosphate ++ Glyceraldehyde-3-phosphate ++ 1,3-bisphosphoglycerate ++ Phosphoenolpyruvate ++ Pyruvate - ATP - Red Blood Cell Concentration - Question 11 options: Glucose-6-phosphate Fructose-6-phosphate Glyceradlehyde-3-phosphate Pyruvate Pyruvate kinase

Answer 94

Pyruvate kinase WRONG

Question 95

[Quiz] A genetic defect in some humans causes a slight decrease in the number of ATP synthase proteins on their mitochondrial membranes. What symptoms would you expect these individuals to exhibit? Question 12 options: Hyperactive thyroid Increased metabolic rate Increased growth rate Increased fatigue and lethargy

Answer 95

Increased fatigue and lethargy

Question 96

[Quiz] Why does the citric acid cycle spin twice for each glucose in cellular respiration? Question 13 options: Because it needs to make more pyruvate Because there are two acetyl-CoA formed for each glucose Because the H+ must be pumped into the intermembrane space Because the oxidative phosphorylation process take twice as long as glycolysis

Answer 96

Because there are two acetyl-CoA formed for each glucose

Question 97

[Quiz] If you wanted to test red blood cells for their ability to complete glycolysis, what compound would you try to detect? Question 14 options: Fructose-6-phosphate Aldolase Pyruvate Phosphofructokinase Dihydroxyacetone phosphate

Answer 97

Aldolase WRONG

Question 98

[Quiz] The electron transport chain is used to create a proton gradient across the mitochondrial membrane. This proton gradient represents Question 15 options: Kinetic energy Potential energy Mechanical energy Heat

Answer 98

Potential energy