Deck 8: How Cells Make Atp: Energy-Releasing Pathways

Question 1

What is the series of reactions in which the acetyl portion of acetyl CoA is degraded to CO₂ and ATP is synthesized?

A) Glycolysis
B) Citric acid cycle
C) Formation of acetyl CoA
D) Electron transport and chemiosmosis
E) Dehydrogenations

Answer 1

B

Question 2

What does the oxidative decarboxylation of two pyruvates yield?

A) 2 G3P
B) 2 glucose molecules
C) 2 ATP + 4 CO₂ + 2 NADH
D) 1 fructose-1,6-bisphosphate
E) 2 acetyl CoA + 2 CO₂ + 2 NADH

Answer 2

E

Question 3

During the first phase of glycolysis, two ____ reactions take place to transfer a phosphate group from ATP to the sugar because glucose is relatively stable and not easily broken down.

A) redox
B) exergonic
C) metabolic
D) hydrolysis
E) phosphorylation

Answer 3

E

Question 4

In the electron transport chain, exergonic redox processes drive the endergonic reaction in which

A) pyruvate is converted to acetyl CoA.
B) ATP is produced by phosphorylation of ADP.
C) G3P is produced from phosphorylation of ADP.
D) ADP is produced by dephosphorylation of ATP.
E) glucose is produced from phosphorylation of ADP.

Question 5

Which reaction is the aerobic respiration of glucose?

A) C₆H₁₂O₆ + 6 H₂O → 6 CO₂ + 12 H₂ + energy
B) C₄H₁₂O₄ + 2 H₂O + 6 CO₂ → 6 O₂ + ATP + energy
C) C₄H₁₂O₄ + 12 O₂ + 6 H₂O → 6 CO₂ + ATP + energy
D) C₆H₁₂O₆ + 6 O₂ + 6 H₂O → 6 CO₂ + 12 H₂O + energy
E) C₄H₁₂O₂ + 6 O₂ + ATP → 6 CO₂ + 12 H₂O + energy

Question 6

In glycolysis, a phosphorylated sugar (fructose-1,6-bisphosphate) is split, forming two molecules of

A) ADP.
B) G3P.
C) glucose.
D) citric acid.
E) acetyl CoA.

Question 7

In which of the following reactions is pyruvate degraded and combined with coenzyme A to form acetyl CoA?

A) Formation of acetyl CoA
B) Citric acid cycle
C) Glycolysis
D) Decarboxylations
E) Electron transport and chemiosmosis

Question 8

During the citric acid cycle, each acetyl group entering the cycle yields

A) 1 ATP, 2 NADH, and 3 FADH₂.
B) 1 ATP, 3 NADH, and 1 FADH₂.
C) 3 ATP, 2 NADH, and 1 FADH₂.
D) 4 ATP, 2 NADH, and 1 FADH₂.
E) 1 ATP, 2 NADH, and 4 FADH₂.

Question 9

A glucose molecule that is metabolized via aerobic respiration has been completely broken down and released as CO₂ by the end of

A) glycolysis.
B) fermentation.
C) the citric acid cycle.
D) the electron transport chain.
E) ATP synthesis in the mitochondria.

Question 10

Glycolysis yields a net energy profit of ____ ATP molecules per molecule of glucose.

A) no
B) one
C) two
D) four
E) six

Question 11

Which reactant of aerobic respiration is oxidized?

A) Water
B) Oxygen
C) Glucose
D) Energy
E) Carbon dioxide

Question 12

Which is a product from the first reaction of the citric acid cycle?

A) ATP
B) NAD⁺
C) Citrate
D) Phosphate
E) Acetyl-CoA

Question 13

What is the chemical reaction illustrated in the figure? ​

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A) Fermentation
B) The first step in the citric acid cycle
C) The energy investment phase of glycolysis
D) Part of the electron transport chain
E) The energy capture phase of glycolysis

Question 14

During chemiosmosis, what must be transferred from NADH and FADH₂ to electron acceptor molecules?

A) Protons
B) Electrons
C) ATP molecules
D) ADP molecules
E) Water molecules

Question 15

In glycolysis, glucose receives two phosphate groups from ____, thus forming fructose-1,6-bisphosphate.

A) ADP
B) ATP
C) G3P
D) a bisphosphate group
E) fructose-1,6-bisphosphate

Question 16

After the conversion of pyruvate molecules to acetyl CoA molecules, how many NADH molecules have been produced from one glucose molecule?

A) One
B) Two
C) Three
D) Four
E) Five

Question 17

The energy released during the chain of electron transport molecules is used to create a(n) ____ gradient across the inner mitochondrial membrane for chemiosmosis.

A) ADP
B) ATP
C) proton
D) oxygen
E) electron

Question 18

Where does the citric acid cycle take place in a eukaryotic cell?

A) Nucleus
B) Cytosol
C) Mitochondrial matrix
D) Endoplasmic reticulum
E) Mitochondrial membrane

Question 19

Which of the following is a series of reactions in which glucose is degraded to pyruvate and electrons are transferred to carriers?

A) Formation of acetyl CoA
B) Citric acid cycle
C) Glycolysis
D) Decarboxylations
E) Electron transport and chemiosmosis

Question 20

In glycolysis, a six-carbon glucose molecule is converted into two three-carbon molecules of

A) citrate.
B) acetate.
C) pyruvate.
D) oxaloacetate.
E) coenzyme A

Question 21

The complete aerobic metabolism of one molecule of glucose yields a maximum of how many ATPs?

A) 2
B) 4
C) 18
D) 32 to 34
E) 36 to 38

Question 22

Saturated fatty acids store more energy than unsaturated fatty acids. Based on your knowledge of aerobic respiration, you draw this conclusion because saturated fatty acids

A) lack phosphate.
B) are deaminated.
C) contain more ATP.
D) are more highly reduced.
E) contain more ester linkages.

Question 23

The electron transport chain forms a concentration gradient for H+, which diffuses through ATP synthase complexes, producing ____.

A) ATP
B) FAD
C) G3P
D) NADH
E) pyruvate

Question 24

What is the reaction in which part of a carboxyl group (-COOH) is removed from the substrate as a molecule of CO₂?

A) Glycolysis
B) Pyruvate
C) Decarboxylation
D) Phosphorylation
E) Dehydrogenation

Question 25

What is the function of coenzyme Q?

A) To reduce glucose
B) To oxidize glucose
C) To transfer electrons
D) To transfer phosphate to ATP
E) To provide energy in the citric acid cycle

Question 26

What is the reaction in which two hydrogen atoms are removed from the substrate and transferred to NAD+ or FAD?

A) Dehydrogenation
B) Pyruvate
C) Decarboxylation
D) Glycolysis
E) Citric acid cycle

Question 27

During aerobic respiration, what molecule is degraded to form acetyl coenzyme A?

A) NAD
B) FADH
C) Glucose
D) Pyruvate
E) Coenzyme A

Question 28

What is it called when ATP synthesis is coupled to the redox reactions in the electron transport chain?

A) Phosphorylation
B) Anaerobic respiration
C) Oxidative phosphorylation
D) Redox reactions
E) Fermentation

Question 29

How does anaerobic respiration differ from aerobic respiration?

A) Anaerobic respiration produces CO₂.
B) Anaerobic respiration produces ATP.
C) Anaerobic respiration involves an electron transport chain.
D) Anaerobic respiration utilizes O₂ as the terminal electron acceptor.
E) Anaerobic respiration utilizes NO₃− as the terminal electron acceptor.

Question 30

Which of the following statements about lactic acid fermentation is FALSE?

A) It uses glucose as a substrate.
B) It is inefficient compared to aerobic respiration.
C) It produces two ATP molecules for every glucose molecule.
D) Oxygen is the final electron acceptor of this pathway.
E) Glycolysis is the only energy-yielding step of this pathway.

Question 31

Peter Mitchell demonstrated ATP production by aerobic bacteria to prove what process?

A) Glycolysis
B) Hydrolysis
C) Fermentation
D) Chemiosmosis
E) Citric acid cycle

Question 32

Which of the following molecules can be used as a substrate for cellular respiration?

A) Glucose only
B) Glucose and lipids only
C) Glucose and proteins only
D) Glucose, lipids, and proteins only
E) Glucose, lipids, proteins, and fatty acids

Question 33

Which of the following steps in the citric acid cycle directly produces a molecule of ATP (or GTP)?

A) Citrate → isocitrate
B) Succinate → fumarate
C) Malate → oxaloacetate
D) Succinyl CoA → succinate
E) Isocitrate → α-ketoglutarate

Question 34

What is it called when a phosphate group is transferred to ADP from a phosphorylated intermediate?

A) Substrate-level phosphorylation
B) Oxidative phosphorylation
C) Phosphorylation
D) Succinate dehydrogenase
E) Succinyl CoA synthetase

Question 35

In which of the following aerobic respiration stages does a chain of several electrons transport molecules and release energy to form a proton gradient?

A) Formation of acetyl CoA
B) Citric acid cycle
C) Electron transport and chemiosmosis
D) Glycolysis
E) Dehydrogenations

Question 36

Which of the following is an exploited product of lactate fermentation?

A) Butter
B) Beer
C) Yogurt
D) Ice cream
E) Loaf of bread

Question 37

What is the role of the oxygen molecules required for aerobic respiration?

A) To form ATP
B) To produce CO₂
C) To accept electrons directly from either NADH or FADH₂
D) To accept the low energy electrons at the end of the electron transport chain
E) To store high energy electrons that are passed to complex I of the electron transport chain

Question 38

In eukaryotes, where does glycolysis occur?

A) Cytosol
B) Lysosomes
C) Golgi complex
D) Mitochondrial matrix
E) Mitochondrial inner membrane

Question 39

What is the reaction in which a phosphate group is transferred from ATP to the sugar?

A) Glycolysis
B) Phosphorylation
C) Decarboxylation
D) Dehydrogenation
E) Tricarboxylic acid

Question 40

Which of the following statements about the electron transport chain is true?

A) Protons are pumped out of the mitochondria by the complexes of the electron transport chain.
B) The proton gradient established during electron transport is a form of potential energy.
C) The electron transport chain can be found in the mitochondria of aerobic bacteria and other cells.
D) The movement of protons down a concentration gradient is an endergonic process.
E) ATP synthesis associated with the electron transport chain is an example of substrate level phosphorylation.

Question 41

For each glucose molecule that begins cellular respiration, the citric acid cycle must turn once.

Question 42

Briefly describe how the same pathways that oxidize glucose can also metabolize proteins.

Question 43

Briefly describe the two phases of glycolysis (energy investment and energy capture). Explain why glycolysis requires an initial investment of energy.

Question 44

An example of a(n) anabolic reaction is the splitting of a polysaccharide into monosaccharides.

Question 45

During fermentation, the immediate fate of the electrons in NADH is that they

A) are transferred to the electron transport chain.
B) are transferred to an organic molecule.
C) are transferred to O₂.
D) are used to make CO₂.
E) are used to form H₂O.

Question 46

Compare aerobic and anaerobic pathways used by cells to extract energy from organic molecules. Include the mechanism of ATP formation, the final electron acceptor, and the end products in your comparison.

Question 47

If yeast cells are incubated under anaerobic conditions, the pyruvate they produce is converted to lactate.

Question 48

In the tricarboxylic acid cycle, oxaloacetate reacts with acetyl CoA forming citrate.

Question 49

Respiration which does not use oxygen as the final electron acceptor and is performed by some prokaryotes that live in anaerobic environments, such as waterlogged soil, stagnant ponds, and animal intestines is called ______.

A) anaerobic respiration
B) fermentation
C) redox reactions
D) oxidative
E) deamination

Question 50

In liver cells, each pair NADH produced via glycolysis results in two ATP molecules in the electron transport chain.

Question 51

The reactions of the citric acid cycle take place in the matrix of the mitochondrion.

Question 52

Both alcohol fermentation and lactate fermentation are highly ____ because the fuel is only partially ____.

A) efficient; reduced
B) efficient; oxidized
C) inefficient; reduced
D) inefficient; oxidized
E) efficient; metabolized

Question 53

The stage of cellular respiration in which most of the ATP is produced is the citric acid cycle.

Question 54

Amino acids are metabolized by reactions in which the amino group (2NH₂) is first removed, this is known as ________.

A) anaerobic respiration
B) fermentation
C) deamination
D) phosphorylation
E) redox reactions

Question 55

If yeasts are grown under anaerobic conditions, pyruvate is converted first to ____ and then to ____.

A) citrate; oxaloacetate
B) acetaldehyde; lactate
C) lactate; carbon dioxide
D) acetaldehyde; ethyl alcohol
E) acetyl coenzyme A; citrate

Question 56

The downhill flow of protons through the ATP synthase complex powers the production of ATP.

Question 57

Fermentation is an anaerobic process that does not use an electron transport chain.

Question 58

For each acetyl CoA molecule that enters the citric acid cycle, two CO₂ molecules are produced.
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Question 59

Phosphofructokinase is stimulated by high levels of ATP.

Question 60

Sketch the electron transport chain and electron flow. Identify each complex and which complex(es) pump protons into the intermembrane space.

Question 61

Consider the efficiency of fermentation and explain why it is or is not an efficient process.

Question 65

Although our muscle cells contain mitochondria and normally undergo aerobic respiration, they can undergo anaerobic respiration during strenuous activity. What is the product of this process that causes muscle cramps? What is the evolutionary advantage of the ability of muscle cells to utilize anaerobic respiration?

Question 68

In the process of aerobic respiration, nitrate can function as the terminal electron acceptor in the electron transport chain.

Question 72

Explain the major difference between substrate-level phosphorylation and oxidative phosphorylation.

Question 73

Describe how cells regulate the conversion of glucose-6-phosphate to fructose-1,6-bisphosphate as catalyzed by phosphofructokinase (PFK) and how this mechanism mediates the process of aerobic respiration.