Deck 15: Energy and Metabolism

Question 1

Which of the following statements does NOT describe the safest and healthiest way for a person to lose weight?

A) A person should drastically reduce their caloric intake.
B) A person should eat a moderate intake of calories.
C) A person should include exercise in their daily routine.
D) A person should eat nutritious foods.
E) A person should maintain steady blood glucose levels.

Answer 1

A person should drastically reduce their caloric intake.

Question 2

Protein, fat, and carbohydrate catabolism all share some key steps. Which of the following statements describes a part of catabolism that these biomolecules have in common?

A) These biomolecules undergo hydrolysis.
B) These biomolecules are broken down and then react to become acetyl CoA.
C) Acetyl CoA from these biomolecules enters the citric acid cycle.
D) The carbons in these biomolecules are eventually converted into CO₂ and coenzyme A.
E) Proteins, fats, and carbohydrates share all of these catabolic steps.

Answer 2

Proteins, fats, and carbohydrates share all of these catabolic steps.

Question 3

The ATP synthesized during catabolic processes is used to provide energy for ____ processes in the cell.

A) oxidative
B) anabolic
C) slow
D) unusual
E) spontaneous

Answer 3

anabolic

Question 4

What is the first step of the metabolism of carbohydrates?

A) In the mouth, amylase hydrolyses starch into glucose, maltose, and dextrins.
B) In the stomach, amylase hydrolyses starch into glucose, maltose, and dextrins.
C) Glucose enters cells.
D) A phosphoryl group is transferred.
E) A glucose molecule is split into two pyruvates.

Question 5

Which statement best summarizes the first stage of catabolism?

A) Biomolecules are condensed in the first step.
B) Biomolecules are hydrolysed in the first step.
C) Biomolecules are reduced in the first step.
D) Biomolecules are hydrated in the first step.
E) All of the above occur in the first step of metabolism.

Question 6

Which of the following biomolecules provides fuel for the brain?

A) proteins
B) steroids
C) glucose
D) triglycerides
E) Any biomolecule can provide fuel for the brain.

Question 7

Which of the following statements best describes why proteins are metabolized when calories are severely reduced?

A) Actually, fats are metabolized during a starvation diet, not proteins.
B) Proteins have the highest energy content per gram of any of the biomolecules.
C) Proteins contain amino acids, which fuel the brain.
D) Glycogen is a type of protein.
E) There is a metabolic pathway in which glucose can be made from protein.

Question 8

Which of the following characteristics do spontaneous processes share?

A) They release heat.
B) They must be heated to occur.
C) They increase in order.
D) They can drive nonspontaneous processes.
E) They must be driven by other processes.

Question 9

What is the product of hydrolysis of a triglyceride in the first step of catabolism?

A) one molecule of glycerol and three fatty acid molecules
B) one molecule of glycerol and one fatty acid
C) three glucose molecules
D) glucose, fatty acids, and glycerol
E) Triglycerides do not undergo hydrolysis during catabolism.

Question 10

The following reactions are several steps in the conversion of acetyl coenzyme A to carbon dioxide. Which of the reactions is NOT spontaneous?

A) II only
B) IV only
C) III only
D) III and IV
E) I, III, and IV

Question 11

Whether a sugar starts out as a fructose, galactose, or glucose, it must undergo enzyme-catalyzed reactions in order to become a single type of monosaccharide so that it can go through the second stage of catabolism, glycolysis. Which monosaccharide must all of these sugars become?

A) fructose
B) galactose
C) mannose
D) talose
E) glucose

Question 12

Which of the following statements about spontaneous reactions is NOT true?

A) If a reaction is spontaneous, the reverse reaction is nonspontaneous.
B) All spontaneous reactions occur quickly.
C) Spontaneous reactions occur without input of energy.
D) Spontaneous reactions have a negative energy value.
E) Spontaneous reactions can do work.

Question 13

Which of the following changes is NOT spontaneous?

A) water flowing downhill
B) two like charges attracting each other
C) a skydiver falling toward the earth
D) salt dissolving in water
E) the hydrolysis of ATP

Question 14

Why is the metabolism of fat sometimes called "burning fat"?

A) because the fat is heated
B) because exercise is a painful activity
C) because the fat is oxidized
D) because exercise makes a person sweat and feel hot
E) because the fat melts

Question 15

Which of the following pathways directly produces acetyl CoA?

A) hydrolysis of proteins
B) hydrolysis of a polysaccharide
C) glycolysis
D) β-oxidation
E) All of the above directly produce acetyl CoA.

Question 16

Which of the following statements describes a necessary role of glucose in the body?

A) Glucose supplies energy to the brain.
B) Proteins are composed of glucose.
C) Fat stores are composed of glucose.
D) Glucose is the only source of energy for the entire body.
E) All of the above are true.

Question 17

Under what circumstances are amino acids metabolized?

A) They are metabolized during starvation.
B) All dietary amino acids are metabolized.
C) Essential amino acids are always metabolized.
D) Proteins are not hydrolyzed into proteins under any circumstance.
E) They are metabolized under anaerobic conditions.

Question 18

Catabolism is often called

A) oxidative phosphorylation.
B) cellular respiration.
C) anabolism.
D) oxidation-reduction.
E) the citric acid cycle.

Question 19

Fats, proteins and carbohydrates are all broken down into __________, the central molecule of metabolism.

A) glucose
B) carbon dioxide
C) acetyl coenzyme A
D) ATP
E) pyruvate

Question 20

Which of the following choices is NOT a function of cellular respiration?

A) It converts food and oxygen to CO₂ and water.
B) It extracts energy from food.
C) It stores energy in the form of ATP.
D) It builds proteins and synthesizes DNA.
E) It reduces coenzymes NAD⁺ and FAD.

Question 21

A "high-energy bond" is a bond that

A) releases energy when it is broken.
B) is very strong.
C) is very stable.
D) is weak.
E) requires energy to form.

Question 22

What is the purpose of coenzyme A in metabolism?

A) Coenzyme A delivers ADP so that it can be phosphorylated to become ATP.
B) Coenzyme A delivers ATP so that it can be dephosphorylated to become ADP.
C) Coenzyme A provides the energy for catabolism to occur.
D) Coenzyme A transfers electrons to where they need to go.
E) Coenzyme A transfers acyl groups.

Question 23

During glucose metabolism, the following reaction occurs. What is this reaction called?

A) phosphoryl group transfer reaction
B) hydrolysis
C) hydration
D) dehydration
E) oxidation

Question 24

When acetyl coenzyme A is hydrolyzed during the citric acid cycle, which bond in the molecule is broken?

A)a
B)b
C)c
D)d
E)e

Question 25

Which of the following molecules could be transferred by coenzyme A?

A) None of these could be transferred by Coenzyme A.
B) Only I could be transferred.
C) I and II could be transferred by Coenzyme A.
D) Only III could be transferred.
E) All of these could be transferred by Coenzyme A.

Question 26

The first step of glycolysis is phosphorylating glucose to make glucose 6-phosphate as shown below. Which of the following statements about this reaction is TRUE? Glucose + P_i → glucose 6-phosphate + H₂O ΔG = + 3.3 kcal/mol

A) This reaction releases energy.
B) This reaction is spontaneous.
C) This reaction cannot occur in the body.
D) This reaction must be coupled to another reaction to occur.
E) An enzyme is required to provide the energy for this reaction.

Question 27

During ATP hydrolysis, to what molecule is a phosphoryl group transferred?

A) another ATP
B) ADP
C) AMP
D) water
E) P_i

Question 28

Which of the following molecules is an acetyl group?

A)a
B)b
C)c
D)d
E)e

Question 29

During fatty acid oxidation, a fatty acid must react with coenzyme A to become a fatty acyl-CoA, as shown below. In the body, the reaction above is coupled to the hydrolysis of two phosphate groups from ATP as shown below: Which of the following equations is the correct calculation of the overall free energy of the coupled reaction?

A) ΔG_overall = 7.0 kcal/mol + 15.7 kcal/mol
B) ΔG_overall = 7.0 kcal/mol  15.7 kcal/mol
C) ΔG_overall = 15.7 kcal/mol + 7.0 kcal/mol
D) ΔG_overall = 7 kcal/mol  15.7 kcal/mol
E) ΔG_overall = 7 kcal/mol  15.7 kcal/mol

Question 30

Energy is only released during a reaction when a bond is formed, never when it is broken. Which bond is formed during ATP hydrolysis, releasing energy?

A) a C-H bond
B) a C-P bond
C) a H-O bond
D) a P-O bond
E) a P=O bond

Question 31

Which bond in ATP is referred to as a "high-energy bond"?

A) a C-H bond
B) a C-P bond
C) a C-O bond
D) a P-O bond
E) a P=O bond

Question 32

The structure below is acetyl coenzyme A. Select the choice in which each part of acetyl coenzyme A is correctly labeled.

A)a
B)b
C)c
D)d
E)e

Question 33

During fatty acid oxidation, a fatty acid must react with coenzyme A to become a fatty acyl-CoA, as shown below. Fatty acid + CoA → Fatty acyl - CoA ΔG = + 7.0 kcal/mol
In the body, the reaction above is coupled to the hydrolysis of two phosphate groups from ATP as shown below:
ATP → AMP + 2 P_i ΔG = 15.7 kcal/mol
Which of the following chemical equations correctly shows these two reactions coupled together?

A)a
B)b
C)c
D)d
E)e

Question 34

The partial structures of the coenzymes NADH and NAD⁺ are shown below. What type of reaction is this?

A) oxidation
B) reduction
C) acid-base
D) hydrolysis
E) condensation

Question 35

Which of the following terms describes the role of ATP in this reaction?

A) The hydrolysis of ATP is inhibiting this reaction.
B) The hydrolysis of ATP is a catalyst for this reaction.
C) The hydrolysis of ATP is regulating this reaction.
D) The hydrolysis of ATP is coupled to this reaction.
E) All of the above

Question 36

Which bond is broken when ATP is hydrolyzed to ADP?

A) a
B) b
C) c
D) d
E) e

Question 37

Which of the following choices correctly label each type of bond in the following molecule of ATP?

A) All are phosphate ester bonds.
B) All are phosphoanhydride bonds.
C) Both a and b are phosphoanhydride bonds and c is a phosphate ester bond.
D) Both a and b are phosphate ester bonds and c is a phosphoanhydride bonds.
E) Both a and c are phosphate ester bonds and b is a phosphoanhydride bonds.

Question 38

The following reaction is a key step in the metabolism of glucose. Which of the following molecules is formed as a result of this reaction?

A) ADP
B) H⁺
C) ATP
D) H₂O
E) P_i

Question 39

Which of the following statements bests describes how nonspontaneous reactions occur in the body?

A) Reactions that are not spontaneous do not occur in the body.
B) Enzymes make these reactions occur at a reasonable rate.
C) The heat of the body drives these reactions.
D) They are coupled to spontaneous reactions.
E) Nonspontaneous reactions occur just like spontaneous ones do, without any input of energy.

Question 40

What are the products of ATP hydrolysis?

A) ADP and P_i?
B) AMP and P_i
C) ADP and water
D) AMP and water
E) ADP, AMP, P_i, and water

Question 41

Where in the cell does glycolysis occur?

A) in the mitochondria
B) in endoplasmic reticulum
C) in the golgi complex
D) in the cytoplasm
E) in the vacuoles

Question 42

Which of the following processes does NOT occur during the citric acid cycle?

A) ADP is phosphorylated to make ATP.
B) NAD⁺ is reduced to NADH.
C) FAD is reduced to FADH₂.
D) GDP is phosphorylated to make GTP.
E) CO₂ is released.

Question 43

The net result of glycolysis is an output of energy in the form of _______ from the catabolism of a single glucose molecule.

A) 2 ATPs
B) 2 NADHs
C) 4 ATPs
D) 2 ATPs and 2 NADHs
E) 4 ATPs and 2 NADHs

Question 44

Which of the choices below best describes the purpose of the following step of glycolysis?

A) In this step, the molecule is phosphorylated to keep it in the cell.
B) In this step, the molecule is split into two, both of which will become pyruvate.
C) In this step, NADH is made.
D) In this step, energy is stored as ATP.
E) In this step, pyruvate is made.

Question 45

Which of the following pathways results in pyruvate?

A) hydrolysis
B) glycolysis
C) gluconeogenesis
D) the citric acid cycle
E) All of these pathways produce pyruvate.

Question 46

Which of the following statements about glycolysis is NOT true?

A) Glycolysis is the only energy producing metabolic pathway in the brain.
B) Glycolysis requires oxygen.
C) Anaerobic microorganisms use glycolysis for energy production.
D) Glycolysis is an important biochemical pathway in botulism.
E) Glycolysis produces pyruvate from glucose.

Question 47

Which of the following statements best describes the purpose of oxygen in the oxidation of pyruvate to acetyl CoA?

A) The oxygen is released during the reaction.
B) The oxygen is required to react with pyruvate.
C) The oxygen makes HS-CoA more reactive.
D) The oxygen regenerates NAD+ from NADH.
E) The oxygen reacts with H⁺.

Question 48

What is the relationship between the following two intermediates in glycolysis?

A) They are identical.
B) They are conformers.
C) They are enantiomers.
D) They are constitutional isomers.
E) They are diastereomers.

Question 49

As a monosaccharide goes through glycolysis, it must stay within the cell. How are the starting monosaccharide and all of the intermediates of glycolysis kept within the cell during glycolysis?

A) Nothing needs to be done to them; the molecules just stay in the cell.
B) The hydroxyl groups lose their protons and become negatively charged.
C) The molecules are phosphorylated.
D) The molecules attach to enzymes in the cytoplasm.
E) All of the above can occur.

Question 50

One of the steps of glycolysis is given below. What type of reaction is this?

A) oxidation
B) hydration
C) hydrogenation
D) dehydration
E) phosphoryl transfer

Question 51

The fate of pyruvate depends on its environment. Which of the following choices correctly matches how pyruvate reacts, what molecule it becomes, and where it goes next?

A)a
B)b
C)c
D)d
E)e

Question 52

Which of the following statements describe what can happen to pyruvate after it is produced during glycolysis? I. Pyruvate immediately enters the citric acid cycle.
II) It is oxidized.
III) It is reduced.

A) I only
B) II only
C) III only
D) II and III
E) I and II

Question 53

Which of the choices below best describes the purpose of the following step of glycolysis?

A) In this step, the molecule is phosphorylated to keep it in the cell.
B) In this step, the molecule is split into two, both of which will become pyruvate.
C) In this step, energy is stored as ATP.
D) In this step, pyruvate is made.
E) In this step, both pyruvate and ATP are made.

Question 54

Which of the choices above below describes the purpose of the following step of glycolysis?

A) In this step, the molecule is phosphorylated to keep it in the cell.
B) In this step, the molecule is split into two, both of which will become pyruvate.
C) In this step, NADH is made.
D) In this step, energy is stored as ATP.
E) In this step, pyruvate is made.

Question 55

Which of the following choices is the key outcome of the citric acid cycle?

A) Oxygen is consumed.
B) Carbon dioxide is released.
C) Biomolecules are catabolized.
D) FAD and NAD⁺ are reduced.
E) ADP is phosphorylated.

Question 56

Which of the following statements does NOT describe conditions under which lactic acid is formed?

A) Lactic acid is formed in aerobic conditions.
B) Lactic acid is formed when oxygen is depleted.
C) Lactic acid is formed during vigorous exercise.
D) Lactic acid is produced by the bacteria that cause tooth decay.
E) Actually, all of these are true.

Question 57

Lactic acid is turned back into pyruvate in the liver. Which statement best describes the body's purpose in making lactic acid from pyruvate in the first place?

A) To cause "the burn" during strenuous exercise.
B) To raise the pH of the immediate environment.
C) To produce NAD+ for use in glycolysis.
D) To produce FADH₂ for use in glycolysis.
E) To regenerate ADP.

Question 58

Which of the following is NOT a purpose of the glycolysis pathway?

A) It is a way to extract energy from glucose without the use of oxygen.
B) It is a way to extract and store energy as ATP.
C) It is a way to form pyruvate.
D) It is a way to make NADH.
E) It is a way to make FAD⁺.

Question 59

Which of the choices below best describes the purpose of the following step of glycolysis?

A) In this step, the molecule is phosphorylated to keep it in the cell.
B) In this step, the molecule is split into two, both of which will become pyruvate.
C) In this step, NADH is made.
D) In this step, energy is stored as ATP.
E) In this step, pyruvate is made.

Question 60

Which of the following statements about glycolysis is TRUE?

A) In every step of glycolysis, energy is stored as ATP.
B) A phosphate group is on every intermediate.
C) Glycolysis is an aerobic process.
D) Any sugar can be converted to pyruvate through glycolysis.
E) All of the above statements are true.

Question 61

What is the identity of I in the following diagram of the citric acid cycle?

A) acetate
B) GTP
C) NADH
D) FADH₂
E) carbon dioxide

Question 62

L-malate is an intermediate in the citric acid cycle. What does the L imply about L-malate?

A) L-malate is highly reactive.
B) L-malate is non-reducible.
C) L-malate is chiral.
D) L-malate is an amino acid.
E) L-malate is a lipid.

Question 63

The following is step 3 of the citric acid cycle. What is the functional group transformation that occurs in the first part of this step?

A) A ketone and an alcohol change positions.
B) An alcohol becomes a ketone.
C) The -COO^- is transformed.
D) The alcohol becomes an aldehyde.
E) A carbon-carbon double bond is added.

Question 64

What is the last stage of metabolism for glucose, fatty acids and some amino acids?

A) glycolysis
B) β-oxidation
C) pyruvate catabolism
D) hydrolysis
E) the citric acid cycle

Question 65

Which of the following choices is NOT a common name for the citric acid cycle?

A) CAC
B) TCA cycle
C) Krebs cycle
D) tricarboxylic acid cycle
E) All of these are common names of the citric acid cycle.

Question 66

Which of the following statements best describes what is illustrated in this diagram?

A) This diagram illustrates the carbon balance of the citric acid cycle.
B) This diagram illustrates the electron balance of the citric acid cycle.
C) This diagram illustrates the oxygen balance of the citric acid cycle.
D) This diagram illustrates the hydrogen balance of the citric acid cycle.
E) All of the above are illustrated in this diagram.

Question 67

The citric acid cycle is a unique metabolic pathway because it is cyclic. Which statement best describes how it is cyclic?

A) It is cyclic because oxaloacetate is regenerated.
B) It is cyclic because FAD and NAD⁺ are reduced.
C) It is cyclic because CO₂ is regenerated.
D) It is cyclic because it is linked with oxidative phosphorylation.
E) All of the above are reasons that the citric acid cycle is cyclic.

Question 68

The following is step 8 of the citric acid cycle. During this step, NAD⁺ is ________ while L-malate is ________.

A) phosphorylated; isomerized
B) isomerized; dehydrated
C) oxidized; reduced
D) reduced; oxidized
E) hydrated; dehydrated

Question 69

The following is step 3 of the citric acid cycle. During this step, NAD⁺ is ________, while isocitrate is ________.

A) phosphorylated; isomerized
B) isomerized; dehydrated
C) oxidized; reduced
D) reduced; oxidized
E) hydrated; dehydrated

Question 70

Two molecules of carbon dioxide are released for every turn of the citric acid cycle. What happens to those molecules of carbon dioxide?

A) They are used in anabolic processes.
B) They stay within the citric acid cycle, contributing to the cyclic nature of the pathway.
C) They are exhaled.
D) They are excreted in urine.
E) They undergo oxidative phosphorylation.

Question 71

The citric acid cycle has a unique circular appearance when written due to the regeneration of oxaloacetate. Which of the following molecules is oxaloacetate?

A)a
B)b
C)c
D)d
E)e

Question 72

According to the diagram below, what happens to the four atoms that begin the citric acid cycle in oxaloacetate?

A) All four atoms continue around the cycle over and over again.
B) Two of the atoms continue around the cycle a second time and two atoms are released from the cycle.
C) One of the atoms continues around the cycle a second time and three atoms are released from the cycle.
D) Three of the atoms continue around the cycle a second time and one atom is released from the cycle.
E) All four atoms are released from the cycle.

Question 73

The following is step 3 of the citric acid cycle. Isocitrate is converted into α-ketoglutarate by a(n) _______ reaction followed by _______.

A) oxidation-reduction; phosphorylation
B) phosphorylation; oxidation-reduction
C) isomerization; dehydration
D) oxidation-reduction; decarboxylation
E) hydration; decarboxylation

Question 74

Most enzymes involved in the citric acid cycle are found in the ________ of the mitochondria.

A) inner membrane
B) outer membrane
C) intermembrane space
D) matrix
E) The citric acid cycle does not occur in the mitochondria.

Question 75

In the electron-transport chain, one NADH molecule supplies the energy to phosphorylate ___ ADP molecules and one FADH₂ supplies the energy to phosphorylate ___ ADP molecules.

A) 1; 1
B) 2; 2
C) 3; 3
D) 2; 3
E) 2.5; 1.5

Question 76

The following is step 3 of the citric acid cycle. What is the identity of the molecule represented by I?

A) acetate
B) GTP
C) NADH
D) FADH₂
E) carbon dioxide

Question 77

Every acetyl CoA molecule that goes through the citric acid cycle provides enough energy to phosphorylate ____ ADP molecules to ATP.

A) 10
B) 5
C) 1
D) 100
E) 0

Question 78

What occurs during the process known as oxidative phosphorylation?

A) NADH produced during the citric acid cycle is oxidized.
B) FADH₂ produced during the citric acid cycle is oxidized.
C) ADP is phosphorylated to make ATP.
D) Oxygen is reduced to water.
E) All of the above processes occur.

Question 79

Which of the following processes does NOT occur in the mitochondria?

A) β-oxidation
B) citric acid cycle
C) oxidative phosphorylation
D) glycolysis
E) All of these occur in the mitochondria.

Question 80

Where in the cell does oxidative phosphorylation occur?

A) everywhere
B) in the ribosomes
C) in the mitochondria
D) in the cytoplasm
E) in the nucleus