Deck 23: Digestion and the Conversion of Food Into Energy

Question 1

Considering the energy changes associated with the two individual reactions below, what is the energy change associated with the energetically favorable coupled reaction?

A)- 11.2 kcal/mol
B)- 3.4 kcal/mol
C)- 7.3 kcal/mol
D)+ 3.4 kcal/mol
E)+ 11.2 kcal/mol

Answer 1

B

Question 2

Where does energy production occur in animal cells?

A)cell membrane
B)cytoplasm
C)mitochondria
D)nucleus

Answer 2

C

Question 3

Where does the hydrolysis of carbohydrates to monosaccharides begin?

A)in the stomach
B)in the saliva
C)in the liver
D)in the small intestines

Answer 3

B

Question 4

What is the classification of the reaction shown?

A)redox
B)isomerization
C)decarboxylation
D)hydrolysis

Question 5

How many reactions make up the citric acid cycle?

A)3
B)4
C)6
D)8

Question 6

If the phosphorylation of GMP to form GDP requires 7.3 kcal/mol of energy, what is the energy change associated with the hydrolysis of GDP to form GMP?

A)7.3 kcal/mol
B)-7.3 kcal/mol
C)14.6 kcal/mol
D)Not enough information is given to determine the change in energy.

Question 7

Which functional group is not contained in coenzyme A, whose structure is shown below?

A)alcohol
B)sulfhydryl
C)phosphoester
D)amide
E)aldehyde

Question 8

The addition of a phosphate group to ADP, forming ATP, is an example of what type of reaction?

A)hydration
B)hydrolysis
C)phosphorylation
D)reduction
E)decarboxylation

Question 9

How many molecules of reduced coenzymes are produced for each turn of the citric acid cycle?

A)2
B)4
C)16
D)32

Question 10

Which is not true about coenzymes?

A)Many reactions in metabolic pathways involve coenzymes.
B)When a coenzyme gains hydrogen atoms the coenzyme is an oxidizing agent.
C)Many coenzymes are involved in oxidation and reduction reactions.
D)The coenzyme nicotinamide adenine dinucleotide, NAD⁺, is a common biological reducing agent.

Question 11

Considering the energy changes associated with the individual reactions below, which reaction can be coupled with the hydrolysis of ATP to generate a coupled reaction that is energetically favorable?

A)fructose 6-phosphate + HPO₄^2- fructose 1, 6-bisphosphate + H₂O
B)succinate + HSCoA + HPO₄^2- succinyl CoA + H₂O
C)3-phosphoglycerate + HPO₄^2- 1, 3-bisphosphoglycerate + H₂O
D)All of the reactions can be coupled with the hydrolysis of ATP to generate a coupled reaction that is energetically favorable.

Question 12

Which coupled reaction properly indicates the role of the coenzyme as an oxidizing agent?

A)
B)
C)
D)

Question 13

Which is the first stage of catabolism?

A)digestion
B)citric acid cycle
C)fatty acid oxidation
D)glycolysis
E)formation of acetyl CoA

Question 14

Which is the abbreviated structure of acetyl CoA?

A)
B)
C)
D)

Question 15

Which is the sum of all of the chemical reactions that take place in an organism?

A)anabolism
B)metabolism
C)catabolism
D)citric acid cycle

Question 16

How many molecules of CO₂ are produced for each turn of the citric acid cycle?

A)1
B)2
C)4
D)8

Question 17

Considering the energy changes associated with the two individual reactions below, what coupled reaction is an energetically favorable one?

A)fructose 1, 6-bisphosphate + H₂O fructose 6-phosphate + HPO₄^2-
B)ADP + fructose 1, 6-bisphosphate ATP + fructose 6-phosphate
C)ATP + H₂O ADP + HPO₄^2-
D)ADP + fructose 6-phosphate ATP + fructose 1, 6-bisphosphate
E)ATP + fructose 6-phosphate ADP + fructose 1, 6-bisphosphate

Question 18

Which molecule contains the largest amount of stored energy?

A)
B)
C)
D)

Question 19

How many molecules of GTP are produced for each turn of the citric acid cycle?

A)1
B)2
C)4
D)8

Question 20

What is the classification of the reaction shown?

A)oxidation
B)reduction
C)decarboxylation
D)hydrolysis
E)isomerization

Question 21

How much ATP is generated for each acetyl CoA during stages [3] and [4] of catabolism?

A)4 molecules of ATP
B)5 molecules of ATP
C)8 molecules of ATP
D)10 molecules of ATP
E)16 molecules of ATP

Question 22

How many reactions in the citric acid cycle generate FADH₂?

A)0
B)1
C)3
D)8

Question 23

Why is hydrogen cyanide, HCN, poisonous?

A)HCN is a strong acid, dramatically altering the pH in cells.
B)Cyanide ions (^-CN)irreversibly bind to the Fe³⁺ ion of cytochrome oxidase.
C)Cyanide ions (^-CN)irreversibly bind to acetyl CoA.
D)Cyanide ions (^-CN)irreversibly bind to NAD⁺.

Question 24

Where does the electron transport chain process take place?

A)in the inner membrane of mitochondria
B)in the outer membrane of mitochondria
C)in the intermembrane space of mitochondria
D)in the matrix of mitochondria

Question 25

In which stage of metabolism are biomolecules degraded into two-carbon acetyl units?

A)Stage [1]
B)Stage [2]
C)Stage [3]
D)Stage [4]

Question 26

Which is the primary energy-carrying molecule in metabolic pathways?

A)AMP
B)ATP
C)NADH
D)Acetyl CoA
E)FADH₂

Question 27

Which intermediate in the citric acid cycle contains two chirality centers?

A)
B)
C)
D)

Question 28

What is the primary function of the citric acid cycle in metabolism?

A)to break down food molecules into smaller components so they can be absorbed by the blood
B)to synthesize ATP from the energy produced in the hydrolysis of citric acid
C)to provide the enzymes necessary to aid in the hydrolysis of carbohydrates, proteins, and lipids
D)to convert acetyl groups to CO₂ molecules and provide reduced coenzymes for the electron transport chain

Question 29

In which region of a mitochondrion would the pH be lower?

A)the matrix
B)the intermembrane space
C)the inner mitochondrial membrane
D)all regions of a mitochondrion have the same pH

Question 30

Which product(s)of the citric acid cycle are funneled into the electron transport chain?

A)ATP
B)NAD⁺ and FAD
C)NADH, FADH₂, and H⁺
D)NADH, FADH₂, H⁺, and ATP

Question 31

Which intermediate in the citric acid cycle is a secondary alcohol?

A)
B)
C)
D)
E)Two of the intermediates above are secondary alcohols.

Question 32

Which is the enzyme that hydrolyzes triacylglycerols?

A)acetyl CoA
B)protease pepsin
C)amylase
D)lipase

Question 33

Which is not a reaction found in stage [2] of catabolism?

A)fatty acid oxidation
B)glycolysis
C)oxidative phosphorylation
D)amino acid catabolism

Question 34

In which stage of catabolism is starch hydrolyzed to glucose with the aid of the enzyme amylase?

A)Stage [1]
B)Stage [2]
C)Stage [3]
D)Stage [4]

Question 35

How many reactions in the citric acid cycle generate NAD⁺?

A)0
B)1
C)3
D)8

Question 36

Which is an oxidizing agent?

A)Fe²⁺
B)NAD⁺
C)FADH₂
D)ATP

Question 37

Which best describes the function of the coenzymes NAD⁺ and FAD in catabolic pathways?

A)competitive inhibitors of the enzymes present in each pathway
B)non-competitive inhibitors of the enzymes present in each pathway
C)oxidizing agents that accept electrons and hydrogen ions from molecules undergoing oxidation
D)transport molecules that carry acetyl units to or from the different stages of metabolism

Question 38

Which is the major product of stage [2] of catabolism?

A)NADH
B)acetyl CoA
C)GTP
D)CO₂

Question 39

Which statement concerning the digestion of food groups is incorrect?

A)Carbohydrates are ultimately broken down to glucose and other monosaccharides.
B)Triacylglycerols are ultimately broken down by lipases into glycerol and fatty acids.
C)Proteins are ultimately broken down by proteases into amino acids.
D)Polysaccharides are ultimately broken down to nucleotides.

Question 40

At which stage of metabolism is the most energy in the form of ATP produced?

A)electron transport chain and oxidative phosphorylation
B)digestion
C)citric acid cycle
D)transcription

Question 41

The primary function of the electron transport chain and oxidative phosphorylation is which of the following?

A)to provide electrons and energy for the phosphorylation of ATP
B)to synthesize the reduced coenzymes necessary for digestion
C)to oxidize the reduced coenzymes NADH and FADH₂, and provide energy for the synthesis of ATP
D)to transport electrons from ATP to ADP, and synthesize acetyl CoA molecules

Question 42

Coenzyme A is a biological oxidizing agent used to convert alcohols to carbonyl-containing compounds.

Question 43

Step 7 of the citric acid cycle is shown. Which statement best describes what occurs in this step?

A)Fumarate undergoes hydrolysis with the aid of the enzyme fumarase.
B)Fumarate undergoes reduction with the aid of the cofactor fumarase.
C)Fumarate undergoes hydrogenation with hydrogens and electrons provided by the enzyme fumarase.
D)Fumarate undergoes hydration with the aid of the enzyme fumarase.

Question 44

Step 7 of the citric acid cycle is shown. Which statement best describes what occurs in this step?

A)Fumarate undergoes hydrolysis with the aid of the enzyme fumarase.
B)Fumarate undergoes reduction with the aid of the cofactor fumarase.
C)Fumarate undergoes hydrogenation with hydrogens and electrons provided by the enzyme fumarase.
D)Fumarate undergoes hydration with the aid of the enzyme fumarase.

Question 45

The final stage of the electron transport chain forms water in an anaerobic process.

Question 46

Energy released from H⁺ movement in the electron transport chain fuels the phosphorylation of ADP.

Question 47

Oxaloacetate is the starting material in the first step of the citric acid cycle and the product of the last step. The last step of the citric acid cycle, the oxidation of malate to oxaloacetate, is shown. What is the structure of oxaloacetate?

A)
B)
C)
D)

Question 48

Which statement best describes how the interconversion of ATP and ADP is responsible for storing and providing energy for cellular reactions?

A)The energy stored in ADP is released when ATP is synthesized.
B)The energy required to phosphorylate ADP is stored in ATP, and released when ATP undergoes hydrolysis.
C)The energy released in the phosphorylation of ADP can be coupled with unfavorable reactions within the cell.
D)The energy required to hydrolyze ATP comes from the energy producing reactions in the cell; the energy lost is then stored in ATP.

Question 49

Oxaloacetate is the starting material in the first step of the citric acid cycle and the product of the last step. The last step of the citric acid cycle, the oxidation of malate to oxaloacetate, is shown. What is the structure of oxaloacetate?

A)
B)
C)
D)

Question 50

The terms phosphorylation and oxidative phosphorylation may be used interchangeably.

Question 51

Coenzyme A is synthesized in cells from pantothenic acid, vitamin B₅.

Question 52

The conversion of Fe³⁺ to Fe²⁺ in the electron transport chain is an example of Fe³⁺ acting as an oxidizing agent.

Question 53

The citric acid cycle is also called the tricarboxylic acid cycle (TCA cycle).

Question 54

In the electron transport chain, H⁺ ions are pumped across the inner membrane of the mitochondrion, forming a high concentration of H⁺ ions in the intermembrane space, thus creating a potential energy gradient.

Question 55

All steps of the citric acid cycle are enzyme catalyzed.

Question 56

NAD⁺ is the abbreviation for nicotinamide adenine dinucleotide.

Question 57

The electron transport chain is a multistep process that relies on five enzyme systems as well as mobile electron carriers.

Question 58

Since more energy is released from the hydrolysis of creatine phosphate than is needed for the phosphorylation of ADP, the coupling of these two reactions results in the formation of ATP from ADP.

Question 59

The citric acid cycle comprises stage [4] of metabolism.

Question 60

H⁺ ions generated by reactions in the electron transport chain, as well as H⁺ ions present in the matrix of the mitochondria, are pumped across the inner mitochondrial membrane into the intermembrane space at three different sites.

Question 61

The rate of the citric acid cycle depends on the body's need for energy. When energy demands are low and NADH concentration is high, the cycle is inhibited.

Question 62

Stage [3] of catabolism is sometimes called aerobic respiration.

Question 63

The structure of flavin adenine dinucleotide (FAD)is shown here.

Question 64

Coenzyme A, NADH, and FAD all contain phosphate groups.

Question 65

Two electrons are donated by each NADH in the electron transport chain.

Question 66

The cleavage of a protein with chymotrypsin occurs in stage [1] of catabolism.

Question 67

The structure of coenzyme A contains amine and amide functional groups.

Question 68

Within the cell, energy production occurs in the matrix of the mitochondrion.

Question 69

The reaction shown below requires the overall input of energy.

Question 70

Any energy requiring reaction can be coupled with ATP hydrolysis to create an energetically favorable coupled reaction.

Question 71

Acetyl CoA contains an acetyl group bonded to coenzyme A by a thioester bond.

Question 72

Each NADH enters the electron transport chain at complex I in the inner mitochondrial membrane and the resulting cascade of reactions produces enough energy to synthesize 4 ATPs.

Question 73

The product of the catabolic pathways is different for proteins, triacylglycerols, and carbohydrates.

Question 74

Part [2] of the citric acid cycle includes two separate decarboxylation reactions and a hydrolysis reaction.

Question 75

GTP is a high energy compound.

Question 76

The primary function of the citric acid cycle in metabolism is to synthesize ATP from the energy produced in the hydrolysis of citric acid.

Question 77

The primary function of the electron transport chain and oxidative phosphorylation is to provide electrons for the hydrolysis of ATP.

Question 78

Anabolism is an energy releasing process that involves the synthesis of large molecules from smaller ones.

Question 79

The cells in heart tissue have more mitochondria than the cells in bone tissue.

Question 80

The energy produced by the citric acid cycle is stored in the bonds of a nucleoside triphosphate and reduced coenzymes.