Biochemistry Test Two

Front 1

A control point outside the citric acid cycle is the reaction catalyzed by

Back 1

the pyruvate dehydrogenase complex.

Front 2

A deficiency in thiamine causes the disease beriberi. Which might you expect to have a higher than normal blood concentration in an individual with this condition?

Back 2

pyruvate

Front 3

True or False: ATP is consumed by the pyruvate dehydrogenase complex during the synthesis of acetyl CoA.

Back 3

False

Front 4

All but one of the enzymes of the citric acid cycle are found in this part of the mitochondrion:

Back 4

The mitochondrial matrix.

Front 5

Condensation of Acetyl-Co-Enzyme with oxaloacetate yields citrate

Back 5

CAC STEP 1

Condensation of Acetyl-Co-Enzyme with oxaloacetate yields citrate

Front 6

Each myosin head contains a binding site for _____ and a binding site for _____.

Back 6

Each myosin head contains a binding site for Actin and a binding site for ATP.

Front 7

Each of the following catalyzed reactions of the citric acid cycle appears to be regulated except

Back 7

fumarase

Hint 7

H

Front 8

The following compounds are all intermediates in the citric acid cycle.

Which intermediate does FAD oxidize?

Back 8

Compound 4

Hint 8

In step 6 of the CAC Compound 4 Succinate is oxidized by FAD removing two protons from the two middle carbons and yielding FADH2

Front 9

The following compounds are all intermediates in the citric acid cycle.

Which intermediate is formed from fumarate?

Back 9

Compound 5

Front 10

The following compounds are all intermediates in the citric acid cycle.

Back 10

Compound 3

Front 11

How does the reaction catalyzed by malate dehydrogenase proceed despite a ΔG°′ of 29.7 kJ/mol?

Back 11

concentrations of oxaloacetate are kept very low by rapid use in the subsequent step

Front 12

How many NADH are produced when one acetyl group is oxidized in the citric acid cycle?

Back 12

Three

Front 13

How many electrons are transferred from one acetyl group during the citric acid cycle?

Back 13

Eight

Front 14

In a muscle cell, what is the name for the bundles of myosin tails?

Back 14

thick filaments

Front 15

In eukaryotes the enzymes of the citric acid cycle are found in the ________.

Back 15

mitochondria

Front 16

In eukaryotes, the citric acid cycle occurs in the _____ and therefore requires that reactants of the citric acid cycle be transported from the _____.

Back 16

In eukaryotes, the citric acid cycle occurs in the mitochondrial matrix and therefore requires that reactants of the citric acid cycle be transported from the cytosol.

Front 17

In muscle cells, the following reaction proceeds as written, i.e., from left to right, despite having ΔG°' ≈ +30 kJ/mol. How can this occur?

Back 17

The concentration of malate must be higher than oxaloacetate for this reaction to occur in the cell.

Front 18

In which cellular location do the majority of the reactions of the citric acid cycle take place?

Back 18

the mitochondrial matrix.

Front 19

Muscle contraction is triggered

Back 19

in response to an increase in the cytoplasmic Ca2+ concentration.

Front 20

One turn of the citric acid cycle generates

Back 20

1 GTP, 3 NADH, 1 FADH2

Front 21

Pyruvate translocase is a/an ________ protein that transports ________.

Back 21

Pyruvate translocase is a/an symport protein that transports pyruvate and H + in the same direction.

Front 22

Pyruvate translocase is specific for transporting pyruvate across the inner mitochondrial membrane.

Back 22

True

Front 23

Release of succinate from succinyl-CoA can be coupled to GTP synthesis because:

Back 23

The thioester bond between succinate and CoA has a large −ΔG of hydrolysis.

Front 24

The acetyl group is carried on lipoic acid as

Back 24

a thioester

Front 25

The activity of dihydrolipoamide acetyltransferase (E2) is inhibited when the concentration of of acetyl CoA is decreased.

Back 25

False

Front 26

The activity of dihydrolipoamide dehydrogenase (E3) is inhibited by a high NADH/NAD+ ratio.

Back 26

True

Front 27

The arrangement of subunits in the PDH(pyruvate dehydrogenase) complex ensures that ________.

Back 27

Correct the product of one enzyme is delivered to the next in turn

Front 28

The citric acid cycle can be viewed as a multi-step catalyst simply because it returns to its original state after each round of reactions.

Back 28

True

Front 29

The conversion of malate to oxaloacetate has a high +ΔG (it is endergonic). It can take place because:

Back 29

The oxaloacetate product is used up in the subsequent reaction.

Front 30

The energy needed to drive muscle contraction comes from ATP hydrolysis that is carried out by

Back 30

Correct myosin heads.

Front 31

The enzyme pyruvate translocase is located ________.

Back 31

in the inner mitochondrial membrane

Front 32

The immediate electron acceptor for the majority of the oxidative reactions of the citric acid cycle is

Back 32

NAD

Front 33

The order of prosthetic groups as they act in the three proteins of the PDH(pyruvate dehydrogenase) complex is:

Back 33

E1: thiamine pyrophosphate

E2: dihydrolipoamide

E3: FAD

Front 34

The pyruvate dehydrogenase complex is composed of three distinct enzymes.

Back 34

True (E1,E2,E3)

Front 35

The pyruvate dehydrogenase complex is composed of three distinct enzymes.

Back 35

True

Front 36

The reaction catalyzed by _____ requires an enzyme bound flavin coenzyme.

Back 36

Correct succinate dehydrogenase

Front 37

The recycling of NAD allows glycolysis to continue in the absence of oxygen.

Back 37

True

Front 38

The repeating functional unit in a myofibril is called

Back 38

the sarcomere.

Front 39

The step at which acetyl CoA enters the citric acid cycle is classified as a ________ reaction.

Back 39

condensation

Front 40

The succinate dehydrogenase complex catalyzes

Back 40

the formation of a double bond in the oxidation of succinate to fumarate.

Front 41

What cellular location contains pyruvate dehydrogenase and most of the citric acid cycle enzymes?

Back 41

mitochondrial matrix

Front 42

What makes the reaction catalyzed by citrate synthase highly exergonic?

Back 42

hydrolysis of thioester

Front 43

What type of reaction is the conversion of fumarate to malate?

Back 43

hydration

Front 44

When acetyl-CoA reacts with oxaloacetate to form citrate

Back 44

a new carbon-carbon bond is formed

Front 45

Where is succinate dehydrogenase located?

Back 45

Correct mitochondrial inner membrane

Front 46

Which 5-carbon intermediate of the citric acid cycle is converted to a 4-carbon molecule with the release of carbon dioxide?

Back 46

ketoglutarate

Front 47

Which enzyme catalyzes the conversion of citrate to isocitrate?

Back 47

aconitase

Front 48

Which enzyme catalyzes the reaction shown?

Back 48

malate dehydrogenase

Front 49

Which enzyme catalyzes the reaction shown?

Back 49

succinate dehydrogenase

Front 50

Which enzyme catalyzes the reaction shown?

Back 50

succinyl-CoA synthetase

Front 51

Which enzymes in the citric acid cycle catalyze oxidative decarboxylation reactions?

Back 51

isocitrate dehydrogenase and the α-ketoglutarate dehydrogenase complex

Front 52

Which group of small molecules best fit the boxes associated with the reaction shown?

Back 52

Group 2

Front 53

Which group of small molecules best fit the boxes associated with the reaction shown?

Back 53

Group Five

Front 54

Which of the following causes pyruvate dehydrogenase kinase to catalyze the phosphorylation and inactivation of E1 in the pyruvate dehydrogenase complex?

Back 54

elevated concentrations of NADH and ATP

Front 55

Which of the following coenzymes is required by E1 of the pyruvate dehydrogenase complex for catalytic activity?

Back 55

thiamine pyrophosphate

Front 56

Which of the following coenzymes is required by the pyruvate dehydrogenase complex for reoxidation of E3?

Back 56

NAD+

NAD+

Front 57

Which of the following condenses with oxaloacetate to form citrate?

Back 57

acetyl-CoA

Front 58

Which of the following enzymes contains an FAD prosthetic group?

Back 58

succinate dehydrogenase

Front 59

Which of the following enzymes does not use NAD+ for oxidation?

Back 59

Succinate Dehydrogenase.

Front 60

Which of the following enzymes is not a control point of the citric acid cycle?

Back 60

aconitase

Front 61

Which of the following enzymes is the only membrane-bound enzyme in the citric acid cycle?

Back 61

Succinate Dehydrogenase.

Front 62

Which of the following enzymes uses coenzyme FAD as the electron acceptor?

Back 62

succinate dehydrogenase

Front 63

Which of the following inhibit(s) pyruvate dehydrogenase kinase?

Back 63

pyruvate

Front 64

Which of the following is an inhibitor of pyruvate dehydrogenase?

Back 64

NADH

Front 65

Which of the reactions of the citric acid cycle requires FAD as a coenzyme?

Back 65

Correct the conversion of succinate to fumarate

Front 66

Which reaction below produces GTP in the citric acid cycle?

Back 66

succinyl CoA ---> succinate

Front 67

Which statement about myosin is not true?

Back 67

All of the answers above are true of myosin.

Hint 67

Myosin is a heterohexamer.

Myosin contains two globular heads.

Myosin contains six different polypeptides

Myosin aggregates to form thick filaments

Front 68

Phosphorylation can be used to either inactivate or activate enzymes. This is a key element in the regulation of glucose metabolism. Phosphorylation of glycogen phosphorylase BLANKS it; phosphorylation of glycogen synthase BLANKS it.

Back 68

Phosphorylation can be used to either inactivate or activate enzymes. This is a key element in the regulation of glucose metabolism. Phosphorylation of glycogen phosphorylase activates it; phosphorylation of glycogen synthase inactivates it.

Hint 68

Glycogenlysis See notes (RED)

Front 69

A lipid-soluble cofactor that can diffuse freely in the membrane of the electron transport chain and carry electrons across the membrane is ________.

Back 69

ubiquinone (Q)

Also known as CoA Q

or

CoA Q 10

Hint 69

The ETC

Front 70

A muscle cell from an alligator jaw contains more mitochondria than a wing muscle of a migrating bird such as a goose.

Back 70

False

Front 71

ATP directly provides the energy to transport protons across the inner membrane from the matrix to the inner-membrane space of mitochondria.

Back 71

False

ATP synthase and other integral membrane proteins pass protons from the matrix to the inner membrane.

NEEDS REVIEW

Hint 71

See TCA regulation folder 2 (tca regulation lecture 2)

Front 72

ATP synthase is located in the ________ of the mitochondrion.

Back 72

inner membrane

Front 73

An important difference between respiratory inhibitors and uncouplers is that

Back 73

uncouplers do not inhibit electron transport whereas respiratory inhibitors do so

Front 74

Another name for Complex I in the mitochondria is

Back 74

NADH-CoQ oxidoreductase.

Hint 74

See TCA regulation folder 2 lecture 2

Front 75

Another name for Complex II in the electron transport chain is

Back 75

succinate-CoQ oxidoreductase.

Front 76

At one time the uncoupler 2,4-dinitrophenol was used as a weight reducing drug. Its side-effects, including death, resulted in its discontinued use. How could this drug cause weight loss?

Back 76

The uncoupler allows the oxidation of fats from adipose tissue without the production of ATP. This allows the oxidation to proceed continuously and use up the fats

Front 77

Compare the pH of the mitochondrial matrix and the inner membrane space.

Back 77

The pH is lower in the inner membrane space.

Front 78

Dehydrogenase Enzymes

Back 78

Primary regulators in the Tricarboxylic Acid Cycle

Hint 78

See TCA cycle google drive pg 1-4 TCA cycle lecture 1

Front 79

Complex 1 of the electron transport chain oxidizes ____, reduces ____, and ____ protons in the process.

Back 79

Complex I of the electron transport chain oxidizes NADH, reduces Coenzyme Q , and pumps protons in the process.

complex 1

oxidises NADH producing NAD+

Reduces coenzyme Q ( transfers 2 electrons/protons)

Moves 4 protons into the intermembrane space from the matrix

Front 80

Complex II in the electron transport chain supplies electrons as ________ to the rest of the chain (complexes III and IV).

Back 80

QH2

Hint 80

See ETC TCA regulation folder 2 lecture 2

Front 81

Complex II of the electron transport chain oxidizes ____, reduces ____, and ____ protons in the process.

Back 81

Complex II of the electron transport chain oxidizes FADH2, reduces coenzyme Q, and does not move protons in the process.

Complex 2 (succinate Dehydrogenase)

oxidises FADH2 producing FAD

Hint 81

See folder 2 TCA lecture

Front 82

Complex III of the electron transport chain oxidizes ____, reduces ____, and ____ protons in the process.

Back 82

Complex III of the electron transport chain oxidizes coenzyme Q, reduces cytochrome C, and pumps protons in the process.

pumps 2 protons

Hint 82

See TCA Regulation folder 2 lecture 2

Front 83

Complex IV of the electron transport chain oxidizes ____, reduces ____, and ____ protons in the process.

Back 83

Complex IV of the electron transport chain oxidizes cytochrome c, reduces O2, and pumps protons in the process.

Front 84

Conformation changes in proteins are crucial in the synthesis of ATP in the mitochondria.

Back 84

True

Front 85

Consider the following half-reactions

Back 85

+1.130 V

Hint 85

See TCA Regulation folder 2 Redox electrical potential lecture

Front 86

Electrons from FADH2 are delivered to ____ and electrons from NADH are delivered to ____ of the electron transport chain.

Back 86

Electrons from FADH2 are delivered to complex 2 and electrons from NADH are delivered to complex 1 of the electron transport chain.

Front 87

Epinephrine can stimulate glycogen degradation while at the same time, lowering glycogen synthesis.

Back 87

True

Front 88

For eukaryotes, where are the Complexes of electron transport located?

Back 88

inner mitochondrial membrane

Front 89

Glucagon is excreted when blood glucose is ________ (high, low), while insulin is secreted when blood glucose is ________ (high, low).

Back 89

Glucagon is excreted when blood glucose is low, while insulin is secreted when blood glucose is high.

Front 90

Glycogen is mainly found in

Back 90

liver and muscle

Front 91

Glycogen phosphorylase and glycogen synthase

Back 91

are not activated simultaneously

Front 92

Glycogen storage occurs in _____ and _____ tissue.

Back 92

Glycogen storage occurs in muscle and liver tissue.

Front 93

Glycogen synthase and glycogen phosphorylase

Back 93

are modified by the same enzymes

Front 94

Glycogen synthesis in vertebrates requires ________ to activate glucose 1-phosphate.

Back 94

Glycogen synthesis in vertebrates requires UTP to activate glucose 1-phosphate.

Front 95

Heat can be generated in the brown adipose tissue of hibernating mammals due to ________.

Back 95

uncoupling by thermogenin

Front 96

How are the branches in glycogen produced?

Back 96

A branching enzyme moves a short chain of several glucose units from a linear α(1,4) section of glycogen to make a new α(1,6) branch point.

Front 97

How do uncoupling agents affect the electron transport chain and oxidative phosphorylation?

Back 97

They provide an alternative path for protons to re-enter the mitochondrial matrix, so ATP synthesis decreases. Electron flow and proton pumping are not affected.

Hint 97

UCPS

UCP4

find lecture

Front 98

How many electrons are required for the complete reduction of one molecule of oxygen gas?

Back 98

four

Hint 98

See TCA regulation folder 2 page 2

Front 99

How many protons are translocated across the membrane by complex I for every pair of electrons that are passed from NADH to QH2?

Back 99

4

Front 100

Hydrolysis of pyrophosphate is an important energy driving force in the synthesis of glycogen.

Back 100

True

Front 101

If an inhibitor disrupts the flow of protons from the matrix into the intermembrane space of mitochondria, no ATP will be formed.

Back 101

True

Front 102

If the ΔG for the oxidation of NADH by oxygen is -220 kJ/mol and the ΔG for transport of H+ across the inner membrane is 20 kJ/mol, what is the efficiency for energy captured in the proton gradient versus energy evolved from NADH oxidation?

Back 102

91%

Front 103

If the following half-reactions are combined, what is the potential for the spontaneous reaction?

Back 103

0.149 V

Front 104

If the reduction potential for NAD+ is -0.315 V and the reduction potential for oxygen is 0.815 V, what is the potential for the oxidation of NADH by ox

Back 104

1.13 V

Front 105

In addition to control of activity by phosphorylation, phosphorylase kinase is activated by

Back 105

Ca2+.

Front 106

In glycogen synthesis, the intermediate between glucose-1-phosphate and glycogen is

Back 106

UDP–glucose.

Hint 106

see glycgogenesis page 2 glycogenesis lecture

Front 107

In glycogen synthesis, what is the intermediate between glucose-1-phosphate and glycogen?

Back 107

UDP-glucose

Front 108

In mammals the enzyme complexes of oxidative phosphorylation are in the inner mitochondrial matrix.

Back 108

False

Front 109

In the electron transport chain, electrons are passed from redox center to redox center ____.

Back 109

spontaneously due to the redox potential gradient.

Front 110

In the presence of an uncoupler, more substrate can be oxidized.

Back 110

True

Front 111

In the presence of oxygen and in the absence of ADP, what occurs if the uncoupler 2,4-dinitrophenol is added to a suspension of normal mitochondria five minutes after an oxidizable substrate has been added?

Back 111

Oxidation of the substrate does not occur until the 2,4-dinitrophenol is added. Afterward, oxidation proceeds rapidly until all of the substrate is consumed.

Front 112

Mitochondria are about the size of an E. coli cell.

Back 112

True

Front 113

Oxidative phosphorylation occurs in the mitochondrial membrane in eukaryotes and the plasma membrane in bacteria.

Back 113

True

Front 114

Oxidative phosphorylation requires all of the items listed below except

Back 114

a matrix more positively charged than the intermembrane space.

Front 115

Phosphate (Pi) is transported into the mitochondria from the cytosol by a phosphate carrier which is driven by the

Back 115

simultaneous transport of H+ into the mitochondrion

Front 116

Phosphoprotein phosphatase -1 (PP1)

Back 116

catalyzes the dephosphorylation of phosphorylase kinase.catalyzes the dephosphorylation of glycogen phosphorylase.

Front 117

Protein kinase A, which stimulates glycogen degradation, is activated directly by

Back 117

cyclic AMP. or CAMP

Front 118

Respiratory inhibitors in mitochondria do this:

Back 118

Block both electron flow and ATP synthesis

Front 119

Since caffeine inhibits cAMP phosphodiesterase, too much coffee can result in the synthesis of too much glycogen.

Back 119

False

Front 120

The ________ is between the inner and outer membranes of the mitochondria.

Back 120

The intermembrane space is between the inner and outer membranes of the mitochondria.

Front 121

The compound uridine diphosphate glucose (UDPG) plays a role in

Back 121

glycogen synthesis.

Front 122

The cytochromes undergo which of the following oxidation reactions?

Back 122

Fe2+ → Fe3+

Front 123

The enzyme complexes I-IV in the electron transport chain associate with each other by a combination of hydrophobic interactions, disulfide bridges and hydrogen bonding

Back 123

False

Front 124

The enzyme glycogen phosphorylase catalyzes a reaction in

Back 124

glycogen breakdown.

Front 125

The final reduced species in the electron transport chain is

Back 125

H2O

Front 126

The main enzyme of glycogen catabolism is _____, which catalyzes a _____ reaction.

Back 126

The main enzyme of glycogen catabolism is glycogen phosphorylase, which catalyzes a phosphorolysis reaction.

Front 127

The number of mitochondria per cell is relatively constant among cell types and species

Back 127

False

Front 128

The numbers of mitochondria in cells is closely associated with cell function

Back 128

True

Front 129

The only complex which actually uses molecular oxygen is

Back 129

Complex IV

Front 130

The oxidation of FADH2 to FAD involves the transfer of _____; the oxidation of NADH to NAD+ involves the transfer of _____.

Back 130

The oxidation of FADH2 to FAD involves the transfer of two hydrogen atoms; the oxidation of NADH to NAD+ involves the transfer of a hydride.

Front 131

The proton motive force is a result of

Back 131

a combination of an electrical potential and a chemical potential

Front 132

The protonmotive force is the free energy due to the proton gradient across the inner mitochondrial membrane.

Back 132

True

Front 133

The reduction potential (E°) is numerically related to the value of ΔG.

Back 133

True

Front 134

The source of energy to produce ATP in mitochondria is a proton gradient formed across the outer mitochondrial membrane.

Back 134

false (WRONG)

In the ECT (oxidative phosphorylation)

The Proton gradient provides the enrgy needed to convert ADP to ATP via ATP synthase (molecular motor) by converting electrical potential into kinetic energy

Front 135

The synthesis of ATP in mitochondria is driven by a proton or pH gradient.

Back 135

True

Front 136

The terminal electron acceptor for complex III of the electron transport chain is

Back 136

Cytochome C

Front 137

The ultimate electron acceptor from complex II is

Back 137

Q (ubiquinone)

Front 138

The ultimate electron acceptor in the electron transport chain is

Back 138

oxygen.

Front 139

UDP-glucose pyrophosphorylase works by this mechanism:

Back 139

It adds a UMP molecule to glucose-1-phosphate by splitting out pyrophosphate.

Front 140

Uncouplers are compounds that inhibit the phosphorylation of ADP

Back 140

without affecting electron transport.

Front 141

Uncoupling agents can work by disrupting the flow of protons during ATP synthesis.

Back 141

True

Front 142

Uncoupling in mitochondria refers to:

Back 142

Stopping ATP synthesis but not stopping electron flow.

Front 143

Under starvation conditions, about how long does it take in humans for the body to deplete the glycogen store in the liver?

Back 143

24 hours

Front 144

What does the reduction potential of 0.815 V for the reduction of water to oxygen indicate?

Back 144

oxygen is a very strong oxidizing agent

Front 145

What feature of cytochromes makes them valuable in electron transport systems?

Back 145

the iron ion

Front 146

What is the driving force for the reaction catalyzed by UDP-glucose pyrophosphorylase that converts glucose 1-phosphate to UDP-glucose?

Back 146

the subsequent hydrolysis of pyrophosphate

Front 147

What kind of reaction is used to release glucose units from glycogen?

Back 147

phosphorolysis

Front 148

What shuttle mechanism transfers cytosolic NADH into the mitochondria with a loss of reductive power, with the electrons entering the electron transport chain as ubiquinol instead of NADH?

Back 148

glycerol-3-phosphate shuttle

Front 149

When glycogen phosphorylase is phosphorylated

Back 149

its activity increases.

Front 150

When glycogen synthase is phosphorylated

Back 150

its activity decreases.

Front 151

When mitochondria are actively carrying out aerobic respiration

Back 151

the pH of the matrix is greater than the pH of the intermembrane space.

Front 152

Which complex contains cytochrome oxidase?

Back 152

Complex IV

Front 153

Which complex contains succinate dehydrogenase?

Back 153

Complex II

Front 154

Which complex in the electron transport chain carries electrons from cytochrome c to molecular oxygen, reducing it to water?

Back 154

IV

Front 155

Which complex in the electron transport chain does not contribute to the proton gradient?

Back 155

II

Front 156

Which enzyme cleaves the α(1 → 6) bonds in glycogen?

Back 156

debranching enzyme

Front 157

Which has the highest reduction potential?

Back 157

O2

Front 158

Which of the following aides in formation of a primer for glycogen synthesis?

Back 158

glycogenin

Front 159

Which of the following are located in the inner mitochondrial membrane?

Back 159

all the components of the electron transport chain and one of the components of the citric acid cycle, namely the succinate dehydrogenase complex

Front 160

Which of the following best describes how liver supplies other tissues with the glucose it releases from its stored glycogen?

Back 160

It releases glucose into the blood.

Front 161

Which of the following complexes does not directly contribute to the production of ATP by pumping protons?

Back 161

Complex II.

Front 162

Which of the following correctly relates the order of intermediates during the synthesis of glycogen?

Back 162

glucose → glucose-6-phosphate → glucose-1-phosphate → UDP-glucose → glycogen

Front 163

Which of the following describes a sequence which will ultimately activate glycogen breakdown in a muscle?

Back 163

epinephrine binds β receptors. cAMP PKA phosphorylase kinase glycogen phosphorylase

Front 164

Which of the following enzymes catalyzes the conversion of glucose-1-phosphate to glucose-6-phosphate?

Back 164

phosphoglucomutase

Front 165

Which of the following enzymes catalyzes the conversion of glucose-1-phosphate to glucose-6-phosphate?

Back 165

phosphoglucomutase

Front 166

Which of the following transport mechanisms is used in the inner mitochondrial membrane? IMS = intermembrane space

Back 166

symport of Pi and H+ from IMS to matrix

Front 167

Which of the following will NOT activate glycogen phosphorylase in the liver?

Back 167

eating a high carbohydrate meal

Front 168

Which statement is TRUE concerning the metabolic reaction shown below?

Back 168

The enzyme that catalyzes this reaction is called a mutase.

Front 169

Which statement is true about two reactions that are coupled?

Back 169

One reaction will normally not occur without the other.

Front 170

A coenzyme frequently encountered in transamination reactions is

Back 170

pyridoxal phosphate.

Front 171

A special carrier is needed to get fatty acids into the mitochondria, since an acyl-CoA cannot cross the outer mitochondrial membrane.

Back 171

True

Front 172

After consuming a delicious frosted donut, glucose pours into your muscle cells and is oxidized to recharge your cells with ATP. When ATP levels rise to sufficient levels, your muscle cells begin to store glucose as glycogen for later use when you are fasting. Which of the following enzymes is primarily responsible for the storage of glucose as glycogen?

Back 172

Glycogen synthase

Front 173

After digesting a delicious frosted donut, glucose pours into your muscle cells and is oxidized to recharge your cells with ATP. When ATP levels rise to sufficient levels, your muscle cells begin to store glucose as glycogen for later use when you are fasting. Which of the following enzymes is primarily responsible for the switch from ATP production to glycogen storage?

Back 173

Phosphofructokinase-1

Front 174

An individual consumes a large amount of glucose during breakfast. If the individual has normal metabolism, this consumption should result in which of the following conditions?

Back 174

Enhanced glycogen synthase activity in muscle

Front 175

By a simple transamination reaction, intermediates in glycolysis or the Kreb's Cycle can be converted in one step to all of these amino acids, except

Back 175

Serine

Front 176

Carnitine acyltransferase is located in the mitochondrial

Back 176

inner membrane.

Front 177

Considering the figure below, what compound would be formed by action of acyl-CoA dehydrogenase?

Back 177

Front 178

Dihydroxyacetone phosphate (DHAP) is converted to glyceraldehydes-3-phosphate by the enzyme triose isomerase to continue the reactions of glycolysis. The delta-G for this reaction is +0.6 making it readily reversible. Under what circumstances would you want to reverse this reaction?

Back 178

To transfer electrons from cytosolic NADH to FAD by glycerol-3-phosphate in the inner mitochondrial membrane.

Front 179

Each round of β-oxidation of a saturated fatty acyl-CoA produces _____.

Back 179

1 NADH, 1 QH2, 1 acetyl-CoA

Front 180

Fatty acid catabolism is called β-oxidation, since the second or β carbon from the carboxyl group is the site of oxidation.

Back 180

True

Front 181

Fatty acids are oxidized in the

Back 181

mitochondrial matrix

Front 182

Glycogen synthesis and catabolism begin and end, respectively, with glucose-6-phosphate. Which of the following enzymes is required for both synthesis and catabolism of glycogen?

Back 182

Phosphoglucomutase

Front 183

How many NAD+ are reduced in the degradation of palmitoyl-CoA to form eight molecules of acetyl-CoA?

Back 183

7

Front 184

How many QH2 and NADH are produced by one round of the -oxidation pathway?

Back 184

1 each

Front 185

How many cycles of -oxidation are required to completely process a saturated C18 fatty acid?

Back 185

8

Front 186

If the carbonyl carbon of a fatty acyl CoA molecule with a C10 chain is labeled with 14C, how many rounds of -oxidation are required to produce a radioactively labeled acetyl CoA?

Back 186

one

Front 187

In the β-oxidation pathway, the oxidation occurs at carbon _____ with the acetyl group that becomes acetyl-CoA derived from the _____ end of the fatty acid.

Back 187

In the β-oxidation pathway, the oxidation occurs at carbon 3 with the acetyl group that becomes acetyl-CoA derived from the carbonyl end of the fatty acid.

Front 188

Long-chain fatty acids (>16 carbons) are transported into cells using fatty acid transport proteins. After entering the cytosol, reverse transport of the fatty acids is prevented by

Back 188

being conjugated with coenzyme-A through an acyl linkage.

Front 189

Oxidation of 1 mole of the fatty acid 14:1 will generate how many moles of acetyl CoA?

Back 189

7

Front 190

Oxidation of 1 mole of the fatty acid C18:1Δ6 will generate how many moles of acetyl CoA?

Back 190

9

Front 191

Palmitic acid, with 16 carbons, requires 8 cycles of β-oxidation to produce 8 acetyl-CoA.

Back 191

False

Front 192

Polymerization of glucose by glycogen synthase to form glycogen occurs through

Back 192

energy contributed by hydrolysis of UDP-glucose.

Front 193

The carrier molecule which transports fatty acids through the inner mitochondrial membrane is

Back 193

Carnitine

Front 194

The enzyme activity catalyzing the reaction shown is best termed a

Back 194

dehydrogenase

Front 195

The first three reactions of the β-oxidation cycle of fatty acids produce

Back 195

one mole each of NADH and FADH2

Front 196

The oxidation of fatty acids is best described by which of the following sets of reactions?

Back 196

Oxidation, hydration, oxidation, carbon-carbon bond breaking

Front 197

The processing of one molecule of stearic acid (18 carbons) by β-oxidation

Back 197

requires 8 cycles of β-oxidation and produces 9 molecules of acetyl-CoA.

Front 198

The reactions involved in β-oxidation of fatty acids include the following:

Back 198

3 → 2 → 4 → 1

Front 199

There are four steps in the -oxidation pathway. Some reaction types are listed below. Give the proper reaction types in the order that they occur in the -oxidation pathway.

Back 199

2, 5, 2, 4

Front 200

Transport of free fatty acids from the cytoplasm to the mitochondrial matrix requires

Back 200

ATP, carnitine, coenzyme A.

Front 201

Two critical hormones that signal for glycogen breakdown are:

Back 201

glucagon and epinephrine.

Front 202

What amino acid is attached to the pyridoxal-5′-phosphate in a typical transaminase?

Back 202

Lys

Front 203

What are the β-oxidation products of stearic acid, a saturated fatty acid with 18 carbons?

Back 203

8 NADH, 8 QH2, 9 acetyl-CoA

Front 204

What are the products of the following transamination reaction?

Back 204

glutamate; pyruvate

Front 205

What is the product of fatty acid activation?

Back 205

acyl-CoA

Front 206

What transport system moves activated fatty acids from the cytosol to the mitochondrial matrix?

Back 206

carnitine shuttle

Front 207

What type of reaction is used to deaminate most amino acids?

Back 207

transamination

Front 208

When amino acids are catabolized for use in energy producing pathways, which of the following reactions must occur first for the majority of amino acids?

Back 208

Transmination reaction requiring pyridoxal phosphate

Front 209

Where in the cell does β-oxidation occur?

Back 209

Mitochondrial matrix.

Front 210

Which group of small molecules best fit the boxes associated with the reaction shown?

Back 210

II

Front 211

Which lipid form is transported across the inner mitochondrial membrane before -oxidation?

Back 211

acylcarnitine

Front 212

Which of the following best explains the chain of events that occurs when glucagon binds to its receptor?

Back 212

activation of G protein, activation of adenylate cyclase, production of cAMP, activation of protein kinase A

Front 213

Which of the following citric acid cycle intermediates can be converted to aspartate via transamination?

Back 213

oxaloacetate

Front 214

Which of the following is a true statement for fatty acid oxidation?

Back 214

Both NADH and QH2 are produced.

Front 215

Which of the following is not an advantage of fatty acids as a form of energy storage?

Back 215

Storage of fats in muscle tissue makes it readily available for use during activity.

Front 216

Which of the following statements concerning β-oxidation of fatty acids is false?

Back 216

Initiation occurs at the methyl end of the fatty acid.

Front 217

Why is it undesirable to have high concentrations of free fatty acids in cells?

Back 217

They are amphipathic and act as detergents that can degrade membranes.