Term 1

ubiquitin

Definition 1

This protein is used as a tag to identify proteins targeted for destruction

Term 2

pepsin

Definition 2

This is the primary proteolytic enzyme of the stomach

Term 3

aminotransferases

Definition 3

These enzymes transfer an alpha-amino group from amino acids to alpha-ketoglutarate
-

Term 4

glutamate dehydrogenase

Definition 4

This enzyme catalyzes an oxidative deamination and can utilize either NAD+ or NADP+.

Term 5

Schiff-base linkages

Definition 5

This is the type of intermediate that forms between PLP and an amino acid

Term 6

urea

Definition 6

This is the molecule that is formed from excess NH4+ by ureotelic organisms
-

Term 7

oxaloacetate

Definition 7

This product results when aspartate is transaminated with -ketoglutarate

Term 8

S-adenosylmethionine

Definition 8

This methyl group donor is the product of the first step of methionine degradation

Term 9

dioxygenases

Definition 9

This class of enzymes cleave most aromatic rings in biological systems
-

Term 10

biopterin

Definition 10

This is the cofactor required by phenylalanine hydroxylase

Term 11

lysine

Definition 11

The C-terminal glycine of ubiquitin is covalently linked to ________________ residues of the protein destined to be degraded.

Term 12

proteasome

Definition 12

Ubiquitin-tagged proteins are digested by the __________________.
-

Term 13

pyridoxamine phosphate

Definition 13

In the transaminase reaction, pyridoxal phosphate is converted into __________________ when the first amino acid is converted into an -keto acid.

Term 14

urea

Definition 14

The hydrolysis of arginine by arginase produces ornithine and ______________.

Term 15

alanine/glutamine

Definition 15

Nitrogen is transported from muscle to liver in the form of ______________.
-

Term 16

vitamine B6 or pyridoxine

Definition 16

The vitamin that plays a key role in amino acid degradation is ________________.

Term 17

pyruvate

Definition 17

Serine dehydratase catalyzes the conversion of serine into NH4+ and __________________.

Term 18

glutamate

Definition 18

In the degradation of amino acids, the amino nitrogens can eventually become the amino group of ___________________.
-

Term 19

carbamoyl phosphate

Definition 19

In the first step of the urea cycle, CO2 and NH4+ are converted into __________________.

Term 20

branched chain alpha-keto acid dehydrogenase

Definition 20

The genetic deficiency of the enzyme __________________________ results in a condition referred to as maple syrup urine disease

Term 21

Surplus amino acids are

Definition 21

used as metabolic fuel
-

Term 22

N-acetylglutamate

Definition 22

Which of the following is an allosteric activator of mammalian carbamoyl-phosphate synthetase?

Term 23

amino terminal residue

Definition 23

The half-life of a cytosolic protein is primarily determined by the

Term 24

aspartate

Definition 24

In the urea cycle, the second nitrogen of urea enters the cycle in the form of which of the following metabolites?
-

Term 25

a system for coenzyme biosynthesis

Definition 25

The eukaryotic system for ubiquitination appears to have evolved from what prokaryotic precursor?

Term 26

serine and threonine

Definition 26

Which amino acids can be directly deaminated to produce NH4+?

Term 27

carbamic acid

Definition 27

In the urea cycle, free NH4+ is coupled with carboxyphosphate to form ______________.
-

Term 28

ornithine and citrilline

Definition 28

Which amino acid(s) are metabolites in the urea cycle, but are not used as building blocks of proteins?

Term 29

fumarate

Definition 29

In the urea cycle, the carbon skeleton of aspartate is preserved as

Term 30

nucleotide biosynthesis

Definition 30

Four of the five enzymes in the urea cycle are evolutionarily related to enzymes found in
-

Term 31

NH4+

Definition 31

Ammoniotelic organisms excrete excess nitrogen as

Term 32

uric acid

Definition 32

Uricotelic organisms release nitrogen as

Term 33

acetyl-CoA and acetoacetate

Definition 33

Ketogenic amino acids are degraded to which of the following metabolites?
-

Term 34

Met,Ile,Val

Definition 34

Which amino acids supply carbons for eventual entry into metabolism as succinyl CoA?

Term 35

phenylalanine

Definition 35

Which amino acid(s) is (are) converted to tyrosine in the degradative pathway?

Term 36

stable ring structure and monosaccharides formed under prebiotic conditions

Definition 36

Which of the following are reasons that glucose is a common metabolic fuel used by living organisms?
-

Term 37

trap glucose in the cell and destabilize glucose and facilitate the next series of metabolic steps

Definition 37

What is the purpose of phosphorylating glucose in cytosol?

Term 38

glyceraldehyde-3-phosphate and dihydroxyacetone phosphate

Definition 38

What two 3-carbon molecules are generated by the cleavage of fructose-1,6-bisphosphate?

Term 39

binding of substrate induces cleft closing

Definition 39

What is a common mechanistic feature of kinases?
-

Term 40

reversible cleavage of F-1,6-BP to DHAP and GAP

Definition 40

What reaction is catalyzed by aldolase?

Term 41

oxidation by NAD+ and formation of acyl-phosphate

Definition 41

What is the function of glyceraldehyde 3-phosphate dehydrogenase?

Term 42

thioester allows the two-step reaction to be coupled so the second reaction, the energetically unfavorable phosphorylation, can proceed

Definition 42

What is the function of a thioester intermediate such as the one formed from GAP?
-

Term 43

ATP synthesis when the phosphate donor is a substrate with high phosphoryl transfer potential

Definition 43

What is substrate level phosphorylation?

Term 44

2,3-bisphosphoglycerate

Definition 44

What is the additional metabolite that is required for the conversion of 3-phosphoglycerate to 2-phosphoglycerate?

Term 45

ethanol, lactate, acetyl CoA

Definition 45

What are the primary metabolic fates of pyruvate?
-

Term 46

fructose is converted to fructose-6-phosphate

Definition 46

Fructose can enter glycolysis at two distinct points, depending on the tissue. How is fructose metabolized in adipose tissue?

Term 47

lactase

Definition 47

Lactose intolerance is caused by a deficiency of

Term 48

transcriptional control, reversible phosphorylation, allosteric control

Definition 48

How are the glycolytic enzymes regulated?
-

Term 49

lactate and alanine

Definition 49

The primary raw materials for gluconeogenesis are

Term 50

six

Definition 50

How many high-energy phosphate bonds are expended in gluconeogenesis?

Term 51

Krebs cycle and tricarboxylic acid cycle

Definition 51

The citric acid cycle is also known as the
-

Term 52

acetyl CoA

Definition 52

What molecule initiates the citric acid cycle by reacting with oxaloacetate?

Term 53

pyruvate dehydrogenase complex

Definition 53

What enzyme(s) is (are) responsible for the following reaction?

Term 54

decarboxylation, oxidation, transfer to CoA

Definition 54

What are the steps involved (in order) in the conversion of pyruvate to acetyl CoA?
-

Term 55

thiamine, riboflavin, niacin, lipoic acid, and pantothenic acid

Definition 55

Which of the following vitamins are precursors to coenzymes that are necessary for the formation of acetyl CoA from pyruvate?

Term 56

lipoamide

Definition 56

Which of the following functions as a “flexible swinging arm” when it transfers the reaction intermediate from one active site to the next?

Term 57

condensation

Definition 57

Formation of citrate from acetyl CoA and oxaloacetate is a(n) _________ reaction
-

Term 58

dehydration followed by hydration

Definition 58

What is/are the chemical change(s) involved in the conversion of citrate into isocitrate?

Term 59

conversion of succinyl CoA to succinate

Definition 59

In which reaction is GTP (or ATP) directly formed in the citric acid cycle?

Term 60

the conversion of succinate to fumarate

Definition 60

In which step of the citric acid cycle is FADH2 formed?
-

Term 61

elevated concentrations of NADH and ATP

Definition 61

Which of the following conditions will activate pyruvate dehydrogenase kinase which catalyzes the phorphorylation and inactivation of E1 in the pyruvate dehydrogenase complex?

Term 62

ten

Definition 62

Approximately how many ATP or GTP equivalents are produced during one turn of the citric acid cycle?

Term 63

isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, citrate synthase (in bacteria)

Definition 63

In addition to pyruvate dehydrogenase, what other enzymes are key regulatory sites in the citric acid cycle?
-

Term 64

acetate

Definition 64

The glyoxylate cycle enables plants to survive using only

Term 65

proton

Definition 65

What type of gradient is critical to ATP formation by oxidative phosphorylation?

Term 66

26 out of 30

Definition 66

When glucose is totally oxidized to CO2 and H2O, how many ATP molecules are made by oxidative phosphorylation relative to the maximum yield?
-

Term 67

oligomycin blocks the proton transfer through Fo of ATP synthase and therefore blocks the phosphorylation of ADP to form ATP

Definition 67

What is the chemical effect of oligomycin on aerobic metabolism?

Term 68

NADH -> complex I -> CoQ -> Complex III -> Cyt c -> complex IV -> O2
FADH2 -> complex II -> CoQ -> Complex III -> Cyt c -> complex IV -> O2

Definition 68

Choose the correct path taken by a pair of electrons as it travels down the electron-transport chain.

Term 69

coenzyme A

Definition 69

Which of the following does not participate in, nor is a component of, the electron-transport chain?
-

Term 70

cytoplasmic membrane

Definition 70

In prokaryotes the site of ATP-synthesizing machinery is

Term 71

transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space

Definition 71

Electron flow down the electron-transport chain leads to the

Term 72

ubiquinone

Definition 72

Coenzyme Q is also called
-

Term 73

Complex II

Definition 73

Which of the following does not pump protons?

Term 74

Cys

Definition 74

In proteins these amino acid residues usually complex to the iron-sulfur clusters.

Term 75

a protein that transfers electrons, and that also contains a heme prosthetic group

Definition 75

What is a cytochrome?
-

Term 76

His

Definition 76

In the Rieske center, the iron-sulfur center is coordinated to the amino acid(s) _______

Term 77

ADP3 + HPO42- + H+ <-> ATP4- + H2O

Definition 77

What is the reaction of ATP synthase?

Term 78

1.5

Definition 78

What is the net ATP obtained from one cytoplasmic NADH when it is reoxidized by the electron-transport chain using the glycerol 3-phosphate shuttle?
-

Term 79

oxaloacetate

Definition 79

In the malate-aspartate shuttle, electrons from NADH are transferred to ________, forming malate.

Term 80

liver and skeletal muscle

Definition 80

The major site(s) of glycogen storage is (are)

Term 81

glycogen phosphorylase

Definition 81

The key enzyme in glycogen degradation is
-

Term 82

transferase and alpha-1,6-glucosidase

Definition 82

What enzyme(s) is (are) required to cleave alpha-1,6-glycosidic branches in glycogen?

Term 83

phosphoglucomutase

Definition 83

Conversion of glucose 1-phosphate to glucose 6-phosphate is carried out by the enzyme

Term 84

water

Definition 84

What molecule must be excluded from the active site of glycogen phosphorylase?
-

Term 85

addition of a phosphate to a serine residue

Definition 85

How is phosphorylase b converted into phosphorylase a?

Term 86

active site is partially blocked

Definition 86

Why is the T state of glycogen phosphorylase less active?

Term 87

high ATP and high glucose 6-phosphate levels

Definition 87

What physiological conditions render phosphorylase b less active?
-

Term 88

for glucose export to other tissues when glucose levels are low

Definition 88

What is the function of liver glycogen degradation?

Term 89

Ca2+, cAMP activated PKA (Protein Kinase A)

Definition 89

Phosphorylase kinase is regulated by

Term 90

glucagon and epinephrine

Definition 90

Two critical hormones that signal for glycogen breakdown are
-

Term 91

glycogen synthase

Definition 91

The key regulatory enzyme in glycogen synthesis is

Term 92

branching increases the solubility of glycogen and glycogen synthesis and degradation by increasing the potential sites of action

Definition 92

Why is glycogen branching important?

Term 93

blood-glucose levels increase leading to glycogen storage in the liver

Definition 93

Which of the following occur after a carbohydrate-rich meal?
-

Term 94

80-120 mg/100 mL (4.4-6.7 mM)

Definition 94

What is the normal glucose concentration in blood?

Term 95

NADPH

Definition 95

ATP is called the energy currency. The currency of reducing power is

Term 96

CO2

Definition 96

What is the source of carbons for the Calvin cycle?
-

Term 97

radioactive tracer experiments using 14CO2

Definition 97

What experiments led to the proof that carbon dioxide was incorporated into 3-phosphoglycerate?

Term 98

G-1-P, G-6-P, F-6-P

Definition 98

In the Calvin cycle, 3-phosphoglycerate is converted into which hexose phosphate?

Term 99

ribose 5-phosphate and xyulose 5-phosphate

Definition 99

Which sugar(s) is (are) converted into ribulose 5-phosphate by a single enzymatic step?
-

Term 100

reduced

Definition 100

Which form of thioredoxin activates certain Calvin cycle enzymes?

Term 101

NADPH

Definition 101

Which coenzyme is required by glyceraldehyde 3-phosphate dehydrogenase in chloroplasts to convert 3-phosphoglycerate into glyceraldehyde-3-phosphate?

Term 102

at high temperatures, the oxygenase activity of rubisco is high

Definition 102

The C4 pathway is necessary in tropical plants because
-

Term 103

30 molecules of ATP are used per hexose molecule made

Definition 103

What is the energy cost of the C4 pathway?

Term 104

generate NADPH and synthesize 5-carbon sugars

Definition 104

The purpose of the pentose phosphate pathway is to

Term 105

a thousand times lower than

Definition 105

The KM of glucose 6-phosphate dehydrogenase for NADP+ is _____________ the KM for
NAD+
-

Term 106

C5 + C6 <-transketolase-> C2 + C9

Definition 106

Which of the following reactions is not part of the pentose phosphate pathway?

Term 107

3 C5 <-> 2 C6 + C3

Definition 107

What is the net reaction of the transketolase and transaldolase steps?

Term 108

skeletal muscle

Definition 108

Which of the following tissues do not contain the enzymes for an active pentose-phosphate
pathway?
-

Term 109

FAD

Definition 109

Which cofactor is required by glutathione reductase to aid in the reduction of oxidized
glutathione by NADPH?

Term 110

phospholipids and glycolipids

Definition 110

Fatty acids are the building blocks of

Term 111

anhydrous and highly reduced

Definition 111

Why are triacylglycerols an excellent design for energy stores?
-

Term 112

lipases

Definition 112

Enzymes that digest the triacylglycerols into free fatty acids and monoacylglycerol are called

Term 113

glucagon; insulin

Definition 113

The hormone __________ induces lipolysis, whereas the hormone __________ inhibits the process.

Term 114

ATP-dependent activation of fatty acids using CoA

Definition 114

The function of the enzyme acyl CoA synthetase is
-

Term 115

FAD and NAD+

Definition 115

Coenzyme(s) involved in the degradation of saturated fatty acyl CoA include(s)

Term 116

7 Acetyl-CoA + 6 FADH2 + 6 NADH + 6 H+

Definition 116

The beta oxidation of myristyl-CoA (C-14:0) yields

Term 117

seven

Definition 117

How many rounds of beta oxidation would be required for a 16-C fatty acyl chain to be degraded to acetyl-CoA?
-

Term 118

intramolecular rearrangements, methylations, reduction of ribonucleotides to deoxyribonucleotides

Definition 118

What types of reactions do cobalamin enzymes catalyze?

Term 119

initial dehydrogenation reaction is different in that electrons are transferred to O2 to yield H2O2

Definition 119

How does beta oxidation differ in peroxisomes?

Term 120

heart muscle, renal cortex

Definition 120

What organs or tissues prefer to use ketone bodies such as acetoacetate as a fuel energy source instead of glucose?
-

Term 121

synthesis of malonyl CoA

Definition 121

What is the committed step in fatty acid synthesis?

Term 122

palmitate + 7 CO2 + 14 NADP+ + 8 CoA + 6 H2O

Definition 122

Complete this reaction:
Acetyl CoA + 7 malonyl CoA + 14 NADPH + 20 H+ ->

Term 123

enzyme is switched off by phosphorylation and activated by dephosphorylation

Definition 123

How is acetyl carboxylase globally regulated?
-

Term 124

by elongation reactions catalyzed by enzymes on the endoplasmic reticulum

Definition 124

How are fatty acids larger than 16 carbons formed?

Term 125

phosphatidate

Definition 125

Which of the following is the common precursor for both the phosphatidyl inositols and triacylglycerols?

Term 126

glycerol 3-phosphate and two fatty acyl-CoA’s

Definition 126

Phosphatidate is formed from
-

Term 127

stearic acid; arachidonic acid

Definition 127

In phosphatidyl inositol, __________ and _________ usually occupy the C-1 position and the C-2 position, respectively

Term 128

central nervous system

Definition 128

The highest concentration of sphingolipids is found in the

Term 129

palmitoyl CoA and serine

Definition 129

The starting materials necessary to synthesize sphingosine are
-

Term 130

cholesteryl linoleate

Definition 130

Which of the following is the major component of low-density lipoproteins?

Term 131

dipalmitoyl phosphatidyl choline

Definition 131

Respiratory distress syndrome is caused by a failure in the biosynthetic pathway of

Term 132

gangliosides

Definition 132

Tay Sachs disease is caused by an inability to degrade
-

Term 133

acetoacetyl CoA

Definition 133

HMG CoA is synthesized from acetyl CoA and

Term 134

3-hydroxy-3-methylglutaryl CoA reductase

Definition 134

Feedback regulation of cholesterol synthesis is mainly controlled at the step catalyzed by the enzyme

Term 135

solubilize hydrophobic lipids and contain cell-targeting signals

Definition 135

The role of lipoprotein particles is to
-

Term 136

chylomicrons

Definition 136

The major carrier(s) of dietary fat from the intestine is (are)

Term 137

clathrin

Definition 137

The LDL receptors on the plasma membrane are localized in coated pits that contain the receptors of which of the following proteins?

Term 138

glycine

Definition 138

Which of the following combines with cholic acid to form a major bile salt?
-

Term 139

NADPH and activated O2

Definition 139

Hydroxylation of cholesterol by cytochrome P450 requires

Term 140

pyruvate -> acetyl-CoA + CO2
alpha-ketoglutarate -> succinyl-CoA + CO2

Definition 140

Excess alcohol consumption can lead to Wernicke-Korsaff syndrome due to the lack of the vitamin thiamine. Which of the following metabolic conversions cannot occur in the absence of thiamine?

Term 141

NADPH

Definition 141

The major electron donor in reductive biosynthesis is
-

Term 142

phosphofructokinase

Definition 142

An important regulatory enzyme in glycolysis is

Term 143

degrading glucose to provide ATP and providing carbon skeletons for biosynthesis

Definition 143

The function(s) of glycolysis include(s)

Term 144

rate of the citric acid cycle matches the need for ATP

Definition 144

What does respiratory control ensure?
-

Term 145

glycogen, pyruvate, ribose 5-phosphate

Definition 145

The most common end product(s) of glucose metabolism include(s)

Term 146

G-6-P, alanine, pyruvate, acetoacetate, fatty acids

Definition 146

Acetyl-CoA is derived from

Term 147

transamination to alanine,
carboxylation to oxaloacetate,
reduction to lactate

Definition 147

What are some of the metabolic fates of pyruvate?
-

Term 148

ketone bodies

Definition 148

Which of the following is the fuel used by the brain during starvation?

Term 149

135,000 kcal

Definition 149

In a typical human male, what is the energy content (in kcal) of triacylglycerols stored in adipose tissue?

Term 150

kidney

Definition 150

The ___________ is an important site of gluconeogenesis during starvation
-

Term 151

alpha keto-acids

Definition 151

What is the primary source of energy used by the liver for its own energy requirements?

Term 152

glucose homeostasis

Definition 152

Maintenance of a constant blood-glucose level is called

Term 153

fed; starved

Definition 153

Insulin signals the ______ state, and glucagon signals the _______ state
-

Term 154

creatine phosphate

Definition 154

Which of the following molecules or metabolic conversions provides the maximum rate of ATP production (mmol/sec) for muscle contraction?