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MADI B > Biochem Mend Material > Flashcards

Biochem Mend Material Flashcards

1
Q

Which of the following is not a component of chylomicrons?
a. Apolipoproteins
b. Bile salts
c. Cholesterol
d. Phospholipids
e. Triacylglycerols

A

BILE SALTS

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2
Q

Which of the following types of reactions commonly uses the molecule shown below in catabolic pathways?
a. Activation of bicarbonate for carboxylations
b. Donation of a phosphate to an alcohol
c. Movement of a phosphate from one position to another in the same molecule
d. Removal of an H- from an alcohol
e. Removal of an H+ from an acid

A

REMOVAL OF AN H- FROM AN ALCOHOL

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3
Q

Which of the following is not true of the activity of hexokinase?
a. Creates a high energy bond that can be used to phosphorylate ADP
b. Is inhibited by its own product
c. Prevents fructose-6-phosphate from adopting a pyranose conformation
d. Raises the concentration of glucose-6-phosphate in the cell relative to glucose
e. Traps glucose-6-phosphate within the cell

A

CREATES A HIGH ENERGY BOND THAT CAN BE USED TO PHOSPHORYLATE ADP

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4
Q

Which of the following glycolytic steps are bypassed in gluconeogenesis?
a. 3-phosphoglycerate to 2-phosphoglycerate
b. Dihydroxyacetone-P to glyceraldehyde-3-P
c. Fructose-1,6-bisphosphate to dihydroxyacetone-P + glyceraldehyde-3-P
d. Fructose-6-P + ATP to fructose-1,6-bisphosphate + ADP
e. Glucose-6-P to fructose-6-P

A

FRUCTOSE-6-P + ATP TO FRUCTOSE-1,6-BISPHOSPHATE + ADP

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5
Q

Which of the following is not a product of the pyruvate dehydrogenase complex?
a. Acetyl-CoA
b. ADP
c. CO2
d. H+
e. NADH

A

ADP

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6
Q

The structure shown is generated by fumarate by:
a. Carboxylation
b. Decarboxylation
c. Hydration of a double bond between C2 and C3
d. Oxidation of a carbonyl at C1
e. Reduction of a carbonyl at C2

A

HYDRATION OF A DOUBLE BOND BETWEEN C2 AND C3

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7
Q

In a single redox cycle, a heme group transfers:
a. One electron and no protons
b. One electron and one proton
c. One or two electrons and one or two protons
d. Two electrons and one proton
e. Two electrons and two protons

A

ONE ELECTRON AND NO PROTONS

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8
Q

Where are the two proton half-channels in the F1F0 ATP synthase?
a. F0 a subunit
b. Fo b subunit
c. F0 c subunit
d. F1 alpha subunit
e. F1 beta subunit

A

F0 a subunit

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9
Q

Which of the following is a true statement? Glycogen synthase:
a. Can extend an amylose chain by no more than 20 sugar residues
b. Is inhibited by glucose-6-phosphate
c. Requires a short “seed” of at lease 10-20 a-1,4 linked glucosyl residues as a substrate
d. Uses a glucose-6-phosphate as a substrate
e. Uses a phosphate instead of water to remove glucosyl residues from glycogen

A

REQUIRES A SHORT “SEED” OF AT LEAST 10-20 A-1,4-LINKED GLUCOSYL RESIDUES AS A SUBSTRATE

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10
Q

Which of the following describes the sequence of events that result in the release of an acetyl-CoA unit from a fatty acyl-CoA?
a. Oxidation by FAD to hydration to oxidation by NAD+ to phosphorolysis
b. Oxidation by FAD to hydration to oxidation by NAD+ to thiolysis
c. Oxidation by NAD+ to hydration to oxidation by FAD to hydrolysis
d. Oxidation by NAD+ to hydration to oxidation by FAD to phosphorolysis
e. Oxidation by NAD+ to hydration to oxidation by FAD to thiolysis

A

OXIDATION BY FAD TO HYDRATION TO OXIDATION BY NAD+ TO THIOLYSIS

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11
Q

During fatty acid synthesis, what happens next to the compound shown?
a. Dehydration
b. Dehydrogenation
c. Isomerization
d. Oxidation
e. Reduction

A

DEHYDRATION

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12
Q

The first two steps of cholesterol biosynthesis are also the first two steps of:
a. Fatty acid synthesis
b. Gluconeogenesis
c. Glycolysis
d. Ketone body synthesis
e. Sphingolipid biosynthesis

A

KETONE BODY SYNTHESIS

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13
Q

Which amino acid is oxidatively deaminated to produce the structure shown?
a. Arginine
b. Aspartate
c. Glutamate
d. Lysine
e. Methionine

A

GLUTAMATE

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14
Q

Glutamine is synthesized from active glutamate. How is glutamate activated?
a. By ATP-driven phosphorylation of the alpha-carboxyl
b. By ATP-driven phosphorylation of the side chain carboxyl
c. By the formation of ADP-glutamate
d. By the formation of CDP-glutamate
e. By the formation of UDP-glutamate

A

BY ATP-DRIVEN PHOSPHORYLATION OF THE SIDE CHAIN CARBOXYL

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15
Q

Which of the following statements concerning the de novo synthesis of purine and pyrimidines is false?
a. The de novo synthesis of purines and pyrimidines require 5-phosphoribosyl-1-pyrophosphate (PRPP)
b. The de novo synthesis of purines and pyrimidines assemble the base first and then attach it to the sugar
c. The first step in de novo synthesis of purines is the formation of a N-glycosidic bond
d. The purine ring is assembled from many different components
e. The pentose phosphate pathway provides an essential component for the synthesis of both purines and pyrimidines

A

THE DE NOVO SYNTHESIS OF PURINES AND PYRIMIDINES ASSEMBLE THE BASE FIRST AND THEN ATTACH IT TO THE SUGAR

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16
Q

Cytochrome c is usually found in the:
a. inner mitochondrial membrane
b. mitochondrial intermembrane space
c. mitochondrial matrix
d. outer mitochondrial membrane
e. smooth endoplasmic reticulum

A

MITOCHONDRIAL INTERMEMBRANE SPACE

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17
Q

Which of the following reactions does superoxide dismutase catalyze:
a. 2 H2O2 to 2 OH-
b. 2 H2O2 to O2 + 2 H20
c. 2 H2O2 to OH+ + OH-
d. 2O2- + 2H+ to O2 + 2H2O
e. 2 O2- + 2 H+ to O2 + H2O2

A

2 O2- + 2 H+ to O2 + H2O2

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18
Q

Which of the following mechanisms does brown fat use to raise body temperature?
a. Increases ATP hydrolysis by running the F1F0 ATP synthase in reverse
b. Increases synthesis of dinitrophenol (DNP) which stimulates H+ transport across membranes
c.. Induces futile cycling of glycolysis and gluconeogenesis
d. Secretes of the hormone thermogenin; which induces shivering by muscle cells
e. Uses fatty acids to dissipate the mitochondrial protein gradient

A

USES FATTY ACIDS TO DISSIPATE THE MITOCHONDRIAL PROTEIN GRADIENT

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19
Q

Which of the following are part of a mechanism by which the electrons in the NADH produced during glycolysis enter the electron transport chain?
a. An antiporter that exchanges cytoplasmic NADH for mitochondrial NAD+
b. A symporter that exchanges cytoplasmic NADH for mitochondrial ATP
c. Complex 1-mediated reduction of coenzyme Q to QH2 by cytoplasmic NADH
d. Reduction of cytochrome c by cytoplasmic NADH
e. Reversible reduction of oxaloacetate to malate by cytoplasmic NADH

A

REVERSIBLE REDUCTION OF OXALOACETATE TO MALATE BY CYTOPLASMIC NADH

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20
Q

When carbon monoxide (CO) inhibits complex IV of the electron transport chain, which of the following should you expect to find?
a. High NAD+/NADH ratios in the mitochondrial matrix
b. High Q/QH2 ratios in the inner mitochondrial membrane
c. High FAD/FADH2 ratios in the inner mitochondrial membrane
d. High Fe2+/Fe3+ ratios in cytochrome c
e. High ADP/ATP ratios in the mitochondrial matrix

A

HIGH FE2+/FE3+ RATIOS IN CYTOCHROME C AND HIGH ADP/ATP RATIOS IN THE MITOCHONDRIAL MATRIX

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21
Q

How does pyrophosphatase stimulate the formation of UDP-glucose? Pyrphosphatase:
a. activates glucose by adding a phosphate to carbon 1 of glucose
b. moves a phosphate from carbon 6 to carbon 1 of gluose
c. is a co-factor needed for the catalytic activity of UDP-glucose pyrophosphorylase
d. recycles UDP-glucose pyrophosphorylase back to an active state
e. Removes one of the products of the reaction that forms UDP-glucose from glucose-1-phosphate and UTP

A

REMOVES ONE OF THE PRODUCTS OF THE REACTION THAT FORMS UDP-GLUCOSE FROM GLUCOSE-1-PHOSPHATE AND UTP

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22
Q

Glycogen phosphorylase and a-amylase both act on long glucose polymers linked by a-1,4-glycosidic bonds. Which statement about these enzymes is true.
a. Both enzymes can remove glucosyl units to within one residue of a B-1,6 branch point
b. Both enzymes use water to release glucosyl units
c. Neither enzyme can hydrolyze an a-1,6 glycosidic linkage
d. Neither enzyme requires a free non-reducing end on which to act
e. The liver expresses both enzymes

A

NEITHER ENZYME CAN HYDROLYZE AN A-1,6 GLYCOSIDIC LINKAGE

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23
Q

In the liver, what form will glycogen phosphorylase be in when blood sugar levels are low?
a. R a
b. R b
c. T a
d. T b

A

R a

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24
Q

In the oxidative phase of the pentose phosphate pathway, each glucose molecule typically generates how many NADPH molecules?
a. 1
b. 2
c. 3
d. 4
e. 5

A

2

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25
Q

NADPH is an important component in the means by which cells combat oxidative stress because it is needed to recycle:
a. Catalase
b. Glutathione
c. Superoxide Dismutase
d. Thioredoxin
e. Thioredoxin Reductase

A

GLUTATHIONE

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26
Q

Which of the following does not inactivate the barrier function of perilipin (by either direct or indirect means)?
a. a 7TM receptor
b. cyclic AMP
c. epinephrine
d. insulin
e. protein kinase A

A

INSULIN

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27
Q

What cofactor is required for the catabolism of fatty acids with an odd number of carbons that is not required for the catabolism of fatty acids with an even number of carbons?
a. carnitine
b. cobalamin
c. pyridoxal phosphate
d. tetrahydrofolate
e. tetrahydrobiopterin

A

COBALAMIN

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28
Q

Acetyl units needed for fatty acid synthesis are exported across the inner mitochondrial membrane as:
a. acetyl-CoA
b. acetyl-carnitine
c. acetyl-ACP
d. malonyl-CoA
e. citrate

A

CITRATE

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29
Q

Which of the following is a true statement about AMP-activated protein kinase (AMPK)?
a. AMPK activity stimulates acetyl-CoA carboxylase
b. AMPK is inhibited by epinephrine signaling
c. AMPK is inhibited by glucagon signaling
d. AMPK is inhibited by insulin signaling
e. AMPK is inhibited by low energy charge

A

AMPK IS INHIBITED BY INSULIN SIGNALING

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30
Q

After two days of fasting, the liver converts fatty acids mostly to:
a. CO2
b. citric acid cycle intermediates
c. glucose
d. ketone bodies
e. ketogenic amino acids

A

KETONE BODIES

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31
Q

The activated form of a fatty acid used in triacylglycerol synthesis is:
a. fatty acyl-ADP
b. fatty acyl carnitine
c. fatty acyl-CDP
d. fatty acyl-CoA
e. fatty acyl-UDP

A

FATTY ACYL-COA

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32
Q

An amino acid that is incorporated into the structures of both sphingolipids and some glycerophospholipids is:
a. aspartate
b. glutamine
c. glycine
d. methionine
e. serine

A

SERINE

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33
Q

Compared to LDL particles, VLDL particles have a composition that is relatively rich in:
a. apolipoproteins
b. cholesterol and cholesterol esters
c. free fatty acids
d. phospholipids
e. triacylglycerols

A

TRIACYLGLYCEROLS

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34
Q

Which of the following is a true statement about secretin?
a. Secretin is a steroid hormone
b. Secretin is produced as a zymogen
c. Secretin stimulates the gall bladder to release bile
d. Secretin stimulates the liver to upregulate amino acid catabolism
e. Secretin stimulates the pancreas to release bicarbonate

A

SECRETIN STIMULATES THE PANCREAS TO RELEASE BICARBONATE

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34
Q

The deamination of serine to produce pyruvate requires which of the following co-factors:
a. Biotin
b. NADP+ or NAD+
c. Pyridoxal Phosphate
d. Tetrahydrofolate
e. Thiamine

A

PYRIDOXAL PHOSPHATE

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35
Q

Ornithine and urea are produced from the hydrolytic cleavage of which amino acid?
a. Arginine
b. Glutamate
c. Glutamine
d. Lysine
e. Serine

A

ARGININE

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36
Q

Which of the following is not a true statement? The biological fixation of N2 as ammonia:
a. Has a large activation energy
b. Has a negative delta G prime
c. Requires a large input of energy
d. Requires O2
e. Takes place at ambient temperatures and normal atmospheric pressure

A

REQUIRES O2

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37
Q

Glutamine is synthesized from activated glutamate. How is glutamate activated?
a. By ATP-driven phosphorylation of the a-carboxyl
b. By ATP-driven phosphorylation of the y-carboxyl
c. By the formation of the ADP-glutamate
d. By the formation of CDP-glutamate
e. By the formation of UDP-glutamate

A

BY THE ATP-DRIVEN PHOSPHORYLATION OF THE Y-CARBOXYL

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38
Q

Which of the following is an “essential” amino acid?
a. Arginine
b. Aspartate
c. Glutamate
d. Glutamine
e. Tryptophan

A

ARGININE AND TRYPTOPHAN

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39
Q

The methyl group on the side chain of methionine comes from:
a. a reaction requiring biotin
b. a reaction requiring thiamine
c. N5-methyl-tetrahydrofolate
d. S-adenosylmethioine
e. the pentose phosphate pathway

A

N5-METHYL-TETRAHYDROFOLATE

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40
Q

Which of the following describes steps in the de novo synthesis of pyrimidines?
a. Carbamoylphosphate condenses with ornithine to form carbamoylaspartate
b. Formation of carbamate occurs in the mitochondria
c. The carbon in carbamate comes from aspartate
d. The formation of carboxyphosphate requires thiamine
e. The nitrogen in carbamate comes from glutamine

A

THE NITROGEN IN CARBAMATE COMES FROM GLUTAMINE

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41
Q

Which of the following statements concerning the de novo synthesis of purine and pyrimidines is false.
a. The de novo synthesis of purines and pyrimidines require 5-phosphoribosyl-1-pyrophosphate (PRPP)
b. The de novo synthesis of purines and pyrimidines assemble the base first and then attach it to the sugar
c. The first step in the de novo synthesis of purines is the formation of an N-glycosidic bond
d. The purine ring is assembled from many different components
e. The pentose phosphate pathway provides an essential component for the synthesis of both purines and pyrimidines

A

THE DE NOVO SYNTHESIS OF PURINES AND PYRIMIDINES ASSEMBLE THE BASE FIRST AND THEN ATTACH IT TO THE SUGAR

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42
Q

Which of the following is not a substrate for ribonucleotide reductase?
a. ADP
b. CDP
c. GDP
d. UDP
e. TDP

A

TDP

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43
Q

At the start of a chemical reaction (only reactants present and before any product has formed), which of the following is true?
a. Delta G = 0
b. Delta G = Delta G degree
c. Delta G = Delta G degree prime
d. Delta G has a large, negative value
e. Delta G has a large, positive value

A

DELTA G HAS A LARGE, NEGATIVE VALUE

44
Q

Which of the following is not a reason why the hydrolysis of phosphoanhydride bonds release more Gibbs free energy than does the hydrolysis of phosphoester bonds?
a. Greater electrostatic repulsion in phosphoanhydrides than phosphoesters
b. Greater energy release from resonance stabilization in the products of phosphanhydride hydrolysis compared to the products of phosphoester hydrolysis
c. Phosphoanhydrides have more bond energy than phosphoesters
d. The hydrolysis of phosphoanhydrides has a greater gain of entropy compared to the hydrolysis of phosphoesters
e. The hydration of the products of phosphoanhydride hydrolysis is greater than that from the products of phosphoester hydrolysis

A

PHOSPHOANHYDRIDES HAVE MORE BOND ENERGY THAN PHOSPHOESTERS

45
Q

What is the oxidation state of the carbonyl carbon (carbon 2) of oxaloacetate?

A

+2

46
Q

Which of the following is a true statement?
a. glucose and fructose use the same transporter to enter intestinal epithelial cells
b. both glucose and fructose are phosphorylated by hexokinase in liver cells
c. both glucose and fructose are products of starch digestion by the combined action of amylase and sucrase
d. both glucose and fructose can be used to generate ATP by the glycolytic pathway
e. glucose and fructose are symported with Na+ into intestinal epithelial cells

A

BOTH GLUCOSE AND FRUCTOSE CAN BE USED TO GENERATE ATP BY THE GLYCOLYTIC PATHWAY

47
Q

Which of the following is not true of the activity of hexokinase?
a. Creates a high energy bond that can be used to phosphorylate ADP
b. Is inhibited by its own product
c. Prevents fructose-6-phosphate from adopting a pyranose confirmation
d. raises the concentration of glucose-6-phosphate in the cell relative to glucose
e. traps glucose-6-phosphate within the cell

A

CREATES A HIGH ENERGY BOND THAT CAN BE USED TO PHOSPHORYLATE ADP

48
Q

Which of the following is true about what happens to the compound pictured below during glycolysis?
a. dehydrated to form an enolphosphate
b. hydrolyzed with water to form glycerate and free phosphate
c. oxidized by NAD+ to form the diacid
d. phosphorylated by ATP to form the bisphosphate
e. used to phosphorylate ADP to make ATP

A

DEHYDRATED TO FORM ENOLPHOSPHATE

49
Q

The structure shown is generated from pyruvate by:
a. hydrolysis of an acylphosphate at C1
b. hydrolysis of a phosphoester at C2
c. hydration of a double bond between C2 and C3 to form an alcohol
d. oxidation of a carbonyl at C3 to a carboxylic acid
e. reduction of a carbonyl at C2 to an alcohol

A

REDUCTION OF A CARBONYL AT C2 TO AN ALCOHOL

50
Q

Which of the following reactions is the committed step for glycolysis?
a. dihydroxyacetone-phosphate to glyceraldehyde-3-phosphate
b. fructose-1,6-bisphosphate to glyceraldehyde-3-phosphate + dihydroxyacetone phosphate
c. fructose-6-phosphate + ATP to fructose-1,6-bisphosphate + ADP
d. glucose + ATP to glucose-6-phosphate + ADP
e. glucose-6-phosphate to fructose-6-phosphate

A

FRUCTOSE-6-PHOSPHATE + ATP TO FRUCTOSE-1,6-BISPHOSPHATE + ADP

51
Q

The structure shown is
a. a carrier for activated glucose
b. a carrier for activated hydride ions
c. a carrier for activated phosphates
d. a vitamin-derived compound used for carrying out oxidations
e. the product of the third step of glycolysis

A

A CARRIER FOR ACTIVATED GLUCOSE

52
Q

Which of the following is not a true statement?
a. Glucokinase and kexokinase are isozymes
b. Glucokinase and hexokinase have different amino acid sequences
c. Glucokinase has a higher Km for glucose than does hexokinase
d. Glucose-6-phosphate inhibits glucokinase, but not hexokinase
e. Hexokinase, but not glucokinase, can phosphorylate fructose on C6

A

GLUCOSE-6-PHOSPHATE INHIBITS GLUCOKINASE BUT NOT HEXOKINASE

53
Q

Which of the following vitamins is necessary for the function of pyruvate carboxylase?
a. biotin
b. folate
c. niacin
d. pantothenate
e. riboflavin

A

BIOTIN

54
Q

Which of the following is true regarding the regulation of phosphofructokinase (PFK)?
a. AMP is a negative regulator
b. ATP is a positive regulator
c. Citrate is a negative regulator
d. Fructose-1,6-bisphosphate is a positive regulator
e. Low pH is a positive regulator

A

CITRATE IS A NEGATIVE REGULATOR

55
Q

Which of the following is not a product of the pyruvate dehydrogenase complex?
a. acetyl-CoA
b. ADP
c. CO2
d. H+
e. NADH

A

ADP

56
Q

Which of the following is not true about the regulation of the pyruvate dehydrogenase complex?
a. Acetyl-CoA is a positive regulator
b. ADP is a negative regulator
c. Ca2+ is a positive regulator
d. NADH is a positive regulator
e. Pyruvate is a negative regulator

A

CA2+ IS A POSITIVE REGULATOR

57
Q

An example of an anapleurotic reaction is:
a. the carboxylation of pyruvate to generate oxaloacetate
b. the condensation of oxaloacetate and acetyl-CoA to generate citrate and coenzyme A
c. the coupling of ADP phosphorylation to succinyl-CoA hydrolysis
d. the oxidation of isocitrate by NAD+ to create oxalosuccinate and NADH
e. the oxidative decarboxylation of a-ketoglutarate to generate succinyl-CoA

A

THE CARBOXYLATION OF PYRUVATE TO GENERATE OXALOACETATE

58
Q

Citrate synthase hydrolyzes citryl-CoA, but not acetyl-CoA because
a. acetyl-CoA is an allosteric regulator of citrate synthase
b. acetyl-CoA is difficult to hydrolyze
c. acetyl-CoA is not a substrate of citrate synthase
d. citrate synthase uses an induced fit mechanism
e. unlike citryl-CoA, acetyl-CoA lacks a B-hydroxyl that participates in the hydrolytic mechanism

A

CITRATE SYNTHASE USES AN INDUCED FIT MECHANISM

59
Q

Dietary lipids are emulsified in the gut primarily through the action of:
a. derivatives of cholesterol
b. fatty acids that act as detergents
c. intestinal albumin
d. micelle-generating proteins secreted by the pancreas
e. salivary enzymes

A

DERIVATIVES OF CHOLESTEROL

60
Q

Lipases are enzymes that:
a. attach fatty acids to lipid-anchored membrane proteins
b hydrolyze the ester bonds between a fatty acyl group and glycerol
c. import fatty acids into the mitochondria
d. reassemble lipids from fatty acids and glycerol
e. transport lipids across the plasma membrane

A

HYDROLYZE THE ESTER BONDS BETWEEN A FATTY ACYL GROUP AND GLYCEROL

61
Q

Pepsinogen is activated by:
a. cholecystokinin
b. dephosphorylation
c. phosphorylation
d. secretin
e. self-clevage

A

SELF-CLEAVAGE

62
Q

How many protons does complex 1 pumped in the mitochondrial membrane space when it transfers electrons from NADH to coenzyme Q?
a. 0
b. 1
c. 2
d. 3
e. 4

A

4

63
Q

Complex 2 transfers electrons from succinate to coenzyme Q using an intermediate derived from what vitamin?
a. folate
b. niacin
c. pantothenate
d. riboflavin
e. thiamine

A

RIBOFLAVIN

64
Q

Which of the following is not considered to be a ROS?
a. Hydrogen peroxide (HOOH)
b. Hydroxide (OH-)
c. Hydroxyl radical (OH)
d. Superoxide ion (O2-)
e. Diatomic oxygen (O2)

A

HYDROXIDE

65
Q

How many different coenzyme Q molecules are involved in one complete round of the Q cycle?

A

3

66
Q

Each 360 degree rotation of the gamma subunit of the F1Fo ATPase generates how many ATPs?

A

3

67
Q

In muscle, the electrons captured in NADH from glycolysis enter the mitochondria by:
a. a pathway involving citrate
b. a pathway involving glycerol-3-phosphate
c. a pathway involving lactate
d. an antiporter that exchanges NADH for NAD+
e. the Cori cycle

A

A PATHWAY INVOLVING GLYCEROL-3-PHOSPHATE

68
Q

Cyanide is a complex IV (cytochrome c oxidase) inhibitor. Which of the following would be expected to occur in a, for the moment, still-living victim of cyanide poisoning?
a. Flux through the TCA cycle would increase
b. Mitochondrial NADH levels would drop precipitously
c. O2 consumption would decline
d. Pyruvate decarboxylase would be stimulated
e. The FAD/FADH2 ratio in the mitochondria would be abnormally high

A

O2 CONSUMPTION WOULD DECLINE

69
Q

What co-factor is used to remove a1 to a4 linked glucosyl residues from the end of glycogen molecules?
a. ATP
b. biotin
c. co-enzyme A
d. phosphate
e. water

A

PHOSPHATE

70
Q

Glucosyl residues are removed from a1 to 6 branch sites as:
a. CDP-glucose
b. glucose
c. glucose-1-phosphate
d. glucose-6-phosphate
e. UDP-glucose

A

GLUCOSE

71
Q

Glycogen phosphorylase in the liver:
a. is converted to the T state by high AMP levels
b. is inactivated by Ca2+
c. is stimulated by high glucose levels in the blood
d. tends to be in the T state
e. tends to be in the P-phosphorylase a form

A

TENDS TO BE IN THE P-PHOSPHORYLASE A FORM

72
Q

One of the substrates used by glycogen synthase to add glucosyl units to an existing glycogen molecule is:
a. ADP-glucose
b. CDP-glucose
c. glucose-1-phosphate
d. glucose-6-phosphate
e. UDP-glucose

A

UDP-GLUCOSE

73
Q

Branching enzyme:
a. adds a single activated glucosyl residue to an existing glycogen molecule by an a1 to 6 linkage
b. creates branches by joining two existing glycogen molecules to each other
c. increases the frequency by which glycogen synthase occasionally misincorporates glucosyl residues at a1 to 6 sites
d. isomerizes an internal glucosyl residue in glycogen so that the C-4 carbon becomes a C-6 carbon
e. moves a string of glucosyl residues attached to glycogen via an a1 to 4 linkage to an a1 to 6 linkage

A

MOVES A STRING OF GLUCOSYL RESIDUES ATTACHED TO GLYCOGEN VIA AN A1 TO 4 LINKAGE TO AN A1 TO 6 LINKAGE

74
Q

In the regulatory pathway shown below, when glycogen synthesis is required:
a. both glucagon and epinephrine levels will be high
b. either the level of glucagon or epinephrine will be high
c. phosphorylase kinase will be active
d. phosphorylase will be dephosphorylated
e. protein kinase A will be active

A

PHOSPHORYLASE WILL BE DEPHOSPHORYLATED

75
Q

In the first step of the pentose phosphate pathway NADP+ is used to convert glucose-6-phosphate to (compound pictured):
a. an acetal
b. an aldehyde
c. a carboxylate
d. a ketone
e. a lactone

A

A LACTONE

76
Q

In the oxidative phase of the pentose phosphate pathway, how many NADPH’s can be generated from a single glucose-6-phosphate molecule?

A

2

77
Q

Fatty acids are transported from the cytoplasm to the mitochondria through the action of:
a. acyl carrier protein (ACP)
b. carnitine
c. creatine
d. fatty acid binding protein (FABP)
e. fatty acid transport protein (FATP)

A

CARNITINE

78
Q

Fatty acid degradation generates the trans delta 2 enoyl-CoA intermediate shown. What type of enzyme acts in the next step of this process?
a. A hydratase that adds water to the double bond
b. An isomerase that converts it to cis delta 2 enoyl-CoA
c. A mutase that moves the CoA moiety to the C3 position
d. A saturase that uses FADH2 to convert the double bond to a single bond
e. A thiolase that attaches to CoASH to C-3 and cleaves the double bond releasing acetyl-CoA

A

A HYDRATASE THAT ADDS WATER TO THE DOUBLE BOND

79
Q

During starvation, the body relies on ketone bodies to feed the brain because
a. fatty acids and triacylglycerols can’t cross the blood-brain barrier
b. glycogen catabolism is inhibited by fasting
c. ketone bodies refocus the brain to concentrate on strategies for finding more food
d. ketone bodies are what the brain usually used for its energy needs whether or not starvation is occuring
e. the glucose made from fatty acids in the liver is diverted to the muscles which need it for hunting and gathering

A

FATTY ACIDS AND TRIACYLGLYCEROLS CANT CROSS THE BLOOD-BRAIN BARRIER

80
Q

To be used for fatty acid synthesis, acetyl-CoA has to move from the mitochondria to the cytoplasm. This can be accomplished by:
a. an antiporter that simultaneously transports coenzyme A into the mitochondria
b. an antiporter that simultaneously transports H+ into the mitochondria
c. first carboxylating acetyl-CoA to form pyruvate
d. first condensing acetyl-CoA with oxaloacetate to make citrate
e. first forming it into ketone bodies

A

FIRST CONDENSING ACETYL-COA WITH OXALOACETATE TO MAKE CITRATE

81
Q

When palmitate (a saturated 16 carbon fatty acid) is synthesized, fatty acid synthase repeatedly carries out which of the following series of events:
a. a condensation, a reduction, a carboxylation, and a reduction
b. a condensation, a reduction, a decarboxylation, and a reduction
c. a condensation, a reduction, a dehydration, and a reduction
d. a condensation, a reduction, an isomerization, and a reduction
e. a condensation, a reduction, an oxidation, and a reduction

A

A CONDENSATION, A REDUCTION, A DEHYDRATION, AND A REDUCTION

82
Q

The enzyme that converts oleic acid to linoleic acid is:
a. a desaturase
b. a hydrolase
c. an isomerase
d. a reductase
e. a transferase

A

A DESATURASE

83
Q

What modification activates serine so that it can be used to make phosphatidylserine:
a. adenylation
b. carboxylation
c. cytidylayion
d. uridylation
e. phosphorylation

A

CYTIDYLATION

84
Q

According to the regulatory scheme below, one effect of excess CDP-diacylglycerol will be to:
a. decrease diacylglycerol kinase activity
b. increase cardiolipin synthesis
c. increase diacylglycerol kinase activity
d. increase triacylglycerol synthesis
e. inhibit phosphatidic acid phosphate activity

A

INCREASE TRIACYLGLYCEROL SYNTHESIS

85
Q

The “statin” class of pharmaceuticals that are used to lower blood cholesterol levels inhibit:
a. the ability of HDL to take up cholesterol into the blood
b. the condensation of two isopentenyl pyrophosphates to form geranyl pyrophosphate
c. the conversion of hydroxyl-methyl glutaryl-CoA to form mevalonate
d. the cyclization of squalene to form lanosterol
e. the loading of cholesterol into VLDLs

A

THE CONVERSION OF HYDROXYL-METHYL GLUTARYL-COA TO FORM MEVALONATE

86
Q

Which of the following is a true statement about transport proteins that ferry lipids through the bloodstream?
a. chylomicrons use the hepatic portal system to bring lipids directly to the liver
b. HDLs are produced by the liver to ferry cholesterol to tissues that need them
c. LDLs are lipoproteins that are depleted of triacylglycerols
d. Serum albumin transports mainly triacylglycerols from liver to adipose cells
e. VLDLs are formed from LDLs as they travel through the circulatory system

A

LDLS ARE LIPOPROTEINS THAT ARE DEPLETED OF TRIACYLGLYCEROLS

87
Q

The immediate precursor for urea in the urea cycle is:
a. arginine
b. asparagine
c. aspartate
d. bicarbonate and two ammonia molecules
e. glutamine

A

ARGININE

88
Q

In a reaction requiring pyridoxal phosphate, a dehydratase removes ammonia from serine to generate:
a. a-ketoglutarate
b. citrate
c. glyceraldehyde
d. oxaloacetate
e. pyruvate

A

PYRUVATE

89
Q

Which of the following carriers is/are used to transport, through the bloodstream to the liver, nitrogen destined for the urea cycle?
a. alanine and glutamine
b. ammonia
c. any and all amino acids
d. carbamic acid
e. uric acid

A

ALANINE AND GLUTAMINE

90
Q

The catabolic opening of an aromatic ring, such as the one pictured, generally requires the action of a:
a. dehydratase
b. dehydrogenase
c. dioxygenase
d. mutase
e. transferase

A

DIOXYGENASE

91
Q

Free ammonia can be incorporated into amino acids by three different pathways. Which of the following is a true statement? Ammonia:
a. can be incorporated into a-ketoglutarate to make glutamate by a reaction requiring ATP
b. can be incorporated into glutamate to make glutamine by a reaction requiring ATP
c. can be incorporated into carboxyphosphate to make carbamic acid by a reaction requiring NADPH or NADH
d. is first phosphorylated using ATP to form phosphoamide before being added to an a-keto acid to make an a-amino acid
e. is so toxic that it is rapidly excreted an none of the incorporation pathways actually exist in human systems

A

CAN BE INCORPORATED INTO GLUTAMATE TO MAKE GLUTAMINE BY A REACTION REQUIRING ATP

92
Q

When an aminotransferase acts on glutamate and oxaloacetate, it produces a-ketoglutarate and:
a. alanine
b. ammonia
c. aspartate
d. glutamine
e. pyruvate

A

ASPARTATE

93
Q

In the S-adenosylmethionine (SAM) cycle, which vitamin is required to produce a co-factor needed to put the methyl group on homocysteine to form methionine?
a. biotin
b. folate
c. niacin
d. panthothenate
e. thiamine

A

FOLATE

94
Q

The nucleoside bases are attached to the ribose at which carbon?
a. the 1’ carbon
b. the 2’ carbon
c. the 3’ carbon
d. the 4’ carbon
e. the 5’ carbon

A

THE 1’ CARBON

95
Q

In de novo nucleotide biosynthesis:
a. both pyrimidine and purine rings are assembled first and then added to PRPP
b. both pyrimidine and purine rings are assembled piece-by-piece on PRPP
c. both pyrimidines and purines are partially assembled but the aromatic rings aren’t closed until after the partially assembled pieces are added to PRPP
d. the pyrimidine ring is assembled first and then added to PRPP, but the purine is assembled piece-by-piece on PRPP
e. the pyrimidine ring is assembled piece-by-piece on PRPP, but the purine is assembled first and then added to PRPP

A

THE PYRIMIDINE RING IS ASSEMBLED FIRST AND THEN ADDED TO PRPP, BUT THE PURIN EIS ASSEMBLED PIECE BY PIECE ON PRPP

96
Q

Which of the following enzymes does not exist?
a. dAMP kinase
b. cCMP kinase
c. dGMP kinase
d. dUMP kinase
e. TMP kinase

A

dUMP KINASE

97
Q

Uric acid is an end product of purine catabolism and can serve as an antioxidant. When uric acids levels in the bloodstream get too high:
a. a disease syndrome (Lesch-Nyhan), in which victims have a bizarre tendency to self-mutilate, results
b. the immune system is damaged resulting in severe combined immunodeficiency (SCID)
c. the liver recycles it back into purines using the salvage pathway
d. the liver uses mono- and dioxygenases to convert it to urea for elimination in the urine
e. uric acid crystals can precipitate out in the fluid and lining of the joints, causing gout

A

URIC ACID CRYSTALS CAN PRECIPITATE OUT IN THE FLUID AND LINING OF THE JOINTS, CAUSING GOUT

98
Q

Which of the following enzymes is expected to be regulated by energy charge?
a. aconitase
b. fumarase
c. isocitrate dehydrogenase
d. malate dehydrogenase
e. succinate dehydrogenase

A

ISOCITRATE DEHYDROGENASE

99
Q

For the model reaction, A (double arrow) B, under what conditions does equilibrium occur?

A

when delta g = 0

100
Q

To what class of phosphocompounds does the compound pictured belong?
a. acylphosphate
b. phosphoanhydride
c. phosphoenol
d. phosphoester
e. phosphoguanidine

A

PHOSPHOGUANIDINE

101
Q

To enter glycolysis, which of the following sugars needs to be processed by a reaction that requires UDP- glucose?
a. a-limit dextran
b. fructose
c. galactose
d. maltose
e. sucrose

A

GALACTOSE

102
Q

The structure shown is:
a. Biotin
b. Coenzyme A
c. FAD
d. Lipoamide
e. Thiamine Pyrophosphate

A

LIPOAMIDE

103
Q

In the normal operation of the CAC, what happens next to the compound shown?
a. it is dehydrated
b. it is isomerized
c. it is oxidized
d. it is phosphorylated
e. it is reduced

A

IT IS OXIDIZED

104
Q

Which CAC enzyme is a transmembrane protein embedded in the inner mitochondrial membrane?
a. a-ketoglutarate dehydrogenase
b. citrate synthase
c. isocitrate dehydrogenase
d. malate dehydrogenase
e. succinate dehydrogenase

A

SUCCINATE DEHYDROGENASE

105
Q

Which of the following reactions is an anapleurotic reaction?
a. citrate to isocitrate
b. isocitrate + NAD+ to a-ketoglutarate + NADH + CO2
c. pyruvate + ATP + CO2 to oxaloacetate + ADP + Pi
d. succinate + FAD to fumarate + FADH2
e. succinyl-CoA + ADP + Pi to succinate + ATP + coenzyme A

A

PYRUVATE + ATP + CO2 TO OXALOACETATE + ADP + PI

106
Q

The reaction pictured is catalyzed by:
a. a dehydrogenase
b. an epimerase
c. an isomerase
d. a transaldolase
e. a transketolase

A

A TRANSALDOLASE

107
Q

What pathway does not utilize the interconversion of malate and oxaloacetate?
a. citric acid cycle
b. fatty acid synthesis
c. gluconeogenesis
d. pentose phosphate pathway
e. urea cycle

A

PENTOSE PHOSPHATE PATHWAY

MADI B (6 decks)

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