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190 Cards in this Set

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The DIRECT energy source for oxidative phosphorylation is

* Glucose
* Acetyl CoA
* NADH
* Oxygen
* Hydrogen ion gradient
* Hydrogen ion gradient
Which enzyme hydrolyzes high energy phosphate (~P)?

* SuccinylCoA synthase
* Pyruvate carboxylase
* Malate dehydrogenase
* Pyruvate dehydrogenase
* Pyruvate kinase
* Pyruvate carboxylase
What is the primary compound leaving mitochondria in the traditional view of energy transport in cells?

* Phosphocreatine
* Creatine
* ATP
* ADP
* CO2
* ATP
The first carbon to be removed from glucose and be expelled in the form of CO2 occurs

* at the reaction catalyzed by pyruvate carboxylase
* at the reaction catalyzed by phosphofructokinase
* at the reaction catalyzed by pyruvate dehydrogenase
* in the cytoplasm
* in the intramembranous space of the mitochondrion
* at the reaction catalyzed by pyruvate dehydrogenase
Which of the following statements about pyruvate dehydrogenase is FALSE?

* PDH is located in mitochondria
* PDH is the 4th energy harvest from glucose
* PDH activity is stimulated by acetylCoA
* The PDH reaction produces 2 carbon dioxides per glucose
* The PDH reaction is irreversible
* PDH activity is stimulated by acetylCoA
The enzyme responsible for the interconversion of glucose-1-phosphate and glucose-6-phosphate is

* transferase
* phosphorylase
* glucosidase
* phosphoglucomutase
* glucose-6-phosphatase
* phosphoglucomutase
The key regulatory enzyme for committing glucose carbons to glycolysis is

* Hexokinase
* Phosphofructokinase
* Triose phosphate isomerase
* Pyruvate dehydrogenase
* Aldolase
* Phosphofructokinase
The first carbon to be removed from glucose and be expelled in the form of CO2 occurs

* at the reaction catalyzed by pyruvate carboxylase
* at the reaction catalyzed by phosphofructokinase
* at the reaction catalyzed by pyruvate dehydrogenase
* in the cytoplasm
* in the intramembranous space of the mitochondrion
* at the reaction catalyzed by pyruvate dehydrogenase
Which enzyme catalyzes a reaction which yields usable energy in ANAEROBIC conditions?

* Pyruvate kinase
* Phosphofructokinase
* Glyceraldehyde-3-phosphate dehydrogenase
* Pyruvate dehydrogenase
* Hexokinase
Pyruvate kinase
Which of the following is NOT a regulatory enzyme of glycolysis?

* Pyruvate kinase
* Hexokinase
* Phosphoglycerate kinase
* Phosphofructokinase
* All of the above are regulatory enzymes of glycolysis.
Phosphoglycerate kinase
This is the first product of glycolysis whose carbons are “committed” to glycolysis:

* Glucose-1-phosphate
* Glucose-6-phosphate
* Fructose-6-phosphate
* Fructose-1,6-bisphosphate
* Phosphoenolpyruvate
* Fructose-1,6-bisphosphate
Which enzyme hydrolyzes high energy phosphate (~P)?

* SuccinylCoA synthase
* Pyruvate carboxylase
* Malate dehydrogenase
* Pyruvate dehydrogenase
* Pyruvate kinase
* Pyruvate carboxylase
The reactions of the TCA cycle take place in the

* cytoplasm
* mitochondrial matrix
* outer mitochondrial membrane
* nucleus
* cytoplasm and mitochondrial matrix
* mitochondrial matrix
You are accidentally injected with a newly synthesized enzyme which enters your cells and converts α-ketoglutarate to oxaloacetate without using NAD+ or FAD. Which of the following statements is TRUE?

* Carbon dioxide is probably produced by the reaction
* The Go' of the reaction is probably large and negative
* There will be a substantial loss of energy harvested compared to the normal TCA cycle
* The new set of reactions will still be a cycle
* All of the above are true
* All of the above are true
One of the following compounds does NOT slow down the rate of the TCA cycle. Which one is the EXCEPTION?
* All of the above slow the TCA cycle
The first energy harvest in the TCA cycle is catalyzed by
* isocitrate dehydrogenase
Pyruvate carboxylase

* converts pyruvate to amino acid precursor molecules
* converts succinyl CoA to precursors of porphyrin rings
* combines carbon dioxide and pyruvate to produce oxaloacetate
* produces acetyl CoA and ATP
* produces pyruvate while transferring a carboxyl group to glutamate
* combines carbon dioxide and pyruvate to produce oxaloacetate
The key regulatory enzyme for entry of carbon into the TCA cycle is

* Citrate synthase
* Isocitrate dehydrogenase
* Malate dehydrogenase
* Aconitase
* Pyruvate dehydrogenase
* Citrate synthase
Which of the following is inhibited by high ATP or NADH, stimulated by ADP or NAD+, and produces carbon dioxide?

* Isocitrate dehydrogenase
* Succinate dehydrogenase
* Malate dehydrogenase
* All of the above
* None of the above
Isocitrate dehydrogenase
The DIRECT energy source for oxidative phosphorylation is

* Glucose
* Acetyl CoA
* NADH
* Oxygen
* Hydrogen ion gradient
* Hydrogen ion gradient
Electron transport provides the cell with enough energy from one molecule of glucose to phosphorylate how many molecules of ADP?

* 24
* 26
* 28
* 32
* 34
* 34
When electrons are passed from Compound Y to Compound X

* Compound Y is oxidized during the reaction
* Compound X is oxidized during the reaction
* Compound Y usually keeps any hydrogen ions associated with the electrons
* Compound Y gains energy
* All of the above
* Compound Y is oxidized during the reaction
NADH-Q Reductase is the first component of the electron transport chain and

* is composed of flavin mononucleotide (FMN) and ubiquinone
* passes electrons directly to cytochrome reductase
* transports two hydrogen ions across the inner mitochondrial membrane
* accepts electrons from NADPH
* accepts electrons from ubiquinone
* transports two hydrogen ions across the inner mitochondrial membrane
ATP synthase

* consumes ATP in the process of producing translocase
* synthesizes ATP from phosphocreatine
* uses the energy of a hydrogen ion gradient to phosphorylate ADP
* is a tube through the outer mitochondrial membrane which allows ATP to exit
* All of the above are true
* uses the energy of a hydrogen ion gradient to phosphorylate ADP
2,4-dinitrophenol (2,4-DNP)

* is an uncoupler
* does NOT prevent electron transport
* dissipates the hydrogen ion gradient in mitochondria
* has an effect similar to that of thermogenin, a naturally occurring compound
* All of the above are true
* All of the above are true
Which of the following is reduced by FADH2?

* NADH-Q reductase
* Coenzyme Q (Ubiquinone)
* Cytochrome reductase
* Cytochrome c
* Cytochrome oxidase
* Coenzyme Q (Ubiquinone)
Which of the following would increase heat and CO2 production while also increasing glucose catabolism?

* Cyanide
* Azide
* Antimycin A
* 2,4-dinitrophenol
* Actinomycin
* 2,4-dinitrophenol
Glycogen

* granules are complexes of glycogen and the enzymes involved in synthesis and catabolism
* is highest in concentration in liver cells
* is stored in muscle cells
* metabolism is regulated by hormones
* All of the above are correct
* All of the above are correct
The enzyme which accomplishes the majority of glycogen catabolism is

* glycogen synthase
* glycogen phosphorylase
* alpha-1,6-glucosidase
* glucosyl-4,4-transferase
* glucose-6-phosphatase
* glycogen phosphorylase
During the catabolism of a glycogen molecule both glucose-1-phosphate and glucose are released. Which enzyme releases glucose directly during glycogen catabolism?

* Glycogen synthase
* Glycogen phosphorylase
* alpha -1,6-glucosidase
* Glycogen transferase
* Glucose-6-phosphatase
* alpha -1,6-glucosidase
Which of the following statements about glycogen synthase is INCORRECT?

* It can act on glycogen chains only if they are at least 4 glucose units long
* It uses UDP-glucose as a glucose donor
* The product of the reaction is glycogenn+1
* It can produce both α-1,4 and α-1,6 linkages
* It is an enzyme
* It can produce both α-1,4 and α-1,6 linkages
Which of the following would tend to slow the rate of glycogen synthesis?

* Inhibition of phosphodiesterase
* Inhibition of UDP-glucose phosphorylase
* Inhibition of glycogen synthase
* Destruction of cellular glycoproteins
* All of the above would tend to slow glycogen synthesis
* All of the above would tend to slow glycogen synthesis
Which of the following enzymes uses UDP-glucose as a substrate?

* UDP-glucose pyrophosphorylase
* Glycogen phosphorylase
* Glycogen synthase
* Phosphoglucomutase
* ATP synthase
* Glycogen synthase
Which enzyme is responsible for cleaving the branch points in glycogen molecules?

* Glycogen phosphorylase a
* Glycogen phosphorylase b
* Glycogen branching enzyme
* Glycogen synthase
* Amylo-(1,6)-glucosidase
* Amylo-(1,6)-glucosidase
Which of the following is a purpose of the pentose phosphate shunt?

* Produce NADPH for energy transport
* Produce NADH for biosynthesis
* Produce NADPH for biosynthesis
* Produce NADH for energy transport
* All of the above are accomplished by the shunt
* Produce NADPH for biosynthesis
The rate-limiting reaction in the pentose phosphate pathway

* is catalyzed by glucose-6-phosphate dehydrogenase
* is accelerated by the presence of NADP+
* produces 6-phosphogluconolactone
* produces NADPH
* All of the above are correct
* All of the above are correct
In which of the following tissues would you expect to see the highest pentose phosphate shunt activity?

* Liver
* Brain
* Heart
* Colon
* Spleen
* Liver
Transketolase can use two molecules of ____________ as substrate.

* Ribose-5-phosphate
* 6-phosphogluconolactone
* 6-phosphogluconate
* Glucose-6-phosphate
* Dihydroxyacetone phosphate
* Ribose-5-phosphate
The product of the rate-limiting reaction in the pentose phosphate shunt is

* Ribose-5-phosphate
* 6-phosphogluconolactone
* 6-phosphogluconate
* Glucose-6-phosphate
* Dihydroxyacetone phosphate
* 6-phosphogluconolactone
Carbon can be returned to glycolysis from the pentose phosphate shunt in the form of

* glucose-6-phosphate and fructose-6- phosphate
* fructose-6-phosphate and glyceraldehyde-3-phosphate
* glucose-6-phosphate and dihydroxyacetone phosphate
* fructose-6-phosphate only
* dihydroxyacetone phosphate only
* fructose-6-phosphate and glyceraldehyde-3-phosphate
In a situation where the rate of DNA synthesis is high, the use of which of the following enzymes would probably DECREASE?

* Transaldolase
* Phosphopentose isomerase
* Glucose-6-phosphate dehydrogenase
* Lactonase
* Hexokinase
* Transaldolase
The reason for having the pentose phosphate shunt is to

* provide the cell with an electron donor for biosynthesis
* provide the cell with precursor sugars for RNA and DNA synthesis
* increase the energy yield from each molecule of glucose catabolized to carbon dioxide and water
* All of the above
* A and B, but not C
* A and B, but not C
How many NADPH's are produced per glucose moiety run through the pentose phosphate shunt?

* 1
* 2
* 3
* 4
* 6
* 2
In a situation where a cell is preparing to undergo cell division, the primary end product(s) of the pentose phosphate shunt would be

* Ribulose-5-phosphate
* Ribose-5-phosphate
* Fructose-6-phosphate
* Glyceraldehyde-3-phosphate
* C and D
* Ribose-5-phosphate
The primary regulatory enzyme in the pentose phosphate shunt is

* Hexokinase
* Glucose-6-phosphate dehydrogenase
* 6-phosphogluconate dehydrogenase
* Transketolase
* Transaldolase
* Glucose-6-phosphate dehydrogenase
Which of the following would be expected when there is a large demand for ribose-5-phosphate but NOT for NADPH?

* Movement of carbons through transketolase is greater than that through 6-phosphogluconate dehydrogenase
* Movement of carbons through glucose-6-phosphate dehydrogenase is greater than that through transaldolase
* Movement of carbons through transketolase is greater than that through transaldolase
* Movement of carbons is about the same through transketolase, transaldolase, 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase
* Movement of carbons would be decreased through phosphofructokinase
* Movement of carbons through transketolase is greater than that through 6-phosphogluconate dehydrogenase
The primary control enzyme for the pentose phosphate shunt is

* Glucose-6-phosphate dehydrogenase
* Lactonase
* Phosphoglucoisomerase
* 6-phosphogluconate dehydrogenase
* Transaldolase
* Glucose-6-phosphate dehydrogenase
Inhibiting transketolase

* will not affect the pentose phosphate shunt significantly
* will not affect the shunt as much just prior to cell division compared to other times
* will prevent production of NADPH at all times
* will increase NADPH production
* All of the above are correct
* will not affect the shunt as much just prior to cell division compared to other times
Which of the following is an enzyme which catalyzes a reaction which reduces NADP+

* Thioredoxin reductase
* Lactonase
* Phosphoglucoisomerase
* 6-phosphogluconate dehydrogenase
* Transaldolase
* 6-phosphogluconate dehydrogenase
In a situation where the primary demands of the cell are for fatty acid synthesis, the primary end product(s) of the pentose phosphate shunt will be

* NADPH
* NADPH and ribose-5-phosphate
* Ribose-5-phosphate
* Ribose-5-phosphate and ATP
* NADPH and ATP
* NADPH
Which of the following enzymes produces NADPH?

* 6-phosphogluconate dehydrogenase
* Glucose-6-phosphate dehydrogenase
* Lactonase
* All of the above
* A and B, but not C
* A and B, but not C
Which of the following are functions of the hexose monophosphate shunt?

* Glucuronate synthesis for glycosaminoglycan production
* ATP production and NADH production
* Ribose-5-phosphate and NADPH production
* Ribose-5-phosphate and ATP production
* Glucuronate and NADPH production
* Ribose-5-phosphate and NADPH production
In the absence of transketolase and transaldolase, the final products of the hexose monophosphate shunt would be

* 1 NADH and 1 Ribose-5-phosphate
* 2 NADH and 1 Ribose-5-phosphate
* 1 NADPH and 1 Ribose-5-phosphate
* 2 NADPH and 1 Ribose-5-phosphate
* 1 NADPH and 2 Ribose-5-phosphate
* 2 NADPH and 1 Ribose-5-phosphate
Which of the following is NOT a precursor for gluconeogenesis?

* Lactate
* Acetyl CoA
* Glycine
* Glycerol
* Glutamate
* Acetyl CoA
Which of the following tissues has the greatest capacity for gluconeogenesis?

* Liver
* Brain
* Heart
* Adipose
* Pancreas
* Liver
Which of the following statements about gluconeogenesis is correct?

* Biotin holds activated CO2 for pyruvate carboxylase
* The ΔGo' for the net reaction is negative
* The net reaction requires 6 ATP equivalents for the synthesis of one glucose molecule
* Most of gluconeogenesis occurs in the cytoplasm
* All of the above are correct
* All of the above are correct
Which of the following compounds stimulates gluconeogenesis?

* Citrate
* Fructose-2,6-bisphosphate
* AMP
* Fructose-6-phosphate
* All of the above stimulate gluconeogenesis
* Citrate
Much of gluconeogenesis is simply the reverse of glycolysis. What key step is regulated to control the net rate of glycolysis and gluconeogenesis?

* Interconversion of PEP and 2-phosphoglycerate
* Interconversion of glucose and glucose-6-phosphate
* Interconversion of pyruvate and oxaloacetate
* Interconversion of glyceraldehyde-3-phosphate and DHAP
* Interconversion of fructose-6-phosphate and fructose-1,6-bisphosphate
* Interconversion of fructose-6-phosphate and fructose-1,6-bisphosphate
Much of gluconeogenesis takes place in the cytosol, yet many of the precursor carbon fragments are in the mitochondria. How do they get into the cytosol?

* By transport in the form of axaloacetate
* By diffusion of acetyl CoA
* By transport in the form of pyruvate
* By transport in the form of malate
* By passive diffusion
* By transport in the form of malate
Which of the following is inhibited by AMP and fructose-2,6-bisphosphate, and is stimulated by citrate?

* Phosphofructokinase
* PEP carboxykinase
* Fructose-1,6-bisphosphatase
* Pyruvate carboxylase
* Pyruvate kinase
* Fructose-1,6-bisphosphatase
Each of the following hormones stimulates fatty acid catabolism in adipocytes EXCEPT one. Which is the EXCEPTION?

* Epinephrine
* Glucagon
* ACTH
* Insulin
* Norepinephrine
Insulin
A shortage of carnitine in the body would

* decrease the rate of β-oxidation
* enhance the response of tissues to starvation
* decrease cAMP levels in adipose cells
* increase the flow of acyl groups through acyl-CoA dehydrogenase
* increase ketone bodies in the blood
* decrease the rate of β-oxidation
In normal conditions, which of the following tissues would benefit LEAST from increased blood levels of acetoacetate?

* Heart
* Liver
* Brain
* Kidney
* All of the above would benefit equally
* Brain
Which of the following tissues can normally use fatty acids for energy metabolism?

* Cardiac muscle
* Skeletal muscle
* Liver
* Adipose tissue
* All of the above
* All of the above
For each cycle of β-oxidation,

* 2 FADH2, 2 NADH and 1 acetyl CoA molecules are produced
* 1 FADH2, 1 NADH and 1 acetyl CoA molecules are produced
* 1 FADH2, 1 NADH and 2 acetyl CoA molecules are produced
* 2 FADH2, 1 NADH and 1 acetyl CoA molecules are produced
* 1 FADH2, 2 NADH and 1 acetyl CoA molecules are produced
* 1 FADH2, 1 NADH and 1 acetyl CoA molecules are produced
Which of the following enzymes is NOT necessary to metabolize a saturated fatty acid, but is necessary to metabolize an unsaturated fatty acid which has one double bond between carbons 3 and 4?

* Lipase
* Propionyl transferase
* Isomerase
* Epimerase
* Acyl-CoA dehydrogenase
* Epimerase
Epimerase is a necessary enzyme for unsaturated FA metabolism

The key regulatory enzyme for fatty acid synthesis is

* Acetyl CoA carboxylase
* Acetyl transacylase
* Acyl-carnitine transferase
* Citrate lyase
* Enoyl-ACP reductase
* Acetyl CoA carboxylase
The enzyme which commits acetyl CoA for use in fatty acid synthesis is

* acetyl transacylase
* acetyl CoA carboxylase
* acyl-malonyl-ACP condensing enzyme
* malonyl transacylase
* enoyl-ACP reductase
* acetyl CoA carboxylase
The final product produced by fatty acid synthase is

* Butyrl-ACP
* Oleate
* Crotenate
* Palmitate
* Arachidonate
* Palmitate
Which of the following is a purely ketogenic amino acid?

* Tyrosine
* Aspartate
* Glutamate
* Phenylalanine
* Lysine
* Lysine
During fatty acid synthesis two carbons are added at a time in the form of

* Acetyl CoA
* Malonyl ACP
* Acetyl ACP
* Acetoacetyl ACP
* Malonyl CoA
* Malonyl ACP
Which of the following alterations would tend to increase net fatty acid synthesis?

* Increased citrate levels
* Decreased levels of palmitoyl COA
* Decreased glucagon levels
* Increased insulin levels
* All of the above
* All of the above
What is the primary regulatory enzyme for fatty acid synthesis?

* Malonyl transacylase
* Acetyl CoA carboxylase
* Acyl-malonyl-ACP condensing enzyme
* Acetyl transacylase
* Enoyl-ACP reductase
* Acetyl CoA carboxylase
Which of the following statements would be INCORRECT if a cell could only produce even length unsaturated fatty acids?

* The cell probably does not express acetyl transacylase
* The cell probably has malonyl transacylase activity
* The primary product of fatty acid synthase is still probably palmitate
* The cell is probably low in oxidase activity
* The cell probably still requires a dietary source of linolenate
* The cell probably does not express acetyl transacylase
Which of the following enzymes is inhibited by palmitoyl CoA?

* β-ketoacyl-ACP reductase
* 3-hydroxyacyl-ACP dehydratase
* Enoyl-ACP reductase
* Citrate translocase
* Citrate lyase
* Citrate translocase
Fatty acids are transported across the inner mitochondrial membrane in the form of

* free fatty acids
* acyl CoA
* carnitine CoA
* acyl carnitine
* triglycerides
* acyl carnitine
Where does β-oxidation occur?

* Adipocyte triglyceride globules
* Liver cytoplasm
* Smooth endoplasmic reticulum
* Mitochondrial matrix
* All of the above
* Mitochondrial matrix
The appropriate substrate for Acyl CoA dehydrogenase is

* Palmitate
* Acyl CoA
* Acetyl CoA
* Palmitoyl ACP
* Malonyl ACP
* Acyl CoA
In normal conditions, which of the following tissues would benefit LEAST from increased blood levels of acetoacetate?

* Heart
* Liver
* Brain
* Kidney
* All of the above would benefit equally
* Brain
Dietary triglycerides are transported to the liver in the form of

* Micelles
* Chylomicrons
* Very low density lipoproteins
* Low density lipoproteins
* High density lipoproteins
* Chylomicrons
The majority of bile salts released by the gall bladder are

* Excreted in the feces
* Metabolized by bacteria in the colon
* Reabsorbed and transported in the portal circulation for reuse
* Reabsorbed and transported in the lymphatics
* Reabsorbed, metabolized in the liver and excreted in the kidneys
* Reabsorbed and transported in the portal circulation for reuse
Bile salts consist of

* Polypeptides with many glutamate residues
* Cholesterol complexed with glutamate
* Biliverdin complexed with bilirubin
* Cholate complexed with glycine or taurine
* Cholate complexed with threonine or cysteine
Cholate complexed with glycine or taurine
Which of the following are considered to be essential fatty acids?
a) Arachidonate b) Linolenate c) Linoleate d) Oleate e) Palmitate f) Stearate

* a, b and c
* a, b and d
* a, b and f
* b, c and d
* b, c and e
* a, b and c
Taurocholate and glycocholate are involved in the absorption of

* Sugars
* Amino acids
* Fatty acids
* Nucleic acids
* Glycerol
* Fatty acids
Activated lipase

* consumes ATP to phosphorylate glycerol
* breaks acyl groups from triglycerides
* converts ATP into cAMP
* is a mitochondrial enzyme involved in fatty acid synthesis
* is a component of fatty acid synthase
* breaks acyl groups from triglycerides
Dietary triglycerides are transported to the liver as a component of

* Chylomicrons
* High density lipoproteins
* Low density lipoproteins
* Very low density lipoproteins
* Micelles
* Chylomicrons
What is the fate of most bile salts following their function in the small intestine?

* Excretion in the unmetabolized form in the feces
* Excretion in the urine
* Reabsorption and transport in the lymphatics
* Reabsorption and transport in the portal circulation
* Destruction by bacteria in the large intestine
* Reabsorption and transport in the portal circulation
Which of the following enzymes breaks triacylglycerol into 4 fragments?

* Lipase
* Glycerol kinase
* Acyl CoA dehydrogenase
* Acyl CoA synthase
* β-ketothiolase
* Lipase
Dietary lipids are needed for good health because they

* Facilitate amino acid absorption in the gut
* Contain essential fatty acids
* Provide most of our dietary source of energy
* Are needed for absorption of fat soluble vitamins
* Are needed for bile synthesis
* Contain essential fatty acids
An elevation of which of the following would NOT be expected to affect plasma free fatty acid levels?

* Albumin
* Parathormone
* Insulin
* Chylomicrons
* Parathormone
Dietary fatty acids initially enter the circulatory system as

* Fatty acids
* High density lipoproteins
* Chylomicrons
* Low density lipoproteins
* Very low density lipoproteins
* Chylomicrons
A lipoprotein containing Apo48, Apo CII and ApoE would be a

* Chylomicron
* Chylomicron remnant
* VLDL
* LDL
* HDL
* Chylomicron
Which apoprotein is responsible for stimulating lipoprotein lipase?

* ApoB48
* ApoB-100
* ApoD
* ApoE
* ApoCII
* ApoCII
Dietary cholesterol is packaged in the liver and released to the circulation in the form of

* Bile
* HDL
* LDL
* VLDL
* Bile salts
* VLDL
Which of the following is NOT a primary function of high density lipoprotein?

* Scavenge cholesterol from dying cells
* Transport fatty acids to the cells of the body
* Donate ApoCII to VLDLs
* Donate ApoE to chylomicrons
* Donate ApoE to VLDLs
* Transport fatty acids to the cells of the body
Which of the following effects does dietary fat have on gastric emptying?

* Fat stimulates enterogastrone release, which stimulates gastric emptying
* Fat stimulates enterogastrone release, which inhibits gastric emptying
* Fat initiates the enterogastric reflex, which inhibits gastric emptying
* Fat initiates the enterogastric reflex, which stimulates gastric emptying
* Fat inhibits secretin release, which decreases gastric emptying
* Fat stimulates enterogastrone release, which inhibits gastric emptying
What is the fate of most bile salts after their secretion into the small intestine?

* Reabsorption in the portal circulation and eventual reuse by the liver
* Reabsorption in the central lacteal and excretion in the urine
* Excretion in the feces
* Destruction by bacteria in the large intestine and excretion as bilirubin
* Conversion to biliverdin in the small intestine, followed by excretion in the feces
* Reabsorption in the portal circulation and eventual reuse by the liver
What do testosterone, cortisol and thyroxin all have in common?

* They are all derived from cholesterol
* They are all derived from amino acids
* Each acts on only one target tissue
* They are all regulated by secretions of the anterior pituitary
* They are all regulated by secretions of the posterior pituitary
* They are all regulated by secretions of the anterior pituitary
Which of the following hormones is NOT a cholesterol derivative?

* Cortisol
* Estradiol
* Progesterone
* Testosterone
* Thyroxin
* Thyroxin
Which of the following is an intermediate during cholesterol synthesis?

* Choline
* Squalene
* Phosphatidate
* Tyrosine
* Sphingosine
* Squalene
The primary effect of cholesterol on mammalian cell membranes is

* it decreases membrane fluidity.
* it prevents flip-flopping of lipids across the bilayer.
* it participates in cell-cell recognition.
* to regulate fluidity in the inner leaflet.
* to stabilize proteins as they flip-flop across the membrane
it decreases membrane fluidity.
Dietary cholesterol is packaged in the liver and released to the circulation in the form of

* Bile
* HDL
* LDL
* VLDL
* Bile salts
* VLDL
The primary regulatory enzyme for cholesterol synthesis is

* Squalene synthase
* HMG-CoA synthase
* HMG-CoA reductase
* Squalene monoxygenase
* Diaphorase
* HMG-CoA reductase
The primary route for decreasing the cholesterol content of the body is by

* Catabolism to coprostanol in liver cells
* Secretion as biles acids
* Catabolism to acetyl CoA for energy production
* Conversion to squalene
* Conversion to mevallonic acid
* Secretion as biles acids
Which of the following is a bile acid?

* Chenodeoxycholic acid
* Mevallonic acid
* Phosphatidyl choline
* Coprostanol
* Lanosterol
* Chenodeoxycholic acid
The rate limiting enzyme for cholesterol synthesis is

* HMG-CoA synthase
* HMG-CoA lyase
* HMG-CoA reductase
* Acyl carnitine transferase
* Citrate lyase
* HMG-CoA reductase
Desmolase DIRECTLY produces

* Pregnenolone
* Progesterone
* Testosterone
* Cortisol
* All of the above
* Pregnenolone
Which of the following describes the effect of untreated diabetes mellitus on fat metabolism?

* Triglyceride catabolism is decreased due to the elevated blood glucose level
* Triglyceride catabolism is enhanced in adipocytes
* Cholesterol storage is increased in Kupffer cells
* Cholesterol storage is increased in hepatocytes
* Triglyceride storage is enhanced in hepatocytes
* Triglyceride catabolism is enhanced in adipocytes
Which of the following would be expected to be elevated in untreated diabetic acidosis?

* Calcium
* Chloride
* Bicarbonate
* Ketones
* Sodium
* Ketones
During a prolonged fast the brain will begin using ________ as it's primary energy source.

* Glucose
* β-hydroxybutyrate
* Citrate
* Acetone
* Glycerol
β-hydroxybutyrate
Which of the following would NOT be expected as a symptom of untreated diabetes mellitus?

* Ketosis
* Acidosis
* Ketonuria
* Glucosuria
* Alkalosis
* Alkalosis
Which of the following vitamins is part of a cofactor for transaminase?

* Niacin
* Folate
* Riboflavin
* Pyridoxine
* Thiamine
* Pyridoxine
The first step in catabolism of most amino acids is

* conversion of the carboxyl group to acetyl CoA
* removal of the amino group
* production of urea
* breaking of any ringed structures
* conversion of the R group to glucose
* removal of the amino group
The coenzyme which is used to stabilize transaminase intermediates is

* Biotin
* Pyridoxal phosphate
* Flavin mononucleotide (FMN)
* Coenzyme A
* Thiamin pyrophosphate
* Pyridoxal phosphate
Which of the following is both a ketogenic and glucogenic amino acid?

* Leucine
* Lysine
* Tyrosine
* Aspartate
* Proline
* Tyrosine
Why is it important that oxaloacetate can be transaminated?

* This is how the amino group is removed from amino acids
* It is the reaction which produces urea
* Without this reaction we would require much more dietary aspartate for urea production
* Transamination produces carbamoyl phosphate
* This reaction allows amino acids to be glucogenic
* Without this reaction we would require much more dietary aspartate for urea production
A compound which inhibited transaminases would

* interfere with catabolism of all amino acids
* tend to increase cellular glutamate concentration
* not affect serine catabolism
* increase NH4+ production in cells
* All of the above
* not affect serine catabolism
Which of the following statements is correct?

* Gram for gram, protein stores more energy than fat
* Amino acid catabolism cannot supply carbons for fatty acid synthesis
* Pyridoxal phosphate stabilizes carboxyl groups during amino acid catabolism
* Carbamoyl phosphate is synthesized in mitochondria
* Argininosuccinate synthetase produces two ATPs for every urea molecule
* Carbamoyl phosphate is synthesized in mitochondria
Which of the following is NOT an entry point for amino acid carbons into energy metabolism?

* Citrate
* α-ketoglutarate
* Succinyl CoA
* Oxaloacetate
* All of the above are entry points
* Citrate
Which of the following is particularly important in amino acid metabolism?

* Pyridoxine
* Pantothenate
* Riboflavin
* Cobalamin
* α-Tocopherol
* Pyridoxine
Which amino acid is the product for the transamination reaction which uses oxaloacetate and glutamate as substrate?

* Leucine
* Aspartate
* Glutamate
* Glycine
* Glutamine
* Aspartate
During metabolic acidosis there is a significant increase in urinary ammonia. This ammonia is present in the blood as a part of

* glutamate
* glutamine
* creatinine
* urate
* urea
* glutamine
Which of the following is particularly important in amino acid metabolism?

* Pyridoxine
* Pantothenic Acid
* Riboflavin
* Cobalamin
* α-Tocopherol
* Pyridoxine
Which of the following compounds is a source of methyl groups for biosynthetic reactions?

* Tetrahydrofolate
* Valine
* Glycine
* Leucine
* Isoleucine
* Tetrahydrofolate
Which of the following amino acids can contribute both to ketone body formation and gluconeogenesis?

* Leucine
* Lysine
* Isoleucine
* Valine
* Cysteine
* Isoleucine
Which of the following enzymes does NOT directly "free" an amine group from an amino acid?

* Aspartate aminotransferase
* Glutamate dehydrogenase
* Serine dehydratase
* Threonine dehydratase
* All of the above produce free ammonium
* Aspartate aminotransferase
During fasting, proteins are catabolized in order to produce

* β-amino acids
* α-keto acids
* Carbamoyl phosphate
* Arginine
* Citrulline
* α-keto acids
One initial product of both transaminases and deaminases is

* Glutamate
* α-ketoglutarate
* α-keto acid
* %alpha;-amino acid
* Urea
* α-keto acid
The majority of amino acids taken from the amino acid pool each day will be used for

* Protein catabolism
* Protein synthesis
* Gluconeogenesis
* Neurotransmitter synthesis
* Urea synthesis
* Protein synthesis
Which of the following is a proteolytic enzyme which activates other proteolytic enzymes?

* Enterokinase
* Pepsin
* Trypsin
* All of the above
* B and C, but NOT A
* All of the above
Alanine transaminase (GPT) is particularly important in which tissue?

* Liver
* Muscle
* Brain
* Small intestine
* A and B
* A and B
Plasma glutamine is primarily taken up by

* Liver
* Brain
* Small intestine
* Kidney
* Pancreas
* Kidney
The ability of skeletal muscle to produce alanine requires the presence of glutamate and which of the following α-keto acids?

* Pyruvate
* Oxaloacetate
* Acetoacetate
* Acetate
* Malate
* Pyruvate
Not all amino acids for protein synthesis need to be acquired from the diet, and are instead synthesized within our cells primarily using what carbon source?

* Fatty acids
* Glucose
* Carbon dioxide
* Tetrahydrofolate
* Nucleic acids
* Glucose
The enzyme which directly produces urea is

* Arginase
* Urease
* Argininosuccinase
* Ornithine transcarbamylase
* Uricase
* Arginase
Serotonin is synthesized from

* Phenylalanine
* Tyrosine
* Tryptophan
* Glutamate
* Threonine
* Tryptophan
One initial product of both transaminases and deaminases is

* Glutamate
* α-ketoglutarate
* α-keto acid
* %alpha;-amino acid
* Urea
* α-keto acid
The majority of amino acids taken from the amino acid pool each day will be used for

* Protein catabolism
* Protein synthesis
* Gluconeogenesis
* Neurotransmitter synthesis
* Urea synthesis
* Protein synthesis
Which of the following is a proteolytic enzyme which activates other proteolytic enzymes?

* Enterokinase
* Pepsin
* Trypsin
* All of the above
* B and C, but NOT A
* All of the above
Nitrogen in blood is primarily present as a component of proteins and ____________.

* Urea
* Uric acid
* Free amino acids
* Hypoxanthine
* Xanthine
* Urea
Which of the following compounds is the DIRECT precursor of urea?

* Glutamate
* Aspartate
* Citrulline
* Ornithine
* Arginine
* Arginine
When the α amino group is removed from an amino acid it

* can come off in the form of ammonium ion
* can be used to convert α-ketoglutarate to glutamate
* will usually end up being incorporated into urea
* All of the above
* B and C only
* All of the above
The enzyme which directly produces urea is

* Arginase
* Urease
* Argininosuccinase
* Ornithine transcarbamylase
* Uricase
* Arginase
One of the products of glutamate dehydrogenase is ammonium ion. This ammonium ion is used by which enzyme?

* Ornithine transcarbamylase
* Argininosuccinate synthase
* Carbamoyl phosphate synthetase
* Arginase
* Hexokinase
* Carbamoyl phosphate synthetase
The donor for the second NH3 group (last one to be added) in the urea cycle is

* Aspartate
* Fumarate
* Oxaloacetate
* Carbamoyl phosphate
* Malate
* Aspartate
What enzyme produces urea?

* Carbamoyl phosphate synthase
* Argininosuccinase
* Argininosuccinate synthase
* Arginase
* Glutamate dehydrogenase
* Arginase
What is the primary waste product of amino acid metabolism in birds?

* Urea
* Ammonia
* Urine
* Uric acid
* Fumarate
* Uric acid
A compound which inhibited transaminases would

* interfere with catabolism of all amino acids
* tend to increase cellular glutamate concentration
* not affect serine catabolism
* increase NH4+ production in cells
* All of the above
* not affect serine catabolism
The enzyme which produces urea as one of it's products is

* Argininosuccinase
* Argininosuccinate synthetase
* Ornithine transcarbamylase
* Arginase
* Carbamoyl phosphate synthetase
* Arginase
Which molecule is the "first" substrate in the urea cycle, and regenerated by the last reaction in the cycle?

* Arginine
* Citrulline
* Oxaloacetate
* Argininosuccinate
* Ornithine
* Ornithine
The two nitrogens contained in urea originate from

* ammonia
* ammonia and glutamate
* ammonia and glutamine
* ammonia and aspartate
* carbamoyl phosphate and glutamine
* ammonia and aspartate
The cost to a liver cell to produce one urea molecule is

* 2 ATP equivalents
* 4 ATP equivalents
* 6 ATP equivalents
* 12 ATP equivalents
* 38 ATP equivalents
* 4 ATP equivalents
Ammonia is directly produced by

* Carbamoylphosphate synthase
* Glutamate dehydrogenase
* Aspartate amino transferase
* Glutamate-Pyruvate transaminase
* Arginase
* Glutamate dehydrogenase
Where is urea primarily formed?

* Skeletal muscle
* Liver
* Proximal tubule of the kidney
* Distal tubule of the kidney
* Brain
* Liver
Which of the following is FALSE regarding ammonia?

* Glutamine is a source of ammonia production in the kidney
* Ammonia is toxic to neural function
* Glutamate dehydrogenase is used to produce free ammonia from glutamate deamination
* Carbamoyl phosphate is deaminated to form aspartate and ammonia
* The primary source for ammonia production in the body is from the amine groups of amino acids
* Carbamoyl phosphate is deaminated to form aspartate and ammonia
A chemical which inhibits protein phosphorylation would

* increase phosphorylase kinase activity
* increase net glycogen synthesis
* increase net glycogen breakdown
* increase phosphorylase A activity
* All of the above are correct
* increase net glycogen synthesis
Which of the following would be expected to be occurring at three hours of a fast?

* Increased fat synthesis
* Decreased glycogen in the liver
* Elevated plasma glucose
* Inhibition of gluconeogenesis
* Increased brain consumption of ketones
* Decreased glycogen in the liver
Which of the following pairs of hormones BOTH increase cAMP, glycogenolysis and lipolysis?

* Insulin and calcitonin
* Glucagon and epinephrine
* Aldosterone and estradiol
* Parathormone and epinephrine
* Insulin and epinephrine
* Glucagon and epinephrine
Surgical removal of which of the following would lower the blood glucose level in a patient with diabetes mellitus?

* Testes
* Thyroid gland
* Parathyroid gland
* Anterior pituitary
* Posterior pituitary
* Anterior pituitary
Glucagon promotes hyperglycemia, primarily by stimulating

* Growth hormone secretion
* Muscle glycogenolysis
* Liver glycogenolysis
* Brain glycolysis
* Renal retention of filtered glucose
* Liver glycogenolysis
Which of the following is LEAST likely to be taking place in a person just before dinner if they last ate that morning?

* Glycogen synthesis
* β-oxidation
* Urea synthesis
* Gluconeogenesis
* Formation of cAMP in hepatocytes
* Glycogen synthesis
Just prior to eating breakfast, your body will be

* Storing fat
* Catabolizing liver glycogen
* Suppressing gluconeogenesis
* Exhibiting elevated plasma glucose levels
* Synthesizing muscle protein
* Catabolizing liver glycogen
Which hormone stimulates glucose uptake and protein synthesis by skeletal muscle, and inhibits triglyceride catabolism in adipocytes?

* Glucagon
* Insulin
* Epinephrine
* Cortisol
* Thyroxine
* Insulin
In the presence of insulin

* Glycogen synthase is in the D form
* Glycogen synthase is in the I form
* Glycogen phosphorylase is in the A form
* Phosphorylase kinase kinase is in the active form
* Synthase kinase is in the active form
* Glycogen synthase is in the I form
What effect does insulin have on muscle cells?

* Inhibit glucose uptake
* Stimulate protein synthesis
* Stimulate triglyceride synthesis
* Inhibit gluconeogenesis
* All of the above
* Stimulate protein synthesis
Which of the following is INCORRECT regarding glucagon?

* Glucagon release is stimulated by amino acids in plasma
* Glucagon stimulates gluconeogenesis in the liver
* Glucagon stimulates amino acid uptake by the liver
* Glucagon stimulates ketone synthesis in adipocytes
* Glucagon stimulates cAMP formation in target cells
* Glucagon stimulates ketone synthesis in adipocytes
High insulin levels in the blood

* Inhibit gluconeogenesis in muscle
* Stimulate glucose uptake by the liver
* Activate lipoprotein lipase in the vascular system
* Stimulate hormone-sensitive lipase in adipocytes
* Inhibit amino acid uptake by the liver
* Activate lipoprotein lipase in the vascular system
Glucagon

* Release is stimulated by amino acids in the blood
* Stimulates gluconeogenesis in the liver
* Increases amino acid uptake by the liver
* Does not affect glucose transporters
* All of the above are correct
* All of the above are correct
All of the following statements about the insulin receptor and other growth factor receptors are correct except for which one?

* Signaling by these receptors requires cytoplasmic second messengers
* The receptors are protein kinases that phosphorylate tyrosine residues
* A cascade of Ser/Thr protein kinases participates in signaling by many of these receptors
* The receptors are located in the plasma membrane
* Binding of hormone to receptors can regulate gene expression by affecting the phosphorylation of nuclear proteins
* Signaling by these receptors requires cytoplasmic second messengers
Which polypeptide increases glucose entry into adipocytes and inhibits Hormone Sensitive Lipase in those cells?

* Insulin
* Glucagon
* Calcitonin
* Parathyroid hormone
* 1,25 dihydroxy Vitamin D3
* Insulin
Long term exposure to this hormone will increase glycolytic enzyme levels in liver cells:

* Insulin
* Glucagon
* Calcitonin
* Parathyroid hormone
* 1,25 dihydroxy Vitamin D3
* Glucagon
Which of the following is NOT true of insulin?

* It is a polypeptide hormone
* It is secreted by pancreatic Beta cells
* It inhibits gluconeogenesis in the liver
* It inhibits triglyceride synthesis by adipocytes
* It stimulates amino acid uptake by muscle cells
* It inhibits triglyceride synthesis by adipocytes
Insulin receptors also contain

* Glucokinase
* Tyrosine kinase
* Adenylate cyclase
* Phospholipase C
* Glucose transporters
* Tyrosine kinase
During the fed state, blood glucose will be taken up by

* Brain
* Liver
* Adipocytes
* Myocytes
* All of the above
* All of the above
Which of the following is an effector?

* Acetylcholine
* Adenylate cyclase
* Calcium
* Inositol triphosphate
* Nicotinic cholinergic receptor
* Adenylate cyclase
Purines and pyrimidines are important because

* some of them are used for energy transport
* they inhibit second messenger formation
* they metabolize coenzymes
* they are used in DNA synthesis
* More than one of the above
* More than one of the above
Inhibiting ribonucleotide reductase would

* increase the concentration of disulfide bonds in thioredoxin
* decrease the concentration of DNA precursors
* decrease the concentration of RNA precursors
* decrease total ATP levels
* All of the above
* decrease the concentration of DNA precursors
The key regulatory point for the synthesis of CTP is

* the rate of formation of orotic acid from aspartate and carbamoyl phosphate
* the rate of formation of IMP
* ribose-5-phosphate availability
* the rate of production of the purine base
* TTP availability
* the rate of formation of orotic acid from aspartate and carbamoyl phosphate
Inhibition of guanine phosphoribosyl transferase will

* tend to increase GTP levels
* help prevent the formation of kidney stones
* tend to decrease uric acid concentration in the urine
* increase energy demands on the cell for the synthesis of new purine bases
* All of the above
* increase energy demands on the cell for the synthesis of new purine bases
The primary metabolite of cytosine and uridine metabolism found in the urine is

* methylmalonate
* malonate
* uric acid
* Coenzyme A
* PRPP
* malonate
A mutation of the gene for thioredoxin causes insertion of glycine for cysteine. Which of the following statements is correct?

* The mutation was a transversion
* UDP levels will probably fall
* dUDP levels will probably fall
* Thioredoxin reductase activity will probably increase
* All of the above are correct
* UDP levels will probably fall
UMP

* contains a pyrimidine ring
* is formed in the reaction catalyzed by orotidylate pyrophosphorylase
* synthesis is inhibited by azaserine
* is used by thioredoxin reductase to make dUMP
* synthesis requires more ATP equivalents than does IMP synthesis
* contains a pyrimidine ring
Inhibition of which of the following enzymes will DECREASE UMP synthesis?

* Aspartate transcarbamylase
* Orotidylate pyrophosphorylase
* Ribose phosphate pyrophosphokinase
* Inhibition of any of the above enzymes would inhibit UMP synthesis
* None of the above enzymes affect UMP synthesis
* Inhibition of any of the above enzymes would inhibit UMP synthesis
Which of the following enzymes is inhibited by dATP, thereby decreasing deoxynucleotide synthesis?

* IMP dehydrogenase
* GMP synthetase
* Ribonucleotide reductase
* Aspartate transcarbamylase
* Adenylosuccinate lyase
* Ribonucleotide reductase
High levels of ATP will

* inhibit formation of XMP from IMP
* stimulate conversion of IMP to adenylosuccinate
* stimulate conversion of PRPP to 5'-phosphoribosylamine
* stimulate conversion of XMP to GMP
* inhibit formation of GTP
* stimulate conversion of XMP to GMP
Which of the following is inhibited by both purines and pyrimidines?

* Ribose phosphate pyrophosphokinase
* Amidophosphoribosyl transferase
* Aspartate transcarbamylase
* Orotodylate pyrophosphorylase
* Ribonucleotide reductase
* Ribose phosphate pyrophosphokinase
A compound called caged-ATP consists of ATP with an auxiliary prosthetic group connected. The group is released when it is hit by a specific wavelength of light, causing a sudden increase in ATP availability. Which of the following would decrease in activity when a cell loaded with caged-ATP is suddenly illuminated?

* Aspartate transcarbamylase
* Adenylosuccinate synthetase
* GMP synthetase
* Ribonucleotide reductase
* All of the above would decrease in activity in the presence of high ATP levels
* Adenylosuccinate synthetase
Which of the following would you expect to see in a patient after they begin taking allopurinol?

* Uric acid levels in their urine would decrease
* Adenylosuccinate synthetase and IMP dehydrogenase activity would probably be decreased indirectly
* Xanthine levels would tend to increase
* Malonate levels in urine would NOT be affected
* All of the above would be expected
* All of the above would be expected
Catabolism of AMP or GMP results in the final product named

* IMP
* Hypoxanthine
* Xanthine
* Uric acid
* Urea
* Uric acid
Which of the following removes the -OH group from the second carbon of ribose?

* Ribonucleotide reductase
* Amidophosphoribosyl transferase
* Thioredoxin reductase
* Phosphopentose isomerase
* Transketolase
* Ribonucleotide reductase