Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
190 Cards in this Set
- Front
- Back
|
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
|
