Final Exam Chapter Questions

Even though one of them is not in the cycle, all of the following are important enzymes of the urea cycle EXCEPT A. Carbamoylphosphate synthetase II in the cytosol B. Ornithine transcarbamylase in the mitochondria C. Argininosuccinate synthetase in the cytosol D. Argininosuccinate lyase in the cytosol E. Arginase in the cytosol

Answer: A. Carbamoylphosphate synthetase II in the cytosol. Chapter 38, Objective 12: Know the substrates, products, and five enzymes of the urea cycle. Which compartments are involved? What tissues are involved?

Concerning the synthesis of triacylglycerol in adipose tissue and in the fed state, all of the following are true EXCEPT A. Glycerol kinase is activated by phosphatases B. Lipoprotein Lipase is activated by insulin C. Glut4 in the membrane is increased by insulin D. Glycolysis is activated by insulin to produce energy and dihydroxyacetone phosphate E. Hormone sensitive lipase is inhibited by insulin

Answer: A. Glycerol kinase is activated by phosphatases. Chapter 36, Objectives 10: What are the pathways for the synthesis of triacylglycerol in adipose from glucose and free fatty acids? How is the production of glycerol phosphate regulated?

All of the following are true for the glutamate dehydrogenase reaction EXCEPT A. Its substrates can be aspartate + H2O + NAD+ B. Its substrates can be α-ketoglutarate + NADH + NH4+ +H+ C. It adds NH4+ to the solution when the concentration of NH4+ is low D. It removes NH4+ from the solution when the concentration of NH4+ is high E. It is an anaplerotic reaction for the TCA cycle

Answer: A. Its substrates can be aspartate + H2O + NAD+. Chapter 38, Objective 8: Be able to write the glutamate dehydrogenase reaction. Is this reaction readily reversible?

As one enters the fasting state, liver glycolysis is inhibited while gluconeogenesis is activated. All of the following are important in this process EXCEPT A. Protein kinase A activates phosphofructokinase-2 and the concentration of fructose-2,6-bisphosphate rises B. In the absence of fructose-2,6-bisphosphate, fructose-1,6-bisphosphatase is active C. Protein kinase A phosphorylates pyruvate kinase so that phosphoenolpyruvate must become 2-phosphoglycerate and eventually glucose D. Energy is provided by free fatty acids that are mobilized, enter the mitochondria, and are oxidized by b-oxidation E. The increased Acetyl CoA activates pyruvate carboxylase so that pyruvate can be used as a substrate

Answer: A. Protein kinase A activates phosphofructokinase-2 and the concentration of fructose-2,6-bisphosphate rises. Chapter 36, Objective 14: Glycolysis does not function when gluconeogenesis is functioning. What factors turn on gluconeogenesis and turn off glycolysis?

If a portion of the brain is producing a lot of ammonium ions, all of the following may occur EXCEPT A. Using gluconeogenesis, the brain could produce α-ketoglutarate B. α-ketoglutarate could react with NH4+ + NADH + H+ to form glutamate using glutamate dehydrogenase C. Glutamate could react with ATP + NH4+ to form glutamine using the enzyme glutamine synthetase D. Glutamine could travel to the liver where glutaminase could hydrolyze the amide nitrogen producing free NH4+ for urea synthesis E. In the liver, glutamate could undergo gluconeogenesis after transferring its α-amino group to oxaloacetic acid

Answer: A. Using gluconeogenesis, the brain could produce α-ketoglutarate. Chapter 38, Objective 11: When excess NH4+ is produced in most cells of the body, it can be combined with glutamate and transported to the liver where it is released as free NH4+. Name the two enzymes and the intermediate in this process.

Starting with the ornithine transcarbamoylase reaction, the order in which intermediates in the urea cycle would occur is A. citrulline, argininosuccinate, arginine, ornithine B. argininosuccinate, citrulline, arginine, ornithine C. argininosuccinate, arginine, citrulline, ornithine D. citrulline, arginine, argininosuccinate, ornithine E. citrulline, arginine, ornithine, argininosuccinate

Answer: A. citrulline, argininosuccinate, arginine, ornithine. Chapter 38, Objective 12: Know the substrates, products, and five enzymes of the urea cycle. Which compartments are involved? What tissues are involved?

All of the following are true for the enzyme abbreviated AST EXCEPT A. Is sometimes called aspartate aminotransferase B. Can produce glutamate if NADPH and α-ketoglutarate are substrates C. Can produce α-ketoglutarate and aspartate D. Can produce glutamate and oxaloacetate E. The Keq = 1

Answer: B. Can produce glutamate if NADPH and α-ketoglutarate are substrates. Chapter 38, Objectives 3 and 4: What is another name for transamination reactions? Be able to write a reaction for AST, ALT, or any other transamination reaction. What is the approximate Keq for these reactions?

In the fasting state, much less glucose is used in skeletal muscle than in the fed state. All of the following help to explain this EXCEPT A. Increased mobilization of free fatty acids B. Increased malonyl CoA C. Increased ATP produced by β-oxidation D. Low insulin and low AMP results in low phosphofructokinase-1 activity E. Hexokinase is inhibited by high concentrations of glucose-6-phosphate

Answer: B. Increased malonyl CoA. Chapter 36, Objectives 18: Explain how increased fatty acid oxidation and decreased insulin spares blood glucose by muscle in the fasting and resting state.

All of the following are major sources of free ammonia in the liver, muscle and other tissues EXCEPT A. The glutamic acid dehydrogenase reaction B. Most transamination reactions C. The deamination of amino acids D. Glutaminase and asparaginase reactions E. The urease reaction in the gut

Answer: B. Most transamination reactions. Chapter 38, Objective 7: What are the major sources of free ammonia in the liver, muscle and other tissues?

Concerning the storage of glucose in the liver, all of the following are true EXCEPT A. Regulated by glucose concentration and insulin concentration B. Occurring when both glycogen synthase and glycogen phosphorylase are both phosphorylated C. Not part of a futile cycle because when glycogen synthase is activated, glycogen phosphorylase is inactivated D. Inhibited by glucagon and epinephrine which both activate the cAMP cascade E. Limited to times when glucose concentration is high because the Km (S0.5) of glucokinase is about 7 mM

Answer: B. Occurring when both glycogen synthase and glycogen phosphorylase are both phosphorylated. Chapter 36, Objective 1: Describe the pathway for the storage of glucose in the liver in the fed state? How is this pathway regulated.? Are there any possible futile cycles prevented?

All of the following statements about the synthesis of nonessential amino acids are true EXCEPT A. The carbon structure can usually be made from glucose B. The carbon structure can usually be made from fatty acids C. The amino group can be transferred from glutamate D. The amino group can originate from free ammonium ion if glutamate dehydrogenase and a transaminase are used E. The amino group can originate from alanine if two transaminase reactions are used

Answer: B. The carbon structure can usually be made from fatty acids. Chapter 38, Objective 9: Glutamate is important in the synthesis of nonessential amino acids. How does glutamate acquire the amino groups for this purpose?

All of the following occur when muscle protein is catabolized during a fast EXCEPT A. Some of the carbon skeletons are used for energy in the muscle following transamination B. The nitrogen of some amino acids is transferred to pyruvate and forms glutamine for export to the liver C. The nitrogen of some amino acids ends up as the amide nitrogen of glutamine before export to other tissues D. Some of the nitrogen ends up as ammonium in the urine E. Most of the nitrogen ends up in urea synthesized in the liver

Answer: B. The nitrogen of some amino acids is transferred to pyruvate and forms glutamine for export to the liver. Chapter 38, Objective 2: When muscle protein is catabolized in muscle during a fast, what are the fates of the amino acids?

In a sedentary fasting state, skeletal muscle spares blood glucose. All of the following are important in this process EXCEPT A. By using mostly fatty acid, muscle needs less glucose for energy production B. At low insulin levels, fatty acid mobilization is increased C. At low insulin levels, acetyl CoA carboxylase is activated D. The more energy produced from fatty acids, the less glucose needs to be oxidized E. In a sedentary fasting state, most of the glut4 transporters have been removed from the muscle cell membrane

Answer: C. At low insulin levels, acetyl CoA carboxylase is activated. Chapter 36, Objective 18: Explain how increased fatty acid oxidation and decreased insulin spares blood glucose by muscle in the fasting and resting state.

All of the following statements about the regulation of fatty acid mobilization (release from adipose) are true EXCEPT A. The control enzyme is called hormone sensitive lipase B. Insulin activates a protein phosphatase that removes a phosphate from hormone sensitive lipase C. Cortisol inhibits hormone sensitive lipase using the cAMP cascade D. Epinephrine activates hormone sensitive lipase using the cAMP cascade E. Glucagon activates hormone sensitive lipase using the cAMP cascade

Answer: C. Cortisol inhibits hormone sensitive lipase using the cAMP cascade. Chapter 36, Objective 15: What is the control enzyme for the release of free fatty acids during a fast and how is this enzyme regulated?

All of the following are true statements about the fate of the product of the fatty acid synthase complex in the fed state EXCEPT A. Palmitate is activated to palmitoyl CoA B. Much of the palmitoyl CoA is elongated and desaturated in the endoplasmic reticulum C. Fatty acyl CoA combines with diacylglycerol phosphate to form phosphatidic acid D. Phosphatidic acid is dephosphorylated to diacylglycerol, which combines with acyl CoA to form triacylglycerol E. Triacylglycerol combines with Apo B-100, cholesterol, cholesterol esters, and glycerophospholipids to form a VLDL

Answer: C. Fatty acyl CoA combines with diacylglycerol phosphate to form phosphatidic acid. Chapter 36, Objective 7: What happens to the product of the fatty acid synthase complex before it is found in the blood?

Di Beatty, who has type I diabetes and has developed ketoacidosis. Her blood contains less insulin than it should and more stress hormones that it should. These hormone levels explain all of the following EXCEPT A. Some of the excess fatty acids released for adipose are converted to VLDL so the liver releases more VLDL than normal B. The lipoprotein lipase of adipose is not as active as it should be so VLDL and chylomicrons are not catabolized at a normal rate C. Glucose enters muscle and adipose tissue at a faster rate but is not utilized as it should so blood glucose rises D. Gluconeogenesis is more activated and muscle protein is being catabolized which also causes blood glucose to rise E. More acetyl CoA is being produced than can be used so it is converted to ketone bodies

Answer: C. Glucose enters muscle and adipose tissue at a faster rate but is not utilized as it should so blood glucose rises. Chapter 36, Objectives 20: Concerning Di Beatty, who has type I diabetes and has developed ketoacidosis: On a molecular level, explain why she has opalescent serum. Why does she have high blood glucose? Why does she have ketonemia?

When urea is synthesized in the liver, all of the following may be occurring EXCEPT A. Glutamate may be synthesized from α-ketoglutarate using a number of amino transferase reactions B. Aspartate may be synthesized from oxaloacetate and glutamate using AST C. Many amino acids may transfer their amino groups directly to oxaloacetate to form aspartate D. Glutamate may be synthesized using the glutamate dehydrogenase reaction if ammonium ion is in excess E. Glutamate may be providing free ammonium ion if the concentration of free ammonium ion is low

Answer: C. Many amino acids may transfer their amino groups directly to oxaloacetate to form aspartate. Chapter 38, Objective 10: Glutamate is important in the synthesis of urea. How does glutamate acquire the amino groups for this purpose? What does glutamate do with the amino groups?

All of the following occur when muscle protein is catabolized during a fast EXCEPT A. Some of the amino acids are oxidized in the muscle to produce energy B. Most of the amino acids, including large amounts of glutamine and alanine are released from muscle cells C. Most of the nitrogen atoms are incorporated into uric acid D. Gluconeogenesis uses some of the amino acids as substrates E. Some amino acids are catabolized to acetyl CoA that is used for energy

Answer: C. Most of the nitrogen atoms are incorporated into uric acid. Chapter 38, Objective 2: When muscle protein is catabolized in muscle during a fast, what are the fates of the amino acids?

This patient has a deficiency of argininosuccinate lyase and has very high concentrations of blood glutamine and ammonium ion. You could treat her with all of the following EXCEPT A. Low protein diet B. Arginine supplementation to her diet C. Oral doses of hippuric acid and phenylacetylglutamine D. Benzoic acid tablets E. Oral doses of pheylbutyrate

Answer: C. Oral doses of hippuric acid and phenylacetylglutamine. Chapter 38, Objective 15: Name 3 ways to treat argininosuccinate lyase deficiency and explain their rationale.

As a fast is prolonged, glycogenolysis becomes less important and gluconeogenesis becomes more important. All of the following are important for gluconeogenesis EXCEPT A. Pyruvate must not be converted to acetyl CoA B. Beta-oxidation produces high concentrations of acetyl CoA which activate pyruvate carboxylase C. Phosphoenolpyruvate must not be converted to 2-phosphoglycerate D. β-oxidation produces high concentrations of acetyl CoA which inhibit pyruvate dehydrogenase E. Beta-oxidation and The TCA cycle produce NADH and FADH2, which, in turn, produces ATP

Answer: C. Phosphoenolpyruvate must not be converted to 2-phosphoglycerate. Chapter 36, Objective 17: Besides providing ATP, how does increased b oxidation enable gluconeogenesis?

During fasting, the blood glucose is maintained by the liver. Because of low insulin to glucagon ratios, all of the following contribute to this process EXCEPT A. The cAMP cascade is active so phosphorylase b is converted to phosphorylase a B. Glycerol is available for gluconeogenesis C. Phosphofructokinase-1 and phosphofructokinase-2 are both active D. Β-oxidation and the TCA cycle are providing energy for gluconeogenesis E. High acetyl CoA concentrations activating pyruvate carboxylase and inhibiting pyruvate dehydrogenase

Answer: C. Phosphofructokinase-1 and phosphofructokinase-2 are both active. Chapter 36, Objective 12: What pathways provide blood glucose during fasting? Why are these pathways active?

Ann Sulin who has type II diabetes. Since her insulin to glucagon is always lower than it should be for the level of blood glucose and because she has insulin resistance, all of the following are true EXCEPT A. She releases more free fatty acids than normal from adipose and some are converted to VLDL and released by the liver B. Since her adipose tissue is insulin resistant, her adipose lipoprotein lipase is not as active and she does not catabolize VLDL or chylomicrons at a normal rate C. Since she mobilizes too much free fatty acids, she is prone to develop ketoacidosis D. In addition to insulin resistance, in the fed state, she releases less insulin and at a slower rate so glucose is not removed from blood in a normal manner E. In the fasting state, gluconeogenesis produces an abnormal amount of glucose

Answer: C. Since she mobilizes too much free fatty acids, she is prone to develop ketoacidosis. Chapter 36, Objectives 21: Concerning Ann Sulin who has type II diabetes: On a molecular level, explain why she has high serum triacylglycerol. Why does she have high blood glucose? Would you expect ketoacidosis?

The fatty acid synthase requires reducing a reducing agent. This reducing agent is made by A. Pumping protons from the mitochondria B. Reduced coenzyme Q in the electron transport chain C. The pentose phosphate pathway and malic enzyme D. FADH2 and NADH produced in the mitochondria by the TCA cycle E. NADH produced by anaerobic glycolysis

Answer: C. The pentose phosphate pathway and malic enzyme. Chapter 36, Objective 4: What are the sources of the reducing agent used for the reductive biosynthesis of fatty acids?

Following a high protein meal, amino acids might be used for the synthesis of all of the following EXCEPT A. Proteins B. Essential nitrogen compounds like neurotransmitters C. Thiamine pyrophosphate D. Glucose E. Fatty acids

Answer: C. Thiamine pyrophosphate. Chapter 38, Objective 1: When more amino acids are ingested than are needed to replace protein and other nitrogenous compounds, what is their fate?

Your patient, Percy Veere, has hepatitis A so you order a set (panel) of liver functions tests. You will expect all of the following changes in the serum concentrations and reasons for the changes to be correct EXCEPT A. Aspartate aminotransferase (AST) will rise dramatically because of leakage from damaged or dead liver cells B. Alanine aminotransferase (ALT) will rise dramatically because of leakage from damaged or dead liver cells C. Total bilirubin will rise dramatically because of increased red blood cell lysis D. Alkaline phosphatase, normally tethered to the bile canaliculi, will be freed and find its way back to the blood

Answer: C. Total bilirubin will rise dramatically because of increased red blood cell lysis. Chapter 38, Objective 16: Concerning Percy Veere who has hepatitis A: What liver function tests were ordered? Why was the serum concentration of each substance increased?

Your patient, Percy Veere, has hepatitis A that results in high serum ammonium ion and glutamine concentrations. Which of the following treatments might help? Select the best answer. A. A lower protein diet would decrease nitrogen uptake and lower the ammonium ion and glutamine being formed B. Antibiotics would stop the growth of bacteria in the gut. This would lower the urease concentration of the gut and the amount of free ammonium ion formed from urea C. Lactulose was developed as an osmotic laxative and flushes bacteria from the gut, lowering the production of ammonium from urea D. All of the above are valid treatments and might help

Answer: D. All of the above are valid treatments and might help. Chapter 38, Objective 18: Concerning Percy Veere who has hepatitis A: Why would a low protein diet, antibiotics, enemas and lactulose lower his blood ammonium ion level?

When carbohydrate is converted to fatty acid in the liver. All of the following statements are true EXCEPT A. Some pyruvate is converted to acetyl CoA by pyruvate dehydrogenase B. Some pyruvate is converted to oxaloacetate by pyruvate carboxylase in the presence of high concentrations of acetyl CoA C. Acetyl CoA and oxaloacetate form citrate and the citrate leaves the mitochondria D. In the cytosol, citrate synthase produces ATP, oxaloacetate and acetyl CoA from citrate and ADP E. The oxaloacetate is converted back to pyruvate in the cytosol

Answer: D. In the cytosol, citrate synthase produces ATP, oxaloacetate and acetyl CoA from citrate and ADP. Chapter 36, Objective 3: During the conversion of glucose to fatty acid, how is pyruvate, produced from glycolysis, converted to citrate in the cytosol? In which compartment does each reaction take place?

In the fed state, insulin affects the delivery and storage of free fatty acids to adipose tissue in all of the following ways EXCEPT A. Insulin will increase the synthesis and secretion of the isoenzyme of lipoprotein lipase found in adipose tissue B. Insulin will increase the Glut4 in the adipose membrane so glucose can enter the cells faster C. Insulin will activate glycolysis so that dihydroxyacetone phosphate can be made faster D. Insulin will inhibit glycerol-3-phosphate dehydrogenase and prevent the loss of dihydroxyacetone phosphate E. Insulin inhibits the cAMP cascade in adipose so that triacylglycerol is not hydrolyzed

Answer: D. Insulin will inhibit glycerol-3-phosphate dehydrogenase and prevent the loss of dihydroxyacetone phosphate. Chapter 36, Objective 9: How does insulin affect the delivery of free fatty acid into adipose cells in the fed state?

When triacylglycerol is synthesized in adipose tissue, all of the following are true EXCEPT A. The insulin to glucagon ratio is high B. Glycerol phosphate is synthesized from glucose by glycolysis C. Fatty acids from chylomicrons or VLDL are activated to form acyl CoAs D. Phosphatidic acid is not an intermediate E. Diacylglycerol is an intermediate

Answer: D. Phosphatidic acid is not an intermediate. Chapter 36, Objective 10: What are the pathways for the synthesis of triacylglycerol in adipose from glucose and free fatty acids? How is the production of glycerol phosphate regulated?

The control enzyme for fatty acid synthesis A. Is activated by glucagon, epinephrine, and AMP B. Is inhibited by insulin and protein phosphatase C. Produces malonyl CoA and ATP D. Requires biotin as a cofactor E. Is found only in the endoplasmic reticulum

Answer: D. Requires biotin as a cofactor. Chapter 36, Objective 5: Which enzyme controls the pathway for the synthesis of fatty acids from acetyl CoA in the cytosol? How is this pathway regulated? (ignore citrate)

All of the following are true during fatty acid synthesis in the liver EXCEPT A. The concentration of insulin and glucose are both high B. The mobilization of free fatty acids from adipose is inhibited C. Acetyl CoA carboxylase and pyruvate carboxylase are both activated D. The concentration of malonyl CoA in the cytosol is very low E. Carnitine: palmitoyltransferase-1 is inhibited

Answer: D. The concentration of malonyl CoA in the cytosol is very low. Chapter 36, Objective 6: What keeps newly formed free fatty acid from entering the mitochondria in the fed state?

Concerning the products of the lipoprotein lipase reaction in the blood vessels of adipose tissue, all of the following are true EXCEPT A. The lipoprotein lipase reaction in adipose is usually activated in the fed state B. The products of the reaction are 3 fatty acids and one glycerol molecule C. The fatty acids enter the adipose cell and are activated by fatty acyl CoA synthetase D. The glycerol enters the liver and is phosphorylated by glycerol-3-phosphate dehydrogenase E. The glycerol could be used by the liver to synthesize another molecule of triacylglycerol

Answer: D. The glycerol enters the liver and is phosphorylated by glycerol-3-phosphate dehydrogenase. Chapter 36, Objective 11: What happens to the glycerol released in the lipoprotein lipase reaction in the fed state?

Starting with free ammonium ion and the carbamoyl phosphate synthetase reaction, A. carbamoyl phosphate is synthesized in the cytosol B. the nitrogen from aspartate is added to citrulline in the mitochondria C. arginase produces urea in the mitochondria D. ornithine is converted to citrulline in the mitochondria E. fumarate is produced from argininosuccinate in the mitochondria

Answer: D. ornithine is converted to citrulline in the mitochondria. Chapter 38, Objective 12: Know the substrates, products, and five enzymes of the urea cycle. Which compartments are involved? What tissues are involved?

If the pH of a solution is 7.3 and the pKa for ammonium ion is 9.3, then the ratio of [NH3]/[NH4+] would be A. 100/1 B. 10/1 C. 2/1 D. 1/10 E. 1/100

Answer: E. 1/100. Chapter 38, Objective 6: Around pH = 7.3, which is the most prevalent form, ammonia or ammonium ion? Use the pKa = 9.3 and the Henderson Hasselbalch Equation to prove it.

Alanine can provide both amino groups for urea synthesis. All of the following reactions would be used EXCEPT A. Alanine + α-ketoglutarate = pyruvate + glutamate B. Glutamate + oxaloacetate = aspartate + α-ketoglutarate C. Glutamate + NAD+ = NADH + H+ + NH4+ + α-ketoglutarate D. HCO3- + NH4+ + 2ATP = carbamoyl phosphate + 2 ADP+ 2Pi E. Aspartate + Ornithine + ATP = Argininosuccinate + AMP + PPi

Answer: E. Aspartate + Ornithine + ATP = Argininosuccinate + AMP + PPi. Chapter 38, Objective 10 and 12: Glutamate is important in the synthesis of urea. How does glutamate acquire the amino groups for this purpose? What does glutamate do with the amino groups? Know the substrates, products, and five enzymes of the urea cycle. Which compartments are involved? What tissues are involved?

All of the following are true for the enzyme abbreviated ALT EXCEPT A. It is sometimes called alanine aminotransferase B. It catalyzes a reversible reaction C. Can produce pyruvate and glutamate D. Can produce alanine and α-ketoglutarate E. Can produce NH4+, if the substrate is glutamate

Answer: E. Can produce NH4+, if the substrate is glutamate. Chapter 38, Objectives 3 and 4: What is another name for transamination reactions? Be able to write a reaction for AST, ALT, or any other transamination reaction. What is the approximate Keq for these reactions?

The control enzyme of the urea cycle is ___________ and it is regulated by ________________ A. Arginase: allosteric inhibition by urea B. Argininosuccinase lyase: allosteric inhibition by fumarate C. Argininosuccinate synthetase: allosteric inhibition by AMP D. Ornithine transcarbamoylase: allosteric activation by citrulline E. Carbamoyl phosphate synthetase-1: allosteric activation by N-acetylglutamate

Answer: E. Carbamoyl phosphate synthetase-1: allosteric activation by N-acetylglutamate. Chapter 38, Objective 13: How is the urea cycle regulated?

Assume that a lot of VLDL and chylomicrons are produced during and immediately following the meal and that the concentration of VLDL decreases to between the Km for adipose and muscle lipoprotein lipase by 8 hours after the meal. All of the following statements about lipoprotein lipase are true EXCEPT. A. The Km for adipose lipoprotein lipase is much higher than the Km of muscle lipoprotein lipase B. Eight hours following a meal, the concentration of VLDL will still be above the Km for muscle lipoprotein lipase C. Eight hours following a meal, the velocity of muscle lipoprotein lipase reaction will be between ½ Vmax and Vmax D. During a meal, insulin will increase the synthesis and secretion of adipose lipoprotein lipase E. During and for a few hours following a meal, the concentrations of blood VLDL and chylomicrons will be below 0.1 Km for adipose lipoprotein lipase

Answer: E. During and for a few hours following a meal, the concentrations of blood VLDL and chylomicrons will be below 0.1 Km for adipose lipoprotein lipase. Chapter 36, Objective 8: Compare the Km for lipoprotein lipase in heart and adipose tissue. What implications dose this have for the usage of blood triacylglycerol in the fed and fasting state?

Your patient, Percy Veere, has hepatitis A and an excess of ammonium ions. Some of those ammonium ions are generated in his brain. The normal mechanism for detoxifying ammonium ions in the brain includes all of the following EXCEPT A. α-ketoglutarate from the TCA cycle plus ammonium ion plus NADH form glutamate B. The enzyme converting α-ketoglutarate to glutamate is glutamate dehydrogenase C. Glutamate plus ATP plus ammonium ion form glutamine D. The enzyme is glutamine synthetase E. Glutamine is normally excreted in the urine at even low concentrations

Answer: E. Glutamine is normally excreted in the urine at even low concentrations. Chapter 38, Objective 17: Concerning Percy Veere who has hepatitis A: Name the enzymes and intermediates in the conversion of ammonium ion and a-ketoglutarate to glutamine in the brain.

During the progression of a prolonged fast, all of the following are true EXCEPT A. Muscle protein is broken down to provide amino acids, which are a major substrate for gluconeogenesis B. The nitrogen atoms from the amino acids that are converted to glucose or used for energy must be eliminated as urea C. More fatty acids are converted to ketone bodies D. The brain uses a constant amount of energy that it gets from either glucose or ketone bodies E. More brain energy supplied by ketone bodies means less brain energy has to be supplied from amino acids and more urea has to be made

Answer: E. More brain energy supplied by ketone bodies means less brain energy has to be supplied from amino acids and more urea has to be made. Chapter 38, Objective 14: How is the production of urea during a fast related to the need for blood glucose and the catabolism of muscle protein? How does the production of ketone bodies fit in?

During the fasting state, the insulin to glucagon ratio is low. In the liver, all of the following result EXCEPT A. The cyclic-AMP cascade is active and cAMP phosphodiesterase is inhibited B. cAMP combines with the regulatory subunits of protein kinase A C. Protein kinase A is activated and this inhibits glycolysis and glycogen synthesis D. Protein kinase A is activated and this activates gluconeogenesis and glycogenolysis E. Protein kinase A causes dephosphorylation of glycogen synthase, which changes its conformation and activity

Answer: E. Protein kinase A causes dephosphorylation of glycogen synthase, which changes its conformation and activity. Chapter 36, Objective 13: Glycogen is not made in the liver during fasting. Why not?

When sedentary fasting person begins to exercise, all of the follow occur EXCEPT A. Exercise activates AMP-protein kinase and results in more glut4 moving to the cell membrane B. AMP and epinephrine both activate phosphorylase so that glycogenolysis occurs C. AMP and epinephrine both cause activation of phosphofructokinase-1 in muscle D. AMP-protein kinase inhibits malonyl CoA production and activates carnitine: palmitoyltransferase-1 E. Since more ATP is made from fatty acids and muscle glycogen, less blood glucose is used

Answer: E. Since more ATP is made from fatty acids and muscle glycogen, less blood glucose is used. Chapter 36, Objective 19: What is the effect of exercise upon the use of blood glucose by muscle in the fasting state? What is the mechanism?

When more carbohydrate is consumed than can be used for present energy needs and glycogen storage, the carbohydrate is converted to fatty acid in the liver. All of the following statements about the first part of this pathway are true EXCEPT A. Carbohydrate is converted to pyruvate using glycolysis B. Activated by dephosphorylation of phosphofructokinase-2/fructose-2,6-bisphosphatase C. The allosteric activator fructose-2,6-bisphosphate is required D. The dephosphorylation of pyruvate kinase is required E. The inhibition of protein phosphatases by insulin is required

Answer: E. The inhibition of protein phosphatases by insulin is required. Chapter 36, Objective 2: What pathway provides for the production of pyruvate to be used for fatty acid synthesis in the fed state? How is this pathway regulated?

All of the following help to explain why ketone bodies are produced during a fast EXCEPT A. Low insulin to glucagon ratio ensures the activation of hormone sensitive lipase and mobilization of fatty acids B. Low insulin to glucagon ratio ensures the entrance of activated fatty acids into the mitochondria C. If more acetyl CoA is made than is needed by the TCA cycle, then hydroxymethylglutaryl CoA will be made D. The liver has an active enzyme, hydroxymethylglutaryl CoA lyase that produces acetoacetate and acetyl CoA E. The liver has an active enzyme beta-hydroxybutyrate dehydrogenase that converts acetoacetate into acetone

Answer: E. The liver has an active enzyme beta-hydroxybutyrate dehydrogenase that converts acetoacetate into acetone. Chapter 36, Objective 16: Why are ketone bodies produced during a fast?

Concerning ALT, AST and all other transamination reactions, all of the following are true EXCEPT A. The cofactor may be called pyridoxal phosphate (PLP) B. The cofactor is derived from pyridoxine or vitamin B6 C. Pyridoxal phosphate is called a prosthetic group because it is held tightly to enzymes D. Pyridoxamine is an intermediate in the reaction E. These enzymes are classified as oxidoreductases

Answer: E. These enzymes are classified as oxidoreductases. Chapter 38, Objective 5: What are the cofactors for ALT and AST. Are the coenzymes prosthetic groups? What vitamin are the cofactors derived from?