Datasets:

MedRAG
/

textbooks

Dataset card Data Studio Files Files and versions Community

Split (1)

train · 126k rows

Subsets and Splits

No community queries yet

The top public SQL queries from the community will appear here once available.

id stringlengths 14 28	title stringclasses 18 values	content stringlengths 2 999	contents stringlengths 19 1.02k
Biochemistry_Lippincott_1883	Biochemistry_Lippinco	resulting in an increase in TAG that gets sent out of the liver as components of very-low-density lipoproteins (VLDL). [Note: The hypoglycemia results in release of epinephrine and the activation of TAG lipolysis with release of free FA into the blood. The FA are oxidized, with the excess used in hepatic TAG synthesis.] The acetyl CoA is also a substrate for cholesterol synthesis. Thus, the increase in glycolysis results in the hyperlipidemia seen in JS (see figure below).	Biochemistry_Lippinco. resulting in an increase in TAG that gets sent out of the liver as components of very-low-density lipoproteins (VLDL). [Note: The hypoglycemia results in release of epinephrine and the activation of TAG lipolysis with release of free FA into the blood. The FA are oxidized, with the excess used in hepatic TAG synthesis.] The acetyl CoA is also a substrate for cholesterol synthesis. Thus, the increase in glycolysis results in the hyperlipidemia seen in JS (see figure below).
Biochemistry_Lippincott_1884	Biochemistry_Lippinco	Case 3: Answers to Review Questions RQ1.Correct answer = A. Diabetes is characterized by hyperglycemia. Chronic hyperglycemia can result in the nonenzymatic glycosylation (glycation) of hemoglobin (Hb), producing HbA1c. Therefore, measurement of glucose or	Biochemistry_Lippinco. Case 3: Answers to Review Questions RQ1.Correct answer = A. Diabetes is characterized by hyperglycemia. Chronic hyperglycemia can result in the nonenzymatic glycosylation (glycation) of hemoglobin (Hb), producing HbA1c. Therefore, measurement of glucose or
Biochemistry_Lippincott_1885	Biochemistry_Lippinco	HbA1c in the blood is used to diagnose diabetes. In response to physiologic stress (for example, a urinary tract infection), secretion of counterregulatory hormones (such as the catecholamines) results in a rise in blood glucose. Glucose is a reducing sugar. It is type 2 diabetes (T2D) that is associated with obesity and a sedentary lifestyle and is caused by insensitivity to insulin (insulin resistance). T1D is caused by lack of insulin as a result of the autoimmune destruction of pancreatic β cells. Even individuals on a program of tight glycemic control do not achieve euglycemia. RQ2.Correct answer = E. The ketone bodies 3-hydroxybutyrate and acetoacetate are organic acids, and their ionization contributes to the proton load of the body. Ketone bodies are made in the mitochondria of liver cells using acetyl coenzyme A (CoA) generated primarily from the β-oxidation of fatty acids ([FA]; see figure on the next page). Because they are water soluble, they do not require a transporter.	Biochemistry_Lippinco. HbA1c in the blood is used to diagnose diabetes. In response to physiologic stress (for example, a urinary tract infection), secretion of counterregulatory hormones (such as the catecholamines) results in a rise in blood glucose. Glucose is a reducing sugar. It is type 2 diabetes (T2D) that is associated with obesity and a sedentary lifestyle and is caused by insensitivity to insulin (insulin resistance). T1D is caused by lack of insulin as a result of the autoimmune destruction of pancreatic β cells. Even individuals on a program of tight glycemic control do not achieve euglycemia. RQ2.Correct answer = E. The ketone bodies 3-hydroxybutyrate and acetoacetate are organic acids, and their ionization contributes to the proton load of the body. Ketone bodies are made in the mitochondria of liver cells using acetyl coenzyme A (CoA) generated primarily from the β-oxidation of fatty acids ([FA]; see figure on the next page). Because they are water soluble, they do not require a transporter.
Biochemistry_Lippincott_1886	Biochemistry_Lippinco	cells using acetyl coenzyme A (CoA) generated primarily from the β-oxidation of fatty acids ([FA]; see figure on the next page). Because they are water soluble, they do not require a transporter. The liver cannot use them because it lacks the enzyme thiophorase, which moves CoA from succinyl CoA to acetoacetate for conversion to two molecules of acetyl CoA. It is the acetone released in the breath that can impart a fruity odor.	Biochemistry_Lippinco. cells using acetyl coenzyme A (CoA) generated primarily from the β-oxidation of fatty acids ([FA]; see figure on the next page). Because they are water soluble, they do not require a transporter. The liver cannot use them because it lacks the enzyme thiophorase, which moves CoA from succinyl CoA to acetoacetate for conversion to two molecules of acetyl CoA. It is the acetone released in the breath that can impart a fruity odor.
Biochemistry_Lippincott_1887	Biochemistry_Lippinco	RQ3.Correct answer = A. Malonyl CoA, an intermediate of FA synthesis, inhibits FA β-oxidation through inhibition of carnitine palmitoyltransferase I. Lipolysis occurs when the insulin/counterregulatory hormone ratio decreases. Acetyl CoA, the product of FA β-oxidation, inhibits the pyruvate dehydrogenase (PDH) complex through activation of PDH kinase and activates pyruvate carboxylase. Acetyl CoA, then, pushes pyruvate to gluconeogenesis. β-Oxidation generates reduced nicotinamide adenine dinucleotide (NADH), the reducing equivalent required for gluconeogenesis. FA are not readily catabolized for energy by the brain. Case 3: Answers to Thought Questions	Biochemistry_Lippinco. RQ3.Correct answer = A. Malonyl CoA, an intermediate of FA synthesis, inhibits FA β-oxidation through inhibition of carnitine palmitoyltransferase I. Lipolysis occurs when the insulin/counterregulatory hormone ratio decreases. Acetyl CoA, the product of FA β-oxidation, inhibits the pyruvate dehydrogenase (PDH) complex through activation of PDH kinase and activates pyruvate carboxylase. Acetyl CoA, then, pushes pyruvate to gluconeogenesis. β-Oxidation generates reduced nicotinamide adenine dinucleotide (NADH), the reducing equivalent required for gluconeogenesis. FA are not readily catabolized for energy by the brain. Case 3: Answers to Thought Questions
Biochemistry_Lippincott_1888	Biochemistry_Lippinco	Case 3: Answers to Thought Questions TQ1.Hypoinsulinemia results in hyperglycemia because insulin is required for the uptake of blood glucose by muscle and adipose tissue. Their glucose transporter (GLUT-4) is insulin dependent in that insulin is required for movement of the transporter to the cell surface from intracellular storage sites. Insulin is also required to suppress hepatic gluconeogenesis. Insulin suppresses the release of glucagon from pancreatic α cells. The resulting rise in the insulin/glucagon ratio results in the dephosphorylation and activation of the kinase domain of bifunctional phosphofructokinase-2 (PFK-2). The fructose 2,6bisphosphate produced by PFK-2 activates phosphofructokinase-1 of glycolysis (see figure below). It also inhibits fructose 1,6-bisphosphatase (FBP-2), thereby inhibiting gluconeogenesis. With hypoinsulinemia, the failure to take up glucose from the blood while simultaneously sending it out into the blood results in hyperglycemia.	Biochemistry_Lippinco. Case 3: Answers to Thought Questions TQ1.Hypoinsulinemia results in hyperglycemia because insulin is required for the uptake of blood glucose by muscle and adipose tissue. Their glucose transporter (GLUT-4) is insulin dependent in that insulin is required for movement of the transporter to the cell surface from intracellular storage sites. Insulin is also required to suppress hepatic gluconeogenesis. Insulin suppresses the release of glucagon from pancreatic α cells. The resulting rise in the insulin/glucagon ratio results in the dephosphorylation and activation of the kinase domain of bifunctional phosphofructokinase-2 (PFK-2). The fructose 2,6bisphosphate produced by PFK-2 activates phosphofructokinase-1 of glycolysis (see figure below). It also inhibits fructose 1,6-bisphosphatase (FBP-2), thereby inhibiting gluconeogenesis. With hypoinsulinemia, the failure to take up glucose from the blood while simultaneously sending it out into the blood results in hyperglycemia.
Biochemistry_Lippincott_1889	Biochemistry_Lippinco	TQ2.The blood glucose level has exceeded the capacity of the kidney to reabsorb glucose (via a sodium-dependent glucose transporter [SGLT]). The high concentration of glucose in the urine osmotically draws water from the body. This causes increased urination (polyuria) with loss of water that results in dehydration. TQ3.The NADH generated in FA β-oxidation inhibits the tricarboxylic acid (TCA) cycle at the three NADH-producing dehydrogenase steps. This shifts acetyl CoA away from oxidation in the TCA cycle and toward use as a substrate in hepatic ketogenesis.	Biochemistry_Lippinco. TQ2.The blood glucose level has exceeded the capacity of the kidney to reabsorb glucose (via a sodium-dependent glucose transporter [SGLT]). The high concentration of glucose in the urine osmotically draws water from the body. This causes increased urination (polyuria) with loss of water that results in dehydration. TQ3.The NADH generated in FA β-oxidation inhibits the tricarboxylic acid (TCA) cycle at the three NADH-producing dehydrogenase steps. This shifts acetyl CoA away from oxidation in the TCA cycle and toward use as a substrate in hepatic ketogenesis.
Biochemistry_Lippincott_1890	Biochemistry_Lippinco	TQ4.MW was in negative nitrogen balance: More nitrogen was going out than coming in. This is reflected in the elevated blood urea nitrogen (BUN) level seen in the patient (see figure at top right). [Note: The BUN value also reflects dehydration.] Muscle proteolysis and amino acid catabolism are occurring as a result of the fall in insulin. (Recall that skeletal muscle does not express the glucagon receptor.) Amino acid catabolism produces ammonia (NH3), which is converted to urea by the hepatic urea cycle and sent into the blood. [Note: Urea in the urine is reported as urinary urea nitrogen.] TQ5.The Kussmaul respiration seen in MW is a respiratory response to the metabolic acidosis. Hyperventilation blows off CO2 and water, reducing the concentration of protons (H+) and bicarbonate (HCO3−) as reflected in the following equation: The renal response includes, in part, the excretion of H+ as ammonium (NH4+). Degradation of branched-chain amino acids in skeletal muscle results in the	Biochemistry_Lippinco. TQ4.MW was in negative nitrogen balance: More nitrogen was going out than coming in. This is reflected in the elevated blood urea nitrogen (BUN) level seen in the patient (see figure at top right). [Note: The BUN value also reflects dehydration.] Muscle proteolysis and amino acid catabolism are occurring as a result of the fall in insulin. (Recall that skeletal muscle does not express the glucagon receptor.) Amino acid catabolism produces ammonia (NH3), which is converted to urea by the hepatic urea cycle and sent into the blood. [Note: Urea in the urine is reported as urinary urea nitrogen.] TQ5.The Kussmaul respiration seen in MW is a respiratory response to the metabolic acidosis. Hyperventilation blows off CO2 and water, reducing the concentration of protons (H+) and bicarbonate (HCO3−) as reflected in the following equation: The renal response includes, in part, the excretion of H+ as ammonium (NH4+). Degradation of branched-chain amino acids in skeletal muscle results in the
Biochemistry_Lippincott_1891	Biochemistry_Lippinco	as reflected in the following equation: The renal response includes, in part, the excretion of H+ as ammonium (NH4+). Degradation of branched-chain amino acids in skeletal muscle results in the release of large amounts of glutamine (Gln) into the blood. The kidneys take up and catabolize the Gln, generating NH3 in the process. The NH3 is converted to NH4+ by secreted H+ and is excreted (see figure at middle right). [Note: When ketone bodies are plentiful, enterocytes shift to using them as a fuel instead of	Biochemistry_Lippinco. as reflected in the following equation: The renal response includes, in part, the excretion of H+ as ammonium (NH4+). Degradation of branched-chain amino acids in skeletal muscle results in the release of large amounts of glutamine (Gln) into the blood. The kidneys take up and catabolize the Gln, generating NH3 in the process. The NH3 is converted to NH4+ by secreted H+ and is excreted (see figure at middle right). [Note: When ketone bodies are plentiful, enterocytes shift to using them as a fuel instead of
Biochemistry_Lippincott_1892	Biochemistry_Lippinco	Gln. This increases the amount of Gln going to the kidney.] TQ6.Because FA β-oxidation supplies the acetyl CoA substrate for ketogenesis, impaired β-oxidation decreases the ability to make ketone bodies. Ketone bodies are an alternate to the use of glucose, and, thus, dependence on glucose increases. Because FA β-oxidation supplies the NADH and the nucleoside triphosphates needed for gluconeogenesis, glucose production decreases. The result is a hypoketotic hypoglycemia. Recall that this was seen with medium-chain acyl CoA dehydrogenase (MCAD) deficiency. Case 4: Answers to Review Questions	Biochemistry_Lippinco. Gln. This increases the amount of Gln going to the kidney.] TQ6.Because FA β-oxidation supplies the acetyl CoA substrate for ketogenesis, impaired β-oxidation decreases the ability to make ketone bodies. Ketone bodies are an alternate to the use of glucose, and, thus, dependence on glucose increases. Because FA β-oxidation supplies the NADH and the nucleoside triphosphates needed for gluconeogenesis, glucose production decreases. The result is a hypoketotic hypoglycemia. Recall that this was seen with medium-chain acyl CoA dehydrogenase (MCAD) deficiency. Case 4: Answers to Review Questions
Biochemistry_Lippincott_1893	Biochemistry_Lippinco	RQ1.Answer = D. The rise in reduced nicotinamide adenine dinucleotide (NADH) in the mitochondria decreases the tricarboxylic acid (TCA) cycle, fatty acid (FA) oxidation, and gluconeogenesis. NADH inhibits the isocitrate dehydrogenase reaction, the key regulated step of the TCA cycle, and the αketoglutarate dehydrogenase reaction (see figure at bottom right). It also favors the reduction of oxaloacetate (OAA) to malate (not malate to OAA), decreasing the availability of OAA for condensation with acetyl coenzyme A (CoA) in the TCA cycle and for gluconeogenesis. FA oxidation requires the oxidized form of nicotinamide adenine dinucleotide (NAD+) for the 3-hydroxyacyl CoA dehydrogenase step and, thus, is inhibited by the rise in NADH. The decrease in FA oxidation decreases the production of ATP and acetyl CoA (the allosteric activator of pyruvate carboxylase) needed for gluconeogenesis. Lipolysis is activated in fasting as a consequence of the fall in insulin and the rise in catecholamines	Biochemistry_Lippinco. RQ1.Answer = D. The rise in reduced nicotinamide adenine dinucleotide (NADH) in the mitochondria decreases the tricarboxylic acid (TCA) cycle, fatty acid (FA) oxidation, and gluconeogenesis. NADH inhibits the isocitrate dehydrogenase reaction, the key regulated step of the TCA cycle, and the αketoglutarate dehydrogenase reaction (see figure at bottom right). It also favors the reduction of oxaloacetate (OAA) to malate (not malate to OAA), decreasing the availability of OAA for condensation with acetyl coenzyme A (CoA) in the TCA cycle and for gluconeogenesis. FA oxidation requires the oxidized form of nicotinamide adenine dinucleotide (NAD+) for the 3-hydroxyacyl CoA dehydrogenase step and, thus, is inhibited by the rise in NADH. The decrease in FA oxidation decreases the production of ATP and acetyl CoA (the allosteric activator of pyruvate carboxylase) needed for gluconeogenesis. Lipolysis is activated in fasting as a consequence of the fall in insulin and the rise in catecholamines
Biochemistry_Lippincott_1894	Biochemistry_Lippinco	and acetyl CoA (the allosteric activator of pyruvate carboxylase) needed for gluconeogenesis. Lipolysis is activated in fasting as a consequence of the fall in insulin and the rise in catecholamines that result in activation of hormone-sensitive lipase.	Biochemistry_Lippinco. and acetyl CoA (the allosteric activator of pyruvate carboxylase) needed for gluconeogenesis. Lipolysis is activated in fasting as a consequence of the fall in insulin and the rise in catecholamines that result in activation of hormone-sensitive lipase.
Biochemistry_Lippincott_1895	Biochemistry_Lippinco	RQ2.Answer = E. The irreversible, oxidative portion of the pentose phosphate pathway provides the nicotinamide adenine dinucleotide phosphate (NADPH) that supplies the reducing equivalents needed for activity of cytochrome P450 (CYP) proteins and for the regeneration of functional (reduced) glutathione. It is also an important source of NADPH for reductive biosynthetic processes in the cytosol, such as FA and cholesterol synthesis. [Note: Malic enzyme is another source.] CYP proteins are monooxygenases (mixed-function oxidases). They incorporate one O atom from O2 into the substrate as the other is reduced to water. It is the CYP proteins of the smooth endoplasmic reticular membrane that are involved in detoxification reactions. Those of the inner mitochondrial membrane are involved in the synthesis of steroid hormones, bile acids, and vitamin D. Reactive oxygen species are reduced by glutathione peroxidase as glutathione is oxidized. RQ3.Answer = C. Serotonin is released by activated	Biochemistry_Lippinco. RQ2.Answer = E. The irreversible, oxidative portion of the pentose phosphate pathway provides the nicotinamide adenine dinucleotide phosphate (NADPH) that supplies the reducing equivalents needed for activity of cytochrome P450 (CYP) proteins and for the regeneration of functional (reduced) glutathione. It is also an important source of NADPH for reductive biosynthetic processes in the cytosol, such as FA and cholesterol synthesis. [Note: Malic enzyme is another source.] CYP proteins are monooxygenases (mixed-function oxidases). They incorporate one O atom from O2 into the substrate as the other is reduced to water. It is the CYP proteins of the smooth endoplasmic reticular membrane that are involved in detoxification reactions. Those of the inner mitochondrial membrane are involved in the synthesis of steroid hormones, bile acids, and vitamin D. Reactive oxygen species are reduced by glutathione peroxidase as glutathione is oxidized. RQ3.Answer = C. Serotonin is released by activated
Biochemistry_Lippincott_1896	Biochemistry_Lippinco	synthesis of steroid hormones, bile acids, and vitamin D. Reactive oxygen species are reduced by glutathione peroxidase as glutathione is oxidized. RQ3.Answer = C. Serotonin is released by activated platelets and causes vasoconstriction and platelet aggregation. [Note: Platelets do not synthesize serotonin, but they take up that which was made in the intestine and secreted into the blood.] Serotonin is associated with a feeling of well-being. It is degraded to 5-hydroxyindoleacetic acid by monoamine oxidase that catalyzes oxidative deamination. It is catechol-O-methyltransferase that catalyzes the methylation step in the degradation of the catecholamines. Serotonin is synthesized from tryptophan in a two-step process that utilizes tetrahydrobiopterin (BH4) requiring tryptophan hydroxylase and a pyridoxal phosphate (PLP)-requiring decarboxylase (see figure at right). RQ4.Answer = B. The exocrine pancreas secretes enzymes required for the digestion of dietary carbohydrate, protein, and	Biochemistry_Lippinco. synthesis of steroid hormones, bile acids, and vitamin D. Reactive oxygen species are reduced by glutathione peroxidase as glutathione is oxidized. RQ3.Answer = C. Serotonin is released by activated platelets and causes vasoconstriction and platelet aggregation. [Note: Platelets do not synthesize serotonin, but they take up that which was made in the intestine and secreted into the blood.] Serotonin is associated with a feeling of well-being. It is degraded to 5-hydroxyindoleacetic acid by monoamine oxidase that catalyzes oxidative deamination. It is catechol-O-methyltransferase that catalyzes the methylation step in the degradation of the catecholamines. Serotonin is synthesized from tryptophan in a two-step process that utilizes tetrahydrobiopterin (BH4) requiring tryptophan hydroxylase and a pyridoxal phosphate (PLP)-requiring decarboxylase (see figure at right). RQ4.Answer = B. The exocrine pancreas secretes enzymes required for the digestion of dietary carbohydrate, protein, and
Biochemistry_Lippincott_1897	Biochemistry_Lippinco	and a pyridoxal phosphate (PLP)-requiring decarboxylase (see figure at right). RQ4.Answer = B. The exocrine pancreas secretes enzymes required for the digestion of dietary carbohydrate, protein, and fat. The endocrine pancreas secretes the peptide hormones insulin and glucagon. Damage that affects the functions of the pancreas would lead to diabetes (decreased insulin) and steatorrhea (fatty stool), with the latter the consequence of maldigestion of dietary fat. As was seen with the rise of troponins in a myocardial infarction and transaminases in liver damage, loss of cellular integrity (as would be seen in autodigestion of the pancreas) results in proteins that normally are intracellular being found in higher-than-normal concentrations in the blood. Secretin causes the pancreas to release bicarbonate to raise the pH of the chyme coming to the intestine from the stomach. Pancreatic enzymes work best at neutral or slightly alkaline pH. Pancreatitis is seen in individuals with	Biochemistry_Lippinco. and a pyridoxal phosphate (PLP)-requiring decarboxylase (see figure at right). RQ4.Answer = B. The exocrine pancreas secretes enzymes required for the digestion of dietary carbohydrate, protein, and fat. The endocrine pancreas secretes the peptide hormones insulin and glucagon. Damage that affects the functions of the pancreas would lead to diabetes (decreased insulin) and steatorrhea (fatty stool), with the latter the consequence of maldigestion of dietary fat. As was seen with the rise of troponins in a myocardial infarction and transaminases in liver damage, loss of cellular integrity (as would be seen in autodigestion of the pancreas) results in proteins that normally are intracellular being found in higher-than-normal concentrations in the blood. Secretin causes the pancreas to release bicarbonate to raise the pH of the chyme coming to the intestine from the stomach. Pancreatic enzymes work best at neutral or slightly alkaline pH. Pancreatitis is seen in individuals with
Biochemistry_Lippincott_1898	Biochemistry_Lippinco	to release bicarbonate to raise the pH of the chyme coming to the intestine from the stomach. Pancreatic enzymes work best at neutral or slightly alkaline pH. Pancreatitis is seen in individuals with hypertriglyceridemia as a result of a deficiency in lipoprotein lipase or its coenzyme, apolipoprotein C-II.	Biochemistry_Lippinco. to release bicarbonate to raise the pH of the chyme coming to the intestine from the stomach. Pancreatic enzymes work best at neutral or slightly alkaline pH. Pancreatitis is seen in individuals with hypertriglyceridemia as a result of a deficiency in lipoprotein lipase or its coenzyme, apolipoprotein C-II.
Biochemistry_Lippincott_1899	Biochemistry_Lippinco	Case 4: Answers to Thought Questions TQ1.A. The rise in cytosolic NADH seen with ethanol metabolism inhibits glycolysis. The glyceraldehyde 3-phosphate dehydrogenase step requires NAD+, which gets reduced as glyceraldehyde 3-phosphate gets oxidized. With the rise in NADH, glyceraldehyde 3-phosphate accumulates.	Biochemistry_Lippinco. Case 4: Answers to Thought Questions TQ1.A. The rise in cytosolic NADH seen with ethanol metabolism inhibits glycolysis. The glyceraldehyde 3-phosphate dehydrogenase step requires NAD+, which gets reduced as glyceraldehyde 3-phosphate gets oxidized. With the rise in NADH, glyceraldehyde 3-phosphate accumulates.
Biochemistry_Lippincott_1900	Biochemistry_Lippinco	B. Glyceraldehyde 3-phosphate from glycolysis is converted to glycerol 3phosphate, the initial acceptor of FA in triacylglycerol (TAG) synthesis (see figure at right). FA are available because of increased synthesis (from acetyl CoA, which is increased as a result of both increased production from the acetate product of acetaldehyde oxidation and decreased use in the TCA cycle), increased availability from lipolysis in adipose tissue, and decreased degradation. The TAG produced in the liver accumulate (due, in part, to decreased production of very-low-density lipoproteins) and cause fatty liver (steatosis). Hepatic steatosis is an early (and reversible) stage in alcohol-related liver disease. Subsequent stages are alcohol-related hepatitis (sometimes reversible) and cirrhosis (irreversible).	Biochemistry_Lippinco. B. Glyceraldehyde 3-phosphate from glycolysis is converted to glycerol 3phosphate, the initial acceptor of FA in triacylglycerol (TAG) synthesis (see figure at right). FA are available because of increased synthesis (from acetyl CoA, which is increased as a result of both increased production from the acetate product of acetaldehyde oxidation and decreased use in the TCA cycle), increased availability from lipolysis in adipose tissue, and decreased degradation. The TAG produced in the liver accumulate (due, in part, to decreased production of very-low-density lipoproteins) and cause fatty liver (steatosis). Hepatic steatosis is an early (and reversible) stage in alcohol-related liver disease. Subsequent stages are alcohol-related hepatitis (sometimes reversible) and cirrhosis (irreversible).
Biochemistry_Lippincott_1901	Biochemistry_Lippinco	TQ2.The rise in NADH favors the reduction of pyruvate to lactate by lactate dehydrogenase. Lactate decreases the renal excretion of uric acid, thereby causing hyperuricemia, a necessary step in an acute gouty attack. [Note: The shift from pyruvate to lactate decreases the availability of pyruvate, a substrate for gluconeogenesis. This contributes to the hypoglycemia seen in AK.] TQ3.Prothrombin time (PT) measures the time it takes for plasma to clot after the addition of tissue factor (FIII), thereby allowing evaluation of the extrinsic (and common) pathways of coagulation. In the extrinsic pathway, FIII activates FVII in a calcium (Ca2+)-and phospholipid (PL)-dependent process (see figure at bottom right). FVII, like most of the proteins of clotting, is made by the liver. Alcohol-induced liver damage can decrease its synthesis. Additionally, FVII has a short half-life, and, as a γ-carboxyglutamate (Gla)-containing protein, its synthesis requires vitamin K. Poor nutrition can result	Biochemistry_Lippinco. TQ2.The rise in NADH favors the reduction of pyruvate to lactate by lactate dehydrogenase. Lactate decreases the renal excretion of uric acid, thereby causing hyperuricemia, a necessary step in an acute gouty attack. [Note: The shift from pyruvate to lactate decreases the availability of pyruvate, a substrate for gluconeogenesis. This contributes to the hypoglycemia seen in AK.] TQ3.Prothrombin time (PT) measures the time it takes for plasma to clot after the addition of tissue factor (FIII), thereby allowing evaluation of the extrinsic (and common) pathways of coagulation. In the extrinsic pathway, FIII activates FVII in a calcium (Ca2+)-and phospholipid (PL)-dependent process (see figure at bottom right). FVII, like most of the proteins of clotting, is made by the liver. Alcohol-induced liver damage can decrease its synthesis. Additionally, FVII has a short half-life, and, as a γ-carboxyglutamate (Gla)-containing protein, its synthesis requires vitamin K. Poor nutrition can result
Biochemistry_Lippincott_1902	Biochemistry_Lippinco	liver damage can decrease its synthesis. Additionally, FVII has a short half-life, and, as a γ-carboxyglutamate (Gla)-containing protein, its synthesis requires vitamin K. Poor nutrition can result in decreased availability of vitamin K and, therefore, decreased ability to clot. [Note: Severe liver disease results in prolonged PT and activated partial thromboplastin time, or aPPt.]	Biochemistry_Lippinco. liver damage can decrease its synthesis. Additionally, FVII has a short half-life, and, as a γ-carboxyglutamate (Gla)-containing protein, its synthesis requires vitamin K. Poor nutrition can result in decreased availability of vitamin K and, therefore, decreased ability to clot. [Note: Severe liver disease results in prolonged PT and activated partial thromboplastin time, or aPPt.]
Biochemistry_Lippincott_1903	Biochemistry_Lippinco	TQ4.Administration of folate can mask a deficiency in vitamin B12 by reversing the hematologic manifestation (macrocytic anemia) of the deficiency. However, folate has no effect on the neurologic damage caused by B12 deficiency. Over time, then, the neurologic effects can become severe and irreversible. Thus, folate can mask a deficiency of B12 and prevent treatment until the neuropathy is apparent. III. Focused Cases Case 1: Microcytic Anemia Patient Presentation: ME is a 24-year-old man who is being evaluated as a follow-up to a preplacement medical evaluation he had prior to starting his new job. Focused History: ME has no significant medical issues. His family history is unremarkable, but he knows little of the health status of those family members who remain in Greece. Pertinent Findings: The physical examination was normal. Routine analysis of his blood included the following results:	Biochemistry_Lippinco. TQ4.Administration of folate can mask a deficiency in vitamin B12 by reversing the hematologic manifestation (macrocytic anemia) of the deficiency. However, folate has no effect on the neurologic damage caused by B12 deficiency. Over time, then, the neurologic effects can become severe and irreversible. Thus, folate can mask a deficiency of B12 and prevent treatment until the neuropathy is apparent. III. Focused Cases Case 1: Microcytic Anemia Patient Presentation: ME is a 24-year-old man who is being evaluated as a follow-up to a preplacement medical evaluation he had prior to starting his new job. Focused History: ME has no significant medical issues. His family history is unremarkable, but he knows little of the health status of those family members who remain in Greece. Pertinent Findings: The physical examination was normal. Routine analysis of his blood included the following results:
Biochemistry_Lippincott_1904	Biochemistry_Lippinco	Pertinent Findings: The physical examination was normal. Routine analysis of his blood included the following results: Based on the data, hemoglobin (Hb) electrophoresis was performed. The results are as follows: H = High; L = Low. [Note: HbA includes HbA1c.] Diagnosis: ME has β-thalassemia trait (β-thalassemia minor) that is causing a microcytic anemia (see image at right). Ethnicity (such as being of Mediterranean origin) influences the risk for thalassemia. Treatment: None is required at this time. Patients are advised that iron supplements will not prevent their anemia. Prognosis: β-Thalassemia trait does not cause mortality or significant morbidity. Patients should be informed of the genetic nature of their autosomal-recessive condition for family planning considerations because homozygous β-thalassemia (Cooley anemia) is a serious disorder. Case-Related Questions: Choose the ONE best answer.	Biochemistry_Lippinco. Pertinent Findings: The physical examination was normal. Routine analysis of his blood included the following results: Based on the data, hemoglobin (Hb) electrophoresis was performed. The results are as follows: H = High; L = Low. [Note: HbA includes HbA1c.] Diagnosis: ME has β-thalassemia trait (β-thalassemia minor) that is causing a microcytic anemia (see image at right). Ethnicity (such as being of Mediterranean origin) influences the risk for thalassemia. Treatment: None is required at this time. Patients are advised that iron supplements will not prevent their anemia. Prognosis: β-Thalassemia trait does not cause mortality or significant morbidity. Patients should be informed of the genetic nature of their autosomal-recessive condition for family planning considerations because homozygous β-thalassemia (Cooley anemia) is a serious disorder. Case-Related Questions: Choose the ONE best answer.
Biochemistry_Lippincott_1905	Biochemistry_Lippinco	Case-Related Questions: Choose the ONE best answer. Q1. Mutations to the gene for β globin that result in decreased production of the protein are the cause of β-thalassemia. The mutations primarily affect gene transcription or posttranscriptional processing of the messenger RNA (mRNA) product. Which of the following statements concerning mRNA is correct? A. Eukaryotic mRNA is polycistronic. B. mRNA synthesis involves trans-acting factors binding to cis-acting elements. C. mRNA synthesis is terminated at the DNA base sequence thymine adenine guanine (TAG). D. Polyadenylation of the 5′-end of eukaryotic mRNA requires a methyl donor.	Biochemistry_Lippinco. Case-Related Questions: Choose the ONE best answer. Q1. Mutations to the gene for β globin that result in decreased production of the protein are the cause of β-thalassemia. The mutations primarily affect gene transcription or posttranscriptional processing of the messenger RNA (mRNA) product. Which of the following statements concerning mRNA is correct? A. Eukaryotic mRNA is polycistronic. B. mRNA synthesis involves trans-acting factors binding to cis-acting elements. C. mRNA synthesis is terminated at the DNA base sequence thymine adenine guanine (TAG). D. Polyadenylation of the 5′-end of eukaryotic mRNA requires a methyl donor.
Biochemistry_Lippincott_1906	Biochemistry_Lippinco	C. mRNA synthesis is terminated at the DNA base sequence thymine adenine guanine (TAG). D. Polyadenylation of the 5′-end of eukaryotic mRNA requires a methyl donor. E. Splicing of eukaryotic mRNA involves removal of exons and joining of introns by the proteasome. Q2. HbA, a tetramer of 2 α and 2 β globin chains, delivers O2 from the lungs to the tissues and protons and CO2 from the tissues to the lungs. Increased concentration of which of the following will result in decreased O2 delivery by HbA? A. 2,3-Bisphosphoglycerate B. Carbon dioxide C. Carbon monoxide D. Protons Q3. What is the basis for the increase in HbA2 and HbF (fetal Hb) in the βthalassemias? Q4. Why is the allele-specific oligonucleotide (ASO) hybridization technique useful in the diagnosis of all cases of sickle cell anemia but not all cases of β-thalassemia? Case 2: Skin Rash Patient Presentation: KL is a 34-year-old woman who presents with a red, nonitchy rash on her left thigh and flu-like symptoms.	Biochemistry_Lippinco. C. mRNA synthesis is terminated at the DNA base sequence thymine adenine guanine (TAG). D. Polyadenylation of the 5′-end of eukaryotic mRNA requires a methyl donor. E. Splicing of eukaryotic mRNA involves removal of exons and joining of introns by the proteasome. Q2. HbA, a tetramer of 2 α and 2 β globin chains, delivers O2 from the lungs to the tissues and protons and CO2 from the tissues to the lungs. Increased concentration of which of the following will result in decreased O2 delivery by HbA? A. 2,3-Bisphosphoglycerate B. Carbon dioxide C. Carbon monoxide D. Protons Q3. What is the basis for the increase in HbA2 and HbF (fetal Hb) in the βthalassemias? Q4. Why is the allele-specific oligonucleotide (ASO) hybridization technique useful in the diagnosis of all cases of sickle cell anemia but not all cases of β-thalassemia? Case 2: Skin Rash Patient Presentation: KL is a 34-year-old woman who presents with a red, nonitchy rash on her left thigh and flu-like symptoms.
Biochemistry_Lippincott_1907	Biochemistry_Lippinco	Case 2: Skin Rash Patient Presentation: KL is a 34-year-old woman who presents with a red, nonitchy rash on her left thigh and flu-like symptoms. Focused History: KL reports that the rash first appeared a little over 2 weeks ago. It started out small but has gotten larger. She also thinks she is getting the flu because her muscles and joints ache (myalgia and arthralgia, respectively), and she has had a headache for the last few days. Upon questioning, KL reports that she and her husband took a camping trip through New England last month. Pertinent Findings: The physical examination is remarkable for the presence of a red, circular, flat lesion ~11 cm in size that resembles a bullseye (erythema migrans) (see image at right). KL also has a low-grade fever. Diagnosis: KL has Lyme disease caused by the bacterium Borrelia burgdorferi, which is transmitted by the bite of a tick in the genus Ixodes. Infected ticks are endemic in the Northeast region of the United States.	Biochemistry_Lippinco. Case 2: Skin Rash Patient Presentation: KL is a 34-year-old woman who presents with a red, nonitchy rash on her left thigh and flu-like symptoms. Focused History: KL reports that the rash first appeared a little over 2 weeks ago. It started out small but has gotten larger. She also thinks she is getting the flu because her muscles and joints ache (myalgia and arthralgia, respectively), and she has had a headache for the last few days. Upon questioning, KL reports that she and her husband took a camping trip through New England last month. Pertinent Findings: The physical examination is remarkable for the presence of a red, circular, flat lesion ~11 cm in size that resembles a bullseye (erythema migrans) (see image at right). KL also has a low-grade fever. Diagnosis: KL has Lyme disease caused by the bacterium Borrelia burgdorferi, which is transmitted by the bite of a tick in the genus Ixodes. Infected ticks are endemic in the Northeast region of the United States.
Biochemistry_Lippincott_1908	Biochemistry_Lippinco	Treatment: KL is prescribed doxycycline, an antibiotic in the tetracycline family. Monitoring of KL will continue until all symptoms have completely resolved. Blood is drawn for clinical laboratory tests. Prognosis: Patients treated with the appropriate antibiotic in the early stages of Lyme disease typically recover quickly and completely. Case-Related Questions: Choose the ONE best answer. Q1. Antibiotics in the tetracycline class inhibit protein synthesis (translation) at the initiation step. Which of the following statements about translation is correct? A. In eukaryotic translation, the initiating amino acid is formylated methionine. B. Only the charged initiating transfer RNA goes directly to the ribosomal A site. C. Peptidyltransferase is a ribozyme that forms the peptide bond between two amino acids. D. Prokaryotic translation can be inhibited by the phosphorylation of initiation factor 2.	Biochemistry_Lippinco. Treatment: KL is prescribed doxycycline, an antibiotic in the tetracycline family. Monitoring of KL will continue until all symptoms have completely resolved. Blood is drawn for clinical laboratory tests. Prognosis: Patients treated with the appropriate antibiotic in the early stages of Lyme disease typically recover quickly and completely. Case-Related Questions: Choose the ONE best answer. Q1. Antibiotics in the tetracycline class inhibit protein synthesis (translation) at the initiation step. Which of the following statements about translation is correct? A. In eukaryotic translation, the initiating amino acid is formylated methionine. B. Only the charged initiating transfer RNA goes directly to the ribosomal A site. C. Peptidyltransferase is a ribozyme that forms the peptide bond between two amino acids. D. Prokaryotic translation can be inhibited by the phosphorylation of initiation factor 2.
Biochemistry_Lippincott_1909	Biochemistry_Lippinco	C. Peptidyltransferase is a ribozyme that forms the peptide bond between two amino acids. D. Prokaryotic translation can be inhibited by the phosphorylation of initiation factor 2. E. Termination of translation is independent of guanosine triphosphate hydrolysis. F. The Shine-Dalgarno sequence facilitates the binding of the large ribosomal subunit to eukaryotic messenger RNA (mRNA). Q2. The Centers for Disease Control and Prevention recommends a two-tier testing procedure for Lyme disease that involves a screening enzyme-linked immunosorbent assay (ELISA) followed by a confirmatory western blot analysis on any sample with a positive or equivocal ELISA result. Which of the following statements about these testing procedures is correct? A. Both techniques are used to detect specific mRNA. B. Both techniques involve the use of antibodies. C. ELISA requires the use of electrophoresis.	Biochemistry_Lippinco. C. Peptidyltransferase is a ribozyme that forms the peptide bond between two amino acids. D. Prokaryotic translation can be inhibited by the phosphorylation of initiation factor 2. E. Termination of translation is independent of guanosine triphosphate hydrolysis. F. The Shine-Dalgarno sequence facilitates the binding of the large ribosomal subunit to eukaryotic messenger RNA (mRNA). Q2. The Centers for Disease Control and Prevention recommends a two-tier testing procedure for Lyme disease that involves a screening enzyme-linked immunosorbent assay (ELISA) followed by a confirmatory western blot analysis on any sample with a positive or equivocal ELISA result. Which of the following statements about these testing procedures is correct? A. Both techniques are used to detect specific mRNA. B. Both techniques involve the use of antibodies. C. ELISA requires the use of electrophoresis.
Biochemistry_Lippincott_1910	Biochemistry_Lippinco	A. Both techniques are used to detect specific mRNA. B. Both techniques involve the use of antibodies. C. ELISA requires the use of electrophoresis. D. Western blots require use of the polymerase chain reaction. Q3. Why are eukaryotic cells unaffected by antibiotics in the tetracycline class? Case 3: Blood on the Toothbrush Patient Presentation: LT is an 84-year-old man whose gums have been bleeding for several months. Focused History: LT is a widower and lives alone in a suburban community on the East Coast. He no longer drives. His two children live on the West Coast and come east infrequently. Since the death of his wife 11 months ago, he has been isolated and finds it hard to get out of the house. His appetite has changed, and he is content with cereal, coffee, and packaged snacks. Chewing is difficult.	Biochemistry_Lippinco. A. Both techniques are used to detect specific mRNA. B. Both techniques involve the use of antibodies. C. ELISA requires the use of electrophoresis. D. Western blots require use of the polymerase chain reaction. Q3. Why are eukaryotic cells unaffected by antibiotics in the tetracycline class? Case 3: Blood on the Toothbrush Patient Presentation: LT is an 84-year-old man whose gums have been bleeding for several months. Focused History: LT is a widower and lives alone in a suburban community on the East Coast. He no longer drives. His two children live on the West Coast and come east infrequently. Since the death of his wife 11 months ago, he has been isolated and finds it hard to get out of the house. His appetite has changed, and he is content with cereal, coffee, and packaged snacks. Chewing is difficult.
Biochemistry_Lippincott_1911	Biochemistry_Lippinco	Pertinent Findings: The physical examination was remarkable for the presence of swollen dark-colored gums (see image at right). Several of LT’s teeth were loose, including one that anchors his dental bridge. Several black and blue marks (ecchymoses) were noted on the legs, and an unhealed sore was present on the right wrist. Inspection of his scalp revealed tiny red spots (petechiae) around some of the hair follicles. Blood was drawn for testing. Results of tests on LT’s blood: The test for blood in his stool (occult blood test) was negative. Results of follow-up tests (obtained several days after the appointment) included the following: H = High; L = Low. Diagnosis: LT has vitamin C deficiency with a microcytic, hypochromic anemia secondary to the deficiency. Treatment: LT was prescribed vitamin C (as oral ascorbic acid) and iron (as oral ferrous sulfate) supplements. He will also be referred to social services. Prognosis: The prognosis for recovery is excellent.	Biochemistry_Lippinco. Pertinent Findings: The physical examination was remarkable for the presence of swollen dark-colored gums (see image at right). Several of LT’s teeth were loose, including one that anchors his dental bridge. Several black and blue marks (ecchymoses) were noted on the legs, and an unhealed sore was present on the right wrist. Inspection of his scalp revealed tiny red spots (petechiae) around some of the hair follicles. Blood was drawn for testing. Results of tests on LT’s blood: The test for blood in his stool (occult blood test) was negative. Results of follow-up tests (obtained several days after the appointment) included the following: H = High; L = Low. Diagnosis: LT has vitamin C deficiency with a microcytic, hypochromic anemia secondary to the deficiency. Treatment: LT was prescribed vitamin C (as oral ascorbic acid) and iron (as oral ferrous sulfate) supplements. He will also be referred to social services. Prognosis: The prognosis for recovery is excellent.
Biochemistry_Lippincott_1912	Biochemistry_Lippinco	Prognosis: The prognosis for recovery is excellent. Case-Related Questions: Choose the ONE best answer. Q1. Which of the following statements about vitamin C is correct? Vitamin C is: A. a competitor of iron absorption in the intestine. B. a fat-soluble vitamin with a 3-month supply typically stored in adipose tissue. C. a coenzyme in several enzymic reactions such as the hydroxylation of proline. D. required for the cross-linking of collagen. Q2. In contrast to the microcytic anemia characteristic of iron deficiency (common in older adults), a macrocytic anemia is seen with deficiencies of vitamin B12 and/or folic acid. These vitamin deficiencies are also common in older adults. Which of the following statements concerning these vitamins is correct? A. An inability to absorb B12 results in pernicious anemia. B. Both vitamins cause changes in gene expression. C. Folic acid plays a key role in energy metabolism in most cells.	Biochemistry_Lippinco. Prognosis: The prognosis for recovery is excellent. Case-Related Questions: Choose the ONE best answer. Q1. Which of the following statements about vitamin C is correct? Vitamin C is: A. a competitor of iron absorption in the intestine. B. a fat-soluble vitamin with a 3-month supply typically stored in adipose tissue. C. a coenzyme in several enzymic reactions such as the hydroxylation of proline. D. required for the cross-linking of collagen. Q2. In contrast to the microcytic anemia characteristic of iron deficiency (common in older adults), a macrocytic anemia is seen with deficiencies of vitamin B12 and/or folic acid. These vitamin deficiencies are also common in older adults. Which of the following statements concerning these vitamins is correct? A. An inability to absorb B12 results in pernicious anemia. B. Both vitamins cause changes in gene expression. C. Folic acid plays a key role in energy metabolism in most cells.
Biochemistry_Lippincott_1913	Biochemistry_Lippinco	A. An inability to absorb B12 results in pernicious anemia. B. Both vitamins cause changes in gene expression. C. Folic acid plays a key role in energy metabolism in most cells. D. Treatment with methotrexate can result in toxic levels of the coenzyme form of folic acid. E. Vitamin B12 is the coenzyme for enzymes catalyzing amino acid deaminations, decarboxylations, and transaminations. Q3. How do hemolytic anemias differ from nutritional anemias? Case 4: Rapid Heart Rate, Headache, and Sweating Patient Presentation: BE is a 45-year-old woman who presents with concerns about sudden (paroxysmal), intense, brief episodes of headache, sweating (diaphoresis), and a racing heart (palpitations).	Biochemistry_Lippinco. A. An inability to absorb B12 results in pernicious anemia. B. Both vitamins cause changes in gene expression. C. Folic acid plays a key role in energy metabolism in most cells. D. Treatment with methotrexate can result in toxic levels of the coenzyme form of folic acid. E. Vitamin B12 is the coenzyme for enzymes catalyzing amino acid deaminations, decarboxylations, and transaminations. Q3. How do hemolytic anemias differ from nutritional anemias? Case 4: Rapid Heart Rate, Headache, and Sweating Patient Presentation: BE is a 45-year-old woman who presents with concerns about sudden (paroxysmal), intense, brief episodes of headache, sweating (diaphoresis), and a racing heart (palpitations).
Biochemistry_Lippincott_1914	Biochemistry_Lippinco	Patient Presentation: BE is a 45-year-old woman who presents with concerns about sudden (paroxysmal), intense, brief episodes of headache, sweating (diaphoresis), and a racing heart (palpitations). Focused History: BE reports that the attacks started ~3 weeks ago. They last from 2 to 10 minutes, during which time she feels quite anxious. During the attacks, it feels as though her heart is skipping beats (arrhythmia). At first, she thought the attacks were related to recent stress at work and maybe even menopause. The last time it happened, she was in a pharmacy and had her blood pressure taken. She was told it was 165/110 mm Hg. BE notes that she has lost weight (~8 lbs) in this period even though her appetite has been good.	Biochemistry_Lippinco. Patient Presentation: BE is a 45-year-old woman who presents with concerns about sudden (paroxysmal), intense, brief episodes of headache, sweating (diaphoresis), and a racing heart (palpitations). Focused History: BE reports that the attacks started ~3 weeks ago. They last from 2 to 10 minutes, during which time she feels quite anxious. During the attacks, it feels as though her heart is skipping beats (arrhythmia). At first, she thought the attacks were related to recent stress at work and maybe even menopause. The last time it happened, she was in a pharmacy and had her blood pressure taken. She was told it was 165/110 mm Hg. BE notes that she has lost weight (~8 lbs) in this period even though her appetite has been good.
Biochemistry_Lippincott_1915	Biochemistry_Lippinco	Pertinent Findings: The physical examination was remarkable for BE’s thin, pale appearance. Blood pressure was elevated (150/100 mm Hg), as was the heart rate (110–120 beats/minute). Based on BE’s history, blood levels of normetanephrine and metanephrine were ordered. They were found to be elevated. Diagnosis: BE has a pheochromocytoma, a rare catecholamine-secreting tumor of the adrenal medulla. Treatment: Imaging studies of the abdomen were done to locate the tumor. Surgical resection of the tumor was performed. The tumor was found to be nonmalignant. Follow-up measurement of plasma metanephrines was performed 2 weeks later and was in the normal range. Prognosis: The 5-year survival rate for nonmalignant pheochromocytomas is >95%. Case-Related Questions: Choose the ONE best answer. Q1. Pheochromocytomas secrete norepinephrine (NE) and epinephrine. Which of the following statements concerning the synthesis and degradation of these two biogenic amines is correct?	Biochemistry_Lippinco. Pertinent Findings: The physical examination was remarkable for BE’s thin, pale appearance. Blood pressure was elevated (150/100 mm Hg), as was the heart rate (110–120 beats/minute). Based on BE’s history, blood levels of normetanephrine and metanephrine were ordered. They were found to be elevated. Diagnosis: BE has a pheochromocytoma, a rare catecholamine-secreting tumor of the adrenal medulla. Treatment: Imaging studies of the abdomen were done to locate the tumor. Surgical resection of the tumor was performed. The tumor was found to be nonmalignant. Follow-up measurement of plasma metanephrines was performed 2 weeks later and was in the normal range. Prognosis: The 5-year survival rate for nonmalignant pheochromocytomas is >95%. Case-Related Questions: Choose the ONE best answer. Q1. Pheochromocytomas secrete norepinephrine (NE) and epinephrine. Which of the following statements concerning the synthesis and degradation of these two biogenic amines is correct?
Biochemistry_Lippincott_1916	Biochemistry_Lippinco	Q1. Pheochromocytomas secrete norepinephrine (NE) and epinephrine. Which of the following statements concerning the synthesis and degradation of these two biogenic amines is correct? A. The substrate for their synthesis is tryptophan, which is hydroxylated to 3,4-dihydroxyphenylalanine (DOPA) by tetrahydrobiopterin-requiring tryptophan hydroxylase. B. The conversion of DOPA to dopamine utilizes a pyridoxal phosphate– requiring carboxylase. C. The conversion of NE to epinephrine requires vitamin C. D. Degradation involves methylation by catechol-O-methyltransferase and produces normetanephrine from NE and metanephrine from epinephrine. E. Normetanephrine and metanephrine are oxidatively deaminated to homovanillic acid by monoamine oxidase. Q2. Which of the following statements concerning the actions of epinephrine and/or NE are correct? A. NE functions as a neurotransmitter and a hormone.	Biochemistry_Lippinco. Q1. Pheochromocytomas secrete norepinephrine (NE) and epinephrine. Which of the following statements concerning the synthesis and degradation of these two biogenic amines is correct? A. The substrate for their synthesis is tryptophan, which is hydroxylated to 3,4-dihydroxyphenylalanine (DOPA) by tetrahydrobiopterin-requiring tryptophan hydroxylase. B. The conversion of DOPA to dopamine utilizes a pyridoxal phosphate– requiring carboxylase. C. The conversion of NE to epinephrine requires vitamin C. D. Degradation involves methylation by catechol-O-methyltransferase and produces normetanephrine from NE and metanephrine from epinephrine. E. Normetanephrine and metanephrine are oxidatively deaminated to homovanillic acid by monoamine oxidase. Q2. Which of the following statements concerning the actions of epinephrine and/or NE are correct? A. NE functions as a neurotransmitter and a hormone.
Biochemistry_Lippincott_1917	Biochemistry_Lippinco	Q2. Which of the following statements concerning the actions of epinephrine and/or NE are correct? A. NE functions as a neurotransmitter and a hormone. B. They are initiated by autophosphorylation of select tyrosine residues in their receptors. C. They are mediated by binding to adrenergic receptors, which are a class of nuclear receptors. D. They result in the activation of glycogen and triacylglycerol synthesis. Q3. NE bound to certain receptors causes vasoconstriction and an increase in blood pressure. Why might NE be used clinically in the treatment of septic shock? Case 5: Sun Sensitivity Patient Presentation: AZ is a 6-year-old boy who is being evaluated for freckle-like areas of hyperpigmentation on his face, neck, forearms, and lower legs. Focused History: AZ’s father reports that the boy has always been quite sensitive to the sun. His skin turns red (erythema) and his eyes hurt (photophobia) if he is exposed to the sun for any period of time.	Biochemistry_Lippinco. Q2. Which of the following statements concerning the actions of epinephrine and/or NE are correct? A. NE functions as a neurotransmitter and a hormone. B. They are initiated by autophosphorylation of select tyrosine residues in their receptors. C. They are mediated by binding to adrenergic receptors, which are a class of nuclear receptors. D. They result in the activation of glycogen and triacylglycerol synthesis. Q3. NE bound to certain receptors causes vasoconstriction and an increase in blood pressure. Why might NE be used clinically in the treatment of septic shock? Case 5: Sun Sensitivity Patient Presentation: AZ is a 6-year-old boy who is being evaluated for freckle-like areas of hyperpigmentation on his face, neck, forearms, and lower legs. Focused History: AZ’s father reports that the boy has always been quite sensitive to the sun. His skin turns red (erythema) and his eyes hurt (photophobia) if he is exposed to the sun for any period of time.
Biochemistry_Lippincott_1918	Biochemistry_Lippinco	Pertinent Findings: The physical examination was remarkable for the presence of thickened, scaly areas (actinic keratosis) and hyperpigmented areas on skin exposed to ultraviolet (UV) radiation from the sun. Small dilated blood vessels (telangiectasia) were also seen. Tissue from several sites on his face was biopsied, and two were later determined to be squamous cell carcinomas. Diagnosis: AZ has xeroderma pigmentosum, a rare defect in nucleotide excision repair of DNA. Treatment: Protection from sunlight through use of sunscreens such as protective clothing that reflect UV radiation and chemicals that absorb it is essential. Frequent skin and eye examinations are recommended. Prognosis: Most patients with xeroderma pigmentosum die at an early age from skin cancers. However, survival beyond middle age is possible. Case-Related Questions: Choose the ONE best answer. Q1. Which of the following statements about DNA repair mechanisms is correct? DNA repair:	Biochemistry_Lippinco. Pertinent Findings: The physical examination was remarkable for the presence of thickened, scaly areas (actinic keratosis) and hyperpigmented areas on skin exposed to ultraviolet (UV) radiation from the sun. Small dilated blood vessels (telangiectasia) were also seen. Tissue from several sites on his face was biopsied, and two were later determined to be squamous cell carcinomas. Diagnosis: AZ has xeroderma pigmentosum, a rare defect in nucleotide excision repair of DNA. Treatment: Protection from sunlight through use of sunscreens such as protective clothing that reflect UV radiation and chemicals that absorb it is essential. Frequent skin and eye examinations are recommended. Prognosis: Most patients with xeroderma pigmentosum die at an early age from skin cancers. However, survival beyond middle age is possible. Case-Related Questions: Choose the ONE best answer. Q1. Which of the following statements about DNA repair mechanisms is correct? DNA repair:
Biochemistry_Lippincott_1919	Biochemistry_Lippinco	Case-Related Questions: Choose the ONE best answer. Q1. Which of the following statements about DNA repair mechanisms is correct? DNA repair: A. is performed only by eukaryotes. B. of double-strand breaks is error free. C. of mismatched bases involves repair of the parental strand. D. of UV radiation–induced pyrimidine dimers involves removal of a short oligonucleotide containing the dimer. E. of uracil produced by the deamination of cytosine requires the actions of endo-and exonucleases to remove the uracil base. Q2. Which one of the following statements about DNA synthesis (replication) is correct? Replication: A. in both eukaryotes and prokaryotes requires an RNA primer. B. in eukaryotes requires condensation of chromatin. C. in prokaryotes is accomplished by a single DNA polymerase. D. is initiated at random sites in the genome.	Biochemistry_Lippinco. Case-Related Questions: Choose the ONE best answer. Q1. Which of the following statements about DNA repair mechanisms is correct? DNA repair: A. is performed only by eukaryotes. B. of double-strand breaks is error free. C. of mismatched bases involves repair of the parental strand. D. of UV radiation–induced pyrimidine dimers involves removal of a short oligonucleotide containing the dimer. E. of uracil produced by the deamination of cytosine requires the actions of endo-and exonucleases to remove the uracil base. Q2. Which one of the following statements about DNA synthesis (replication) is correct? Replication: A. in both eukaryotes and prokaryotes requires an RNA primer. B. in eukaryotes requires condensation of chromatin. C. in prokaryotes is accomplished by a single DNA polymerase. D. is initiated at random sites in the genome.
Biochemistry_Lippincott_1920	Biochemistry_Lippinco	B. in eukaryotes requires condensation of chromatin. C. in prokaryotes is accomplished by a single DNA polymerase. D. is initiated at random sites in the genome. E. produces a polymer of deoxyribonucleoside monophosphates linked by 5′→3′-phosphodiester bonds. . What is the difference between DNA proofreading and repair? Case 6: Dark Urine and Yellow Sclerae Patient Presentation: JF is a 13-year-old boy who presents with fatigue and yellow sclerae. Focused History: JF began treatment ~4 days ago with a sulfonamide antibiotic and a urinary analgesic for a urinary tract infection. He had been told that his urine would change color (become reddish) with the analgesic, but he reports that it has gotten darker (more brownish) over the last 2 days. Last night, his mother noticed that his eyes had a yellow tint. JF says he feels as though he has no energy.	Biochemistry_Lippinco. B. in eukaryotes requires condensation of chromatin. C. in prokaryotes is accomplished by a single DNA polymerase. D. is initiated at random sites in the genome. E. produces a polymer of deoxyribonucleoside monophosphates linked by 5′→3′-phosphodiester bonds. . What is the difference between DNA proofreading and repair? Case 6: Dark Urine and Yellow Sclerae Patient Presentation: JF is a 13-year-old boy who presents with fatigue and yellow sclerae. Focused History: JF began treatment ~4 days ago with a sulfonamide antibiotic and a urinary analgesic for a urinary tract infection. He had been told that his urine would change color (become reddish) with the analgesic, but he reports that it has gotten darker (more brownish) over the last 2 days. Last night, his mother noticed that his eyes had a yellow tint. JF says he feels as though he has no energy.
Biochemistry_Lippincott_1921	Biochemistry_Lippinco	Pertinent Findings: The physical examination was remarkable for JF’s pale appearance, mild scleral icterus (jaundice), mild splenomegaly, and increased heart rate (tachycardia). JF’s urine tested positive for hemoglobin (hemoglobinuria). A peripheral blood smear reveals a lower-than-normal number of red blood cells (RBC), with some containing precipitated hemoglobin (Heinz bodies; see image at right), and a higher-than-normal number of reticulocytes (immature RBC). Results of the complete blood count (CBC) and blood chemistry tests are pending. Diagnosis: JF has glucose 6-phosphate dehydrogenase (G6PD) deficiency, an X-linked disorder that causes hemolysis (RBC lysis).	Biochemistry_Lippinco. Pertinent Findings: The physical examination was remarkable for JF’s pale appearance, mild scleral icterus (jaundice), mild splenomegaly, and increased heart rate (tachycardia). JF’s urine tested positive for hemoglobin (hemoglobinuria). A peripheral blood smear reveals a lower-than-normal number of red blood cells (RBC), with some containing precipitated hemoglobin (Heinz bodies; see image at right), and a higher-than-normal number of reticulocytes (immature RBC). Results of the complete blood count (CBC) and blood chemistry tests are pending. Diagnosis: JF has glucose 6-phosphate dehydrogenase (G6PD) deficiency, an X-linked disorder that causes hemolysis (RBC lysis).
Biochemistry_Lippincott_1922	Biochemistry_Lippinco	Diagnosis: JF has glucose 6-phosphate dehydrogenase (G6PD) deficiency, an X-linked disorder that causes hemolysis (RBC lysis). Treatment: G6PD deficiency can result in a hemolytic anemia in affected individuals exposed to oxidative agents. JF will be switched to a different antibiotic. He will be advised that he is susceptible to certain drugs (for example, sulfa drugs), foods (fava or broad beans), and certain chemicals (for example, naphthalene), and must avoid exposure to them. Prognosis: In the absence of exposure to oxidative agents, G6PD deficiency does not cause mortality or significant morbidity. Case-Related Questions: Choose the ONE best answer. Q1. G6PD catalyzes the regulated step in the pentose phosphate pathway. Which of the following statements concerning G6PD and the pentose phosphate pathway is correct? A. Deficiency of G6PD occurs only in RBC. B. Deficiency of G6PD results in an inability to keep glutathione in its functional, reduced form.	Biochemistry_Lippinco. Diagnosis: JF has glucose 6-phosphate dehydrogenase (G6PD) deficiency, an X-linked disorder that causes hemolysis (RBC lysis). Treatment: G6PD deficiency can result in a hemolytic anemia in affected individuals exposed to oxidative agents. JF will be switched to a different antibiotic. He will be advised that he is susceptible to certain drugs (for example, sulfa drugs), foods (fava or broad beans), and certain chemicals (for example, naphthalene), and must avoid exposure to them. Prognosis: In the absence of exposure to oxidative agents, G6PD deficiency does not cause mortality or significant morbidity. Case-Related Questions: Choose the ONE best answer. Q1. G6PD catalyzes the regulated step in the pentose phosphate pathway. Which of the following statements concerning G6PD and the pentose phosphate pathway is correct? A. Deficiency of G6PD occurs only in RBC. B. Deficiency of G6PD results in an inability to keep glutathione in its functional, reduced form.