Lipid, Amino Acid, Nucleotide, and Nitrogen Metabolism Quiz - Part 1 (20 test)
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1. A 65-year-old Caucasian male physician comes in for his annual physical examination and is noted to have palmar erythema, tremors, and a prominent abdomen with exaggerated superficial veins. Upon gentle inquiry, he admits to having three to four beers a night for most of his career except when on call, and discloses that his father died from cirrhosis. His family practitioner obtains a hepatic function panel that includes a serum aspartate aminotransferase level (AST, also known as SGOT) of 350 U/L (normal 15-45) and a serum alanine aminotransferase (ALT, also known as SGPT) of 280 U/L (normal 10-40). Which of the following best conveys the role of transaminases such as AST and ALT and the significance of their serum elevations?
- Produce α-ketoglutarate, inhibit gluconeogenesis, and reveal liver cell death
- Produce glutamate, promote gluconeogenesis, and reveal liver cancer
- Produce urea, inhibit gluconeogenesis, and reveal liver cancer
- Remove ammonia, promote gluconeogenesis, and reveal liver cell death
- Remove ammonia, inhibit gluconeogenesis, and reveal liver cancer
2. Certain organic acidemias or fatty acid oxidation disorders will also involve elevated This relates to the location of reactions of the urea cycle, occurring in which of the following?
- In the cytosol
- In lysosomes
- In the mitochondrial matrix
- In the mitochondrial matrix and the cytosol
- In peroxisomes
3. A 23-year-old Caucasian female is found to have elevated blood pressure on her routine obstetric checkup at 8 months gestation, and testing by her obstetrician demonstrates anemia with hemolysis, elevated liver enzymes, and low platelets that are characteristic of disease represented by the acronym HELLP syndrome. The female is hospitalized and fetal maturity tests are performed that allow elective premature delivery. The female quickly recovers but the premature newborn has a dilated heart and elevated liver enzymes that are characteristic of a defect in long-chain fatty acid The potential enzyme deficiencies are those responsible for sequential oxidation of fatty acids, which include which of the following?
- Dehydrogenase, hydratase, dehydrogenase, and thiolase
- Transacylase, synthase, and reductase
- Hydratase, reductase, and thioesterase
- Thioesterase, dehydrogenase, and thiolase
- Dehydrogenase, thiolase, and thioesterase
4. A 30-year-old African American female is admitted with a diagnosis of diabetic ketoacidosis. She had onset of juvenile (type I) diabetes at age 16 and has done well until attendance at a destination wedding altered her diet and insulin Which of the following would best apply to her liver metabolism upon admission?
- Increased glucose uptake, increased fatty acid oxidation, and decreased acetone synthesis
- Increased glucose uptake, decreased fatty acid oxidation, and increased β-hydroxybutyrate synthesis
- Decreased glucose uptake, increased fatty acid oxidation, and increased acetone synthesis
- Increased glucose uptake, increased fatty acid oxidation, and increased acetoacetate synthesis
- Increased glucose uptake, increased fatty acid oxidation, and decreased acetoacetate synthesis
5. Which of the following enzymes is most important in regulating lipogenesis?
- Acetyl-CoA carboxylase
- Medium-chain acetyl-CoA dehydrogenase
- Short-chain enoyl reductase
- Long-chain enoyl hydratase
- 3-Ketoacyl reductase
6. Which of the following is the important reactive group of glutathione in its role as an antioxidant?
7. Which of the following processes generates the most ATP?
- Citric acid cycle
- Fatty acid oxidation
- Pentose phosphate pathway
8. A 3-year-old Caucasian girl is brought into the emergency room while you are on She is cold and clammy and is breathing rapidly. She is obviously confused and lethargic. Her mother indicates she has accidentally ingested automobile antifreeze while playing in the garage. Following gastrointestinal lavage and activated charcoal administration, which of the following treatments should you immediately initiate?
- Intravenous infusion of oxalic acid
- Nasogastric tube for ethanol administration
- Flushing out the bladder via a catheter
- Intramuscular injection of epinephrine
- Simply waiting and measuring vital signs
9. After finding that infants, particularly those with prematurity, are vulnerable to fatty acid deficiencies, major manufacturers began supplementing their infant formulas with these compounds. Which of the following is a nutritionally essential fatty acid along with its usual dietary source?
- Eicosapentaenoic acid—plants
- Linoleic acid—plants
- Oleic acid—animals
- Palmitoleic acid—animals
- Linolenic acid—animals
10. A 62-year-old Caucasian male develops episodes of incoordination and slurred speech. His wife notes that he seems depressed and His physician diagnoses multiple sclerosis, which is best described as which of the following?
- Demyelinating disease with loss of phospholipids and ceramide from brain and spinal cord
- Lipid storage disease with loss of sphingolipids and ceramide from brain and spinal cord
- Lipid storage disease with loss of sphingolipids and gangliosides from brain and spinal cord.
- Demyelinating disease with loss of phospholipids and sphingolipids from brain and spinal cord
- Lipid storage disease with accumulation of sphingolipids in brain
11. Children with very long or long chain fatty acid oxidation disorders are severely affected from birth, while those with short- or medium-chain oxidation defects may be asymptomatic until they have an intercurrent illness that causes prolonged fasting. The severe symptoms of longer-chain diseases are best explained by which of the following statements?
- Longer-chain fatty acids inhibit gluconeogenesis and deplete serum glucose needed for brain metabolism.
- Glycogen is the main fuel reserve of the body but is quickly depleted with fasting.
- Starch is an important source of glucose and is inhibited by high fatty acid concentrations.
- Triacylglycerols are the main fuel reserve of the body and are needed for energy production in actively metabolizing tissues.
- Longer-chain fatty acids form micelles and block synapses.
12. A 56-year-old Caucasian male with chronic alcoholism is admitted with hematochezia (bright red blood in stools) and hematemesis (bloody vomitus). Transfusions and esophageal tube pressure fail to maintain his blood pressure, and he dies from shock and cardiac failure. Autopsy would expect to show which of the following?
- Normal liver with excess chylomicrons
- Cirrhotic liver with excess HDL
- Fatty liver with excess LDL
- Fatty liver with VLDL
- Cirrhotic and fatty liver with excess triacylglycerol
13. Niemann-Pick disease (MIM*257220), like other neurolipidoses, presents in infancy or childhood with plateauing of development and neurologic The accumulating substance is a phospholipid made in which of the following steps in the figure below?
- Step A
- Step B
- Step C
- Step D
- Step E
14. A 10-year-old Caucasian girl presents with chest pain and unusual skin patches over her elbows and knees. Her father died of a heart attack at age 35 and her mother is known to have high Her physician suspects familial hypercholesterolemia (MIM*144010) in the parents with homozygous severe disease in the daughter. This disease results from mutations in the receptor for low-density lipoprotein (LDL) or the ligand portion of its apoprotein coat, which is which of the following?
15. A 45-year-old Caucasian male is found to have a serum cholesterol of 300 mg/dL (normal <200 depending on criteria) after a 12-hour Which of the following lipoproteins would contribute to plasma cholesterol following a 12-hour fast?
- Very low density lipoproteins (VLDLs) and low-density lipoproteins (LDLs)
- High-density lipoproteins (HDLs) and low-density lipoproteins (LDLs)
- Chylomicrons and very low density lipoproteins (VLDLs)
- Chylomicron remnants and very low density lipoproteins (VLDLs)
- Low-density lipoproteins (LDLs) and adipocyte lipid droplets
16. A 2-day-old Caucasian male neonate with meconium ileus (plugging of the small intestine with meconium or fetal stool) is found to have air in the bowel wall (pneumatosis intestinalis) and free air in the Antibiotics are begun for suspected peritonitis, and emergency surgery is performed to remove the diseased intestinal segment and heal the intestinal perforation that led to air in the abdomen. Because the gut must be kept at rest for healing, meconium peritonitis was usually fatal until parenteral alimentation solutions were developed. Hyperalimentation consists of essential amino acids and other metabolites that provide a positive calorie balance while keeping the bowel at rest. The alimentation solution must be kept to a minimum of metabolites because of its high osmotic load that necessitates frequent changing of intravenous sites or catherization of a large vein. Which of the following amino acids could be excluded from the alimentation solution?
17. Leukocyte samples isolated from the blood of a newborn Caucasian boy are homogenized and incubated with ganglioside GM 2. Approximately 47% of the expected normal amount of N-acetylgalactosamine is liberated during the incubation These results indicate which of the following regarding this infant?
- He is a heterozygote (carrier) for Tay-Sachs disease.
- He is homozygous for Tay-Sachs disease.
- He has Tay-Sachs syndrome.
- He will most likely have mental deficiency.
- He has relatively normal β-N-acetylhexosaminidase activity
18. A 4-year-old boy of Middle-Eastern ancestry is known to have inherited favism, a sensitivity to fava beans due to glucose-6-phosphate dehydrogenase deficiency (MIM*305900). Which of the following indicates the primary pathway affected by this deficiency and the pathway secondarily affected because one of its energy substrates will be deficient?
- Pentose phosphate pathway, fatty acid synthesis
- Pentose phosphate pathway, fatty acid oxidation
- Citric acid cycle, fatty acid oxidation
- Citric acid cycle, glycolysis
- Glycolysis, citric acid cycle
19. Which enzyme catalyzes the only step of fatty acid oxidation that requires energy?
- Acyl-CoA dehydrogenase
- Acyl-CoA synthetase
- Δ2-Enoyl-CoA hydratase
- L(+)-3-Hydroxyacyl-CoA dehydrogenase
20. Adults with liver disease or milder urea cycle defects often exhibit neurologic symptoms (confusion, memory loss, and motor incoordination) when interval high- protein meals or anorexia with protein catabolism elevates their serum Ammonia intoxication is most obvious in neonates with severe urea cycle defects, manifest by lethargy and coma. Given that the cerebral cortex is a very active tissue with high-energy requirements, which of the following consequences of hyperammonemia are most likely responsible for cerebral symptoms?
- Decreased glutamine, increased carboymal phosphate synthase activity
- Increased α-ketoglutarate, increased arginase activity
- Decreased glutamine, increased arginase activity
- Increased glutamine, increased carbamoyl phosphate synthase activity