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The answer is b. (Murray, pp 230-267. Scriver, pp 2297-2326. Sack, pp 121-138. Wilson, pp 287-320.) Untreated ethylene glycol of antifreeze can be converted to the kidney toxin oxalate crystals. This occurs by oxidation of ethylene glycol. The first committed step in this process is the oxidation of ethylene glycol to an aldehyde by alcohol dehydrogenase. This is normally the route for converting ethanol (drinking alcohol) to acetate. Patients who have ingested ethylene glycol or wood...

Dhg

The formation of P-hydroxybutyrate occurs in which of the diagrammatic structures shown in question 283 Structure A Structure B Structure C Structure D Structure E 285. Gangliosides and receptors for hormones such as glucagon can be found in which of the diagrammatic structures shown in question 283 286. A control and two patients with hyperlipidemia are studied after an overnight fast. Their plasma lipoprotein electrophoresis patterns are shown below, the control being in the middle lane....

A

Which one of the following apolipoproteins is synthesized in the liver as part of the coat of very-low-density lipoproteins (VLDLs) 270. Which of the following lipoproteins would contribute to a measurement of plasma cholesterol in a normal person following a 12-h fast a. Very-low-density lipoproteins 268. Which one of the following steps pholipid 271. Which of the following statements correctly describes the enzyme thiokinase a. It yields acetyl CoA as a product d. It forms CoA thioesters...

Questions

DIRECTIONS Each item below contains a question or incomplete statement followed by suggested responses. Select the one best response to each question. 242. A child with a large head, multiple fractures, and blue scleras (whites of the eyes) is evaluated for osteogenesis imperfecta (166200). One study involves labeling of collagen chains in tissue culture to assess their mobility by gel electrophoresis. Amino acids labeled with radioactive carbon 14 are added to the culture dishes in order to...

Answers

The answer is b. (Murray, pp 123 148. Scriver, pp 2367-2424. Sack, pp 159-175. Wilson, pp 287-317.) Although metabolic poisons do uncouple oxidation of NADH from production of ATP, the uncoupling of oxidative phosphorylation does occur under certain normal biologic conditions. In brown fat (so called because of the large number of blood vessels), oxidation is uncoupled from phosphorylation so that heat is produced. This phenomenon is observed in newborn mammals, including humans,...

E

Nervous stimulation of skeletal muscle causes the release of calcium from sarcoplasmic reticulum and leads to muscle contraction. Simultaneously, the increased calcium concentration causes a. A dramatic rise in cyclic AMP levels b. Inactivation of glycogen phosphorylase c. Activation of phosphorylase kinase d. Activation of cyclic AMP phosphodiesterase e. Activation of protein phosphatase 228. A teenage girl is brought to the medical center because of her complaints that she gets too tired...

DNA Structure Replication and Repair

DIRECTIONS Each item below contains a question or incomplete statement followed by suggested responses. Select the one best response to each question. 1. Patients with Hurler's syndrome (252800) are known to have mutations at the L-iduronidase locus. The diagnosis of Hurler's syndrome is most efficiently made by analyzing a patient's DNA for a. A region of DNA that does not encode RNA b. Alternative forms of the L-iduronidase gene c. The entire set of genes in one leukocyte d. A nucleotide...

G

The genetic code (codon assignments in messenger RNA. (Reproduced, wth permission, from Murray RK, Granner DK, Mayes PA, Rodwell VW Harper's Biochemistry, 25le.New York, McGraw-Hill, 2000 453.) The genetic code (codon assignments in messenger RNA. (Reproduced, wth permission, from Murray RK, Granner DK, Mayes PA, Rodwell VW Harper's Biochemistry, 25le.New York, McGraw-Hill, 2000 453.) 34. The answer is d. (Murray, pp 452-467. Scriver, pp 3-45. Sack, pp 1-40. Wilson, pp 101-120.) Sickle cell...

I

Disease 231000 (storage of lipids in the spleen and bone) , and takes advantage of cellular pathways that target enzymes to lysosomes. 73. The answer is c. (Murray, pp 468-487. Scriver, pp 175-192. Sack, pp 245-257. Wilson, pp 151-180.) After the locus responsible for a genetic disease is mapped to a particular chromosome region, candidate genes can be examined for molecular abnormalities in affected individuals. The connective tissue abnormalities in Stickler syndrome (108300) make the COL2A1...

Thiamine Diphosphate Activate The Aldehyde Is Transferred Beriberi

The answer is b. (Murray, pp 627-661. Scriver, pp3127-3164. Sack, pp 121-138. Wilson, pp 287-320.) Ferrous iron (Fe++) is the form absorbed in the intestine by ferritin, transported in plasma by transferrin, and stored in the liver in combination with ferritin or as hemosiderin. There is no known excretory pathway for iron, either in the ferric or ferrous form. For this reason, excessive iron uptake over a period of many years may cause hemochro-matosis (235200), the likely diagnosis for...

1

The major source of extracellular cholesterol for human tissues is a. Very-low-density lipoproteins (VLDLs) b. Low-density lipoproteins (LDLs) c. High-density lipoproteins (HDLs) 288. The synthesis of 3-hydroxy-3-methylglutaryl CoA can occur a. Only in mitochondria of all mammalian tissues b. Only in the cytosol of all mammalian tissues c. Only in the endoplasmic reticulum of all mammalian tissues d. In both the cytosol and mitochondria 289. When the liver is actively synthesizing fatty...

Which Glycosidic Cherubic Facies

Which of the following explains why individuals with hyperlipi-demia and or gout should minimize their intake of sucrose and high-fructose syrups a. Fructose is initially phosphorylated by liver fructokinase b. After initial modification, fructose is cleaved by a specific enolase c. Fructose is converted to UDP-fructose d. Fructose is ultimately converted to galactose e. Fructose can be phosphorylated by hexokinase in adipose cells 185. Glycogen synthetase, the enzyme involved in the...

EaiPia2P2

Which of the following amino acids is most compatible with an a-helical structure 110. Blood is drawn from a child with severe anemia and the hemoglobin protein is degraded for peptide and amino acid analysis. Of the results below, which change in hemoglobin primary structure is most likely to correlate with the clinical phenotype of anemia 111. An adult with mild, chronic anemia does not respond to iron supplementation. Blood is drawn and the red cell hemoglobin is analyzed. Which of the...

Xny

Autosomal recessive conditions are correctly characterized by which of the following statements a. They are often associated with deficient enzyme activity b. Both alleles contain the same mutation c. They are more variable than autosomal dominant conditions d. Most persons do not carry any abnormal recessive genes e. Affected individuals are likely to have affected offspring 402. Gardner's syndrome is an autosomal dominant condition characterized by multiple polyps of the intestines, bony...

Fad

Which one of the following enzymes requires a coenzyme derived from the vitamin whose structure is shown below d. Glucose-6-phosphate dehydrogenase 319. Coenzymes derived from the vitamin shown below are required by enzymes involved in the synthesis of which of the following 320. Coenzymes derived from the vitamin shown below are required by which one of the following enzymes e. Glyceraldehyde-3-phosphate dehydrogenase 321. Which of the structures in the figure below is involved in amino...