DAVAO Biochem

September 28, 2017 | Author: Vince Cabahug | Category: Lipoprotein, Nucleotides, Amino Acid, Glycolysis, Metabolic Pathway
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DAVAO MEDICAL SCHOOL FOUNDATION COLLEGE OF MEDICINE DEPARTMENT OF BIOCHEMISTRY LIPID CHEMISTRY / LIPID METABOLISM OBJECTIVE: A. The students must be able to describe the chemical nature and properties of the different types of lipids and relate them to their cellular functions B.

The students must understand the biosynthesis and catabolism of the commonly occurring lipid in human cells and explain the biochemical basis of diseases associated with abnormalities in lipid transport and metabolism

1. Of the following lipoproteins, which one is inversely related to the incidence of coronary atherosclerosis? a. chylomicron b. high density lipoprotein c. intermediate lipoprotein d. low density lipoprotein e. very low density lipoprotein ( HARPER’s 25th ch 27 pp 268-271) 2. . In the shuttle of mitochondrial acetyl coenzyme A to the cytosol for fatty acid synthesis, in which step generates NADPH? a. oxaloacetate + acetyl coenzyme A  citrate b. oxaloacetate  malate c. malate  pyruvate d. pyruvate  oxaloacetate e. citrate - coenzyme A  oxaloacetate - acetyl coenzyme A ( Harper’s ch 24 pp238-239) 3. The lipoprotein that serves to transport triacylglycerol from the liver to the different extrahepatic tissues: a. chylomicrons b. high density lipoproteins c. intermediate density lipoproteins d. low density lipoproteins e. very low density lipoproteins (Harper’s Ch 27 p 268-271) 4. . Which of the following apolipoproteins serves as inhibitor of lecithin:cholesterol acyltransferase (LCAT)? a. apolipoprotein A-II b. apolipoprotein A-IV c. apolipoprotein B-48 d. apolipoprotein C-I e. apolipoprotein C-II ( Harper’s ch 27 pp 270-271) 5. . In the following steps in ketone bodies metabolism, NADH is generated in: a. acetoacetate  acetone b. acetoacetate  beta hydroxybutyrate c. acetoacetyl coenzyme A + acetyl coenzyme A  HMG coenzyme A d. beta hydroxybutyrate  acetoacetate e. HMG coenzyme A  acetoacetate + acetyl coenzyme A ( Harper’s ch 24 p 244-245) 6. Human body synthesize cholesterol de novo from acetyl coenzyme A. Cholesterol synthesis occurs in which of the following organelles? a. cytosol b. endoplasmic reticulum c. golgi apparatus d. mitochondria e. ribosomes ( Harper’s ch 28 p285) 7. . Among the following apolipoproteins, which one serves as lipid transfer protein? a. apolipoprotein A-IV b. apolipoprotein B-100 c. apolipoprotein C-III d. apolipoprotein D e. apolipoprotein E ( Harper’s ch 27 p 271) 8. Among the following conditions, which one is characterized by pathologic accumulation of galactocerebroside in the affected tissues. a. Farber's Disease b. Fabry's Disease c. Gaucher's Disease d. Krabbe's Disease e. Metachromatic Leukodystrophy ( Harper’s ch 27 p 267t) 9. . Which of the lipoproteins has the highest triacylglycerol content?

a. chylomicrons b. high density lipoproteins c. intermediate density lipoproteins d. low density lipoproteins e. very low density lipoproteins (Harper’s Ch 27 p 268-271) 10. . Ketone bodies maybe synthesized from fatty acids by which of the following organs or cells? a. skeletal muscle b. liver c. kidney d. erythrocytes e. brain (Harper’s ch 24 p242) 11. Spontaneous decarboxylation of acetoacetate results in the formation of: a. acetone b. acetyl coenzyme A c. 3-hydroxybutyrate d. malonyl coenzyme A e. propionate ( Harper’s ch 24 p 242-243) 12. Which of the lipoproteins has the highest total lipid content? a. chylomicrons b. high density lipoproteins c. intermediate density lipoproteins d. low density lipoproteins e. very low density lipoproteins ( Harper’s p 268) 13. The major site of fatty acid synthesis: a. mammary gland b. liver c. kidney d. brain e. adipose tissue (Harper’s ch 23 p 230-231) 14. Of the following lipoproteins, which one is elevated in Type I Hyperlipidemia? a. chylomicrons b. high density lipoproteins c. intermediate density lipoproteins d. low density lipoproteins e. very low density lipoproteins (Harper’s Ch 27 p 268-271) 15. Of the following lipids, which one is accumulated is tissues of patient with Tay-Sach’s Disease? a. ceramide trihexoside b. galactocerebroside sulfate c. ganglioside d. glucoceberoside e. sphingomyelin (Harper’s p 267) 16. In the separation of plasma lipoprotein by electrophoresis on agarose gel, which fraction is located closest to the negative pole? a. chylomicrons b. HDL c. LDL d. VLDL e. Triglycerides (Harper’s Ch 27 p 268-271)

17. During uncontrolled diabetes mellitus or starvation, which of the following organs utilizes ketone bodies as much as 75% for its energy substrate? a. Heart b. Brain c. Kidney d. Skeletal muscles ( Harper’s ch 29 p 301) 18. In the biosynthesis of fatty acids, what is the compound that transports the acetate group out of the mitochondria into the cytoplasm a. pyruvate b. malate c. citrate d. acyl carnitine e. acyl coenzyme A (Harper’s ch 23 p 236) 19. Activation of medium chain and short fatty acids occurs in the a. Ribosomes b. Mitochondrial matrix c. Golgi apparatus d. Endoplasmic reticulum e. Cytosol (Harper’s pp 238-239)

20. The committed step in fatty acid synthesis is the formation of a. Acetyl coenzyme A b. Acetyl acyl carrier protein c. Malonyl coenzyme A d. Malonyl acyl carrier protein ( Harper’s Ch 23 pp 230)

a. 4 hours b. 12 hours c. 24 hours d. 48 hours (Harper’s pp214-217) C. BIOENERGETICS and BIOLOGICAL OXIDATION

B. Carbohydtrate chemistry/ Carbohydrate metabolism a)


OBJECTIVES: The student must be able to describe adequately the chemical properties of carbohydrates and relate them to their cellular function The students must describe the interrelationships between the various pathways of carbohydrate metabolism and explain the biochemical basis of diseases resulting from impairment of carbohydrate metabolism

1. a D glucose and a L glucose are a. Anomers b. Epimers c. Tautomers d. Enantiomers (Berg et al BIOCHEMISTRY 5TH ED p 296) 2. This sugar derivative is produced by the reduction of the carbonyl group on a monosaccaharide a. sorbitol b. glucoronic acid c. glycoside d. gluconic acid ( Harper’s Ch 15 p 153) 3. Of the following hexoses, which is a constituent of glycolipids and glycoproteins? a. glucose b. galactose c. fructose d. xylulose ( Harper’s ch 56 p 676-677) 4. Which of the following glycosaminoglycans are found in large amount in cartilages a. Dermatan sulfate b. Keratan sulfate c. Choindroitin sulfate d. Heparan sulfate e. Hyaluronic acid ( Harper’s Ch 57 p 704) 5. The compound that is the probable causative factor in the development of cataract in patients with diabetes mellitus a. Dulcitol b. Fructose 1-phosphate c. galactose 1-phosphate d. glucose 1-phosphate e. sorbitol ( Harper’s p 228-229)

OBJECTIVES: 1. The students must understand the energy transformations known to occur in cells 1. The net ATP generated in the complete oxidation of betahydroxybutyrate is: a. 12 ATPs b. 23 ATPs c. 26 ATPs d. 36 ATPs e. 129 ATPs (Harper’s chapter 24) 2. The number of NADPH required in complete synthesis of one (1) mole of palmitic acid a. 7 b. 8 c. 12 d. 14 e. 16 (Harper’s chapter 23) 3. Major source of ATP in aerobic organisms a. direct phosphorylation b. substrate level phosphorylation c. ATP adenylation d. Oxidative phosphorylation ch 14 p137)

4. The primary pathway for the oxidation of glucose a. Embden Myerhoff pathway b. Sorbitol pathway c. Tricarboxylic acid pathway d. Pentose phosphate pathway (Harper’s ch 17 p 173) 5. In the complete oxidation of one (1) mole of palmitic acid to CO2 and H2O, the total number of ATP generated is a. 12 b. 24 c. 36 d. 129 e. 131 (Harper’s Ch 23)

6. Synonymous with Kreb’s cycle a. Pentose phosphate pathway b. Citric acid cyle c. Oxidative phosphorylation d. Embden myerhoff pathway ch 18 p 182f) 6. The glycogen storage disease resulting from the deficiency of muscle phosphorylase a. Pompe’s disease b. McArdle’s disease c. Her’s disease d. Forbe’s disease e. Andersen’s disease (Harper’s ch 20 p 206t) 7. What is the major energy source for spermatozoa in seminal fluid? a. Fructose b. galactose c. glucose d. ketone bodies e. xylulose 8. A patient is diagnosed as having von Gierke’s disease is likely to exhibit which of the following clinical manifestations a. an enlarged liver b. hyperglycemia c. hypolipidemia d. hypouricemia (Harper’s Ch 36 p 397) 9. This enzyme is common to both glycolysis and gluconeogenesis .a Glyceraldehyde 3-phosphate dehydrogenase .b glucose 6-phosphatase .c pyruvate kinase .d pyruvate carboxylase (Harper’s p 194/211)


7. Anaerobic glycolysis produces how many moles of ATP per mole of glucose? a. 2 b. 6 c. 8 d. 12 e. 24 (Harper’s ch 19 p 190-191) 8. Rate limiting enzyme and the major regulatory enzyme in glycolysis a. triose phosphate isomerase b. glyceride 3-phosphate dehydrogenase c. phosphofructokinase d. aldolase (Harper’s p 191/194) 9. Enzyme that links glycolysis and the citric acid cycle a. Pyruvate dehydrogenase b. Isocitrate dehydrogenase c. Alpha-ketoglutarate dehydrogenase d. Succinate dehydrogenase ch 29 pp 298…)


10. Oxidative phosphorylation is carried out by respiratory assembly located in a. mitochondrial matrix b. inner mitochondrial membrane c. endoplasmic reticulum d. cytosol ( Harper’s pp 126/ 137….) D. Protein and amino acid chemistry/ metabolism

10. In humans, liver glycogen stores are adequate up to how many hours without support from gluconeogenesis?





The student must be able to describe the chemical structure and properties of proteins and amino acids The student must be able to understand the principles of amino acid and protein metabolism so they can relate and apply such knowledge to the study of human health and diseases

1. Which of the following amino acid functional group pairs is not correct a) arginine:guanidine b) histidine:imidazole c) phenylalanine: hydroxyphenyl d) tryptophan : indole e) cysteine : sulfhydryl (Harper’s p 29) 2.Helical formation or Helix is a characteristic of what protein structure? a. primary b. secondary c. tertiary d. quaternary e. all of the above (Harper’s p 49) 3. Which of the following amino acids serve as the major mode of disposing ammonia from the brain? a. alanine b. glutamine c. threonine d. serine e. valine (Harper’s p 308/317) 4. Among the following amino acids, which one is converted to pyruvate through transamination reaction? a. alanine b. methionine c. threonine d. valine ( Harper’s pp315-316) 5. Which of the following amino acids is convertible to pyruvate by direct deamination? a. alanine b. cysteine c. glycine d. serine e. threonine

6.The amino acid precursor of catecholamines: a. glycine b. proline c. threonine d. tryptophan e. tyrosine ( Harper’s p 354) 7. Among the following amino acids, which one is purely ketogenic? a. isoleucine b. leucine c. phenylalanine d. threonine e. tryptophan ( Harper’s Chapter 4) 8. Urea is the major pathway of nitrogen excretion in humans. It is synthesized in the: a. brain b. intestine c. kidney d. liver e. skeletal muscle ( Harper’s pp315…) 9. Among the intermediates in urea cycle, which one provides the linkage of urea cycle and the citric acid cycle? a. Alpha ketoglutarate b. aspartate c. fumarate d. malate e. oxaloacetate (Harper’s pp319-321) 10. The following amino acid is GLYCOGENIC ONLY a. aspartate b. isoleucine c. leucine d. lysine e. tyrosine ( Harper’s Chapter 4) 11. Disorder of amino acid metabolism characterized by “Maple Syrup urine odor”: a. Alkaptonuria

b. c. d.

Isovaleic Acidemia Menke’s Disease Phenylketonuria

12. What is the Isoelectric pH of albumin? a. 4.2 b. 4.7 c. 4.9 d. 5.2 e. 5.7 13. The main mode of linkage in primary protein structure is a. hydrogen bonds b. peptide bonds c. salt bonds d. covalent disulfide bonds e. van der waals (Harper’s p 49) 14. Which of the following amino acids contain indole functional group? a. Arginine b. Histidine c. Phenylalanine d. Tryptophan e. Tyrosine (Harper’s p 29) 15. A biochemical technique used to separate molecules based on both size and charge a. gel electrophoresis b. spectrophotometry c. ultracentrifugation d. paper chromatography ( Harper’s P48/53) 16. Which of the following enzymes funnel amino nitrogen from glutamate to urea? a. glutamate transaminase a. alanine transaminase b. amino acid oxidase c. glutamate dehydratase d. glutamate dehydrogenase (Harper’s pp319-321)

17. Amino acid precursor of serotonin a. alanine b. aspartate c. tryptophan d. methionine e. tyrosine 18. The metabolism of the following amino acid leads to the production of small amounts of nicotinic acid in humans a. cysteine b. methionine c. serine d. tryptophan e. valine ( Harper’s chapter 42) 19. A metabolite of the following amino acid is a substrate for branched-chain keto-acid dehydrogenase a. arginine b. lysine c. methionine d. proline e. valine ( Harper’s chapter 4) 20. Which of the following is a non essential amino acid? a. leucine b. tyrosine c. lysine d. methionine e. valine ( Harper’s chapter 4) D. Nucleic acid chemistry/metabolism/ Genetics OBJECTIVES: 1. The student should be able to describe the structural organization of nucleosides, nucleotides and nucleic acids and relate them to their cellular functions 2. The students should discuss and understand the biochemical basis of diseases resulting from impairment in the biosynthetic and catabolic pathways of purine and pyrimidine nucleotide metabolism 1. The most abundant free nucleotide in mammalian cells a. Adenosine diphosphate b. Cyclic AMP c. Adenosine triphosphate d. Adenosine monophosphate e. Phosphoadenosine phosphosulfate ( HARPER’S 25th p. 379) 2. A purine analog which is widely used in the treatment of gout a. aspirin

b. azathioprine c. allopurinol d. 5-iododeoxyuridine e. 5-flourouracil (HARPER’S CH 35 p-382) 3. Okasaki fragments are a. short non coding DNA segments b. short DNA fragments attached to RNA primers during replication c. produced when histone biosynthesis is inhibited d. mitochondrial DNA fragments complexed with histones (HARPER’S CH 38 p- 424)

3. Nonfunctional serum enzyme that is diagnostic of obstructive liver diseases. A. acid phosphatase B. alanine aminotransferase C. alkaline phosphatase D. aspartate aminotransferase E. ceruloplasmin 4. Carbonic anhydrase requires which metal ion as cofactor a. iron b. zinc c. magnesium d. copper e. sodium,

4. RNA and DNA diifer from each other , in that: a. in DNA, the nucleotides run 5’ to 3’ direction b. in RNA, the sugar is linked to the base by an Nglycosidic linkage c. In RNA, the sugar is D-ribose d. in DNA, thymine is found instead of uracil ( HARPER’S CH 37 p 406)

5. In the effects of substrate concentration on reaction velocity, when substrate concentration is low a. the reaction velocity is zero order b. the reaction velocity is first-order c. the reaction velocity is second order d. the reaction velocity is mixed order

5. Detection of purines and pyrimidines can be done because of their strong absorption of UV light at this wavelength a. 260nm b. 650 nm c. 400nm d. 600 nm (HARPER’S p-290)

6. Which of the following is the target enzyme of an anti inflammatory drug, aspirin? a. xanthine oxidase b. transpeptidase c. HMG CoA reductase d. Cyclooxygenase e. Monoamine oxidase

6. In genetic diseases, the primary defect resides in this organelle a. endoplasmic reticulum b. nucleus c. cytoplasm d. mitochondria ( HARPER’S CH 63 P-813)


A PURINE BASE a. cytosine b. guanine c. uracil d. thymine

( HARPER’s ch 37 p 402)

8. Serves as the carrier of genetic information to the site of protein synthesis a. mRNA b. tRNA c. rRNA d. snRNA (HARPER’s ch37 p 407) 9. A synthetic nucleotide analog which exhibits antiviral activity useful in the treatment of herpetic keratitis a. azathioprine b. 5-iododeoxyuridine c. cytarabine d. mercaptopurine ( HARPER’s p 383) 10. Nucleotide derivative that acts as “ secondary messenger” a. ATP b. ADP c. c-AMP d. c-GMP e. GTP ( HARPER’s CH 35 p-380) E. ENZYMES OBJECTIVES: 1. The students must appreciate hoe protein structures of enzymes have been specifically designed to allow the catalytic action of enzymes in metabolic reactions 2. The students must understand the role of enzymes in metabolic regulation and their importance as diagnostic aids and therapeutic tools 1. Two constants are always measured whenever an enzyme is characterized. These are: a. K1 and Km b. Km and Vmax c. Q10 and Vo d. Vmax and Q10 e. Vo and K1 (Harper’s pp 95 ff ) 2. Group of enzymes that catalyze the addition or removal of water, ammonia or carbon dioxide to double bonds: a. hydrolases b. isomerases c. ligases d. lyases e. oxidoreductases

7. Effect of uncompetitive inhibitors to the Maximum velocity (Vmax) and Michaelis constant (Km) a. Vmax - none : Km – increases b. Vmax – decreases : Km – decreases c. Vmax – decreases : Km - none d. Vmax – decreases : Km- increases e. Vmax – increase : Km – none (Harper’s pp 95 ff ) 8. The quantitative value of the Michaelis constant or Km, is a measure of a. the optimum condition present in the cell b. relative affinity between the substrate and enzyme c. the velocity of the biochemical reaction d. the concentration of the enzyme present (Harper’s pp 95 ff ) 9. This enzyme is valuable in the diagnosis of metastatic carcinoma of the prostate gland. a. ceruloplasmin b. alkaline phosphatase c. lactate dehydogenase d. acid phosphatase e. aspartate aminotransferase 10. A group of enzymes that join two molecules along with breakdown of a pyrophosphate (P-P) bond a. ligase b. isomerase c. lyase d. transferase F. HORMONES/ Hormone actions OBJECTIVES: 1. The students must understand the structures, properties and the roles of hormones in the maintenance of normal body metabolism 1. Among the following hormones, which one possess antiinflammatory effect mediated through the inhibitory arachidonic acid release? a. adrenaline b. glucagon c. glucocorticosteroid d. insulin e. thyroxine

effect on

2. Of the following, which is a C-19 steroid? a. cholic acid b. cortisol c. estradiol d. progesterone e. testosterone ( Harper’s 577-578) 3. . Which of the following hormones is aromatic? a. aldosterone b. cortisol c. estradiol d. progesterone e. testosterone ( Harper’s p 577) 4. In the synthesis of estradiol which of the following hormone is its immediate precursor? a. androstenedione b. corticosterone c. pregnenolone

d. e.

progesterone testosterone

d. e.

( Harper’s pp599-601)

5. Site of aldosterone secretion in the adrenal cortex: a. zona fasciculata b. zona granulosa c. zona intima d. zona pellucida e. zona reticularis 6. Which of the following is a C-24 steroid? a. chenodeoxycholic acid b. cortisol c. estradiol d. progesterone e. testosterone (Harper’s p 292)

7. Of the following hormones, which one is an essential requirement for triacyglycerol synthesis in the adipose tissue? a. adrenaline b. cortisol c. glucagon d. insulin e. thyroxine (Harper’s p246) 8. In the adipose tissue, which of the following hormones enhances the synthesis of lipoprotein lipase? a. cortisol b. epinephrine c. glucagons d. insulin e. progesterone ( Harper’s p 246) 9. The urinary metabolite used in the diagnosis of Adrenal Pheochromocytoma: a. hydroxyindoleacetic acid (HIAA) b. hydroxytryptamine c. hydroxytryptophan d. normetanephrine e. vanillylmandelic acid (VMA) (Harper’s p 593) 10. . Which of the following is a C-18 steroid? f. chenodeoxycholic acid g. cortisol h. estradiol i. progesterone j. testosterone p577)

( Harper’s

E. VITAMINS AND MINERALS OBJECTIVES: 1. The students must understand clearly the nutritional aspects of vitamins and minerals and appreciate their role in the maintenance of normal body functions 2. The students must correlate the clinical disorders that will result from the deficiency and excesses of these vitamins with their metabolic roles in the body. 1.

An important anti oxidant because it inhibits the formation of nitrosamines during digestion a. retinol b. ascorbic acid c. tocopherol d. retinoic acid e. cobalamin (Harper’s pp640-641)


Deficiency of this may lead to anemia in the prematures due to red blood cell hemolysis a. Vit A b. Vit D c. Vit E d. Vit C e. Vit K (Harper’s pp 647-648)


A cofactor of an important enzyme of the pentose phosphate pathway, transketolase a. Thiamine b. Biotin c. Niacin d. Riboflavin e. Pantothenic acid (Harper’s pp 627)


Functions as a cofactor to a carboxylase that acts on glutamate residues of clotting factor precursor proteins a. Vitamin A b. Vitamin C c. Vitamiin E

Vitamin K Biotin

( Harper’s PP 649)


A polyisoprenoid compound containing a cyclohexenyl ring a. Folic acid b. Pyridoxine c. Ascorbic acid d. Retinol e. Biotin ( Harper’s p 642)


The earliest clinical symptom of Vitamin A deficiency a. defective night vision b. xerophtalmia c. presence of Bitots spots d. Keratomalacia e. Xerosis conjunctivae (Harper’s p 643)

7. This vitamin is important in the regulation of calcium and phosphate metabolism a. Vitamin A b. Vitamin E c. Thiamin d. Folic acid e. Vitamin D ( Harper’s p 645) 8. If a patient exhibits low activity of propionyl CoA carboxylase, therapeutic doses of which of the following might be beneficial? a. carnitine b. pantothenic acid c. biotin d. riboflavin e. niacin ( Harper’s p 635) 9. Strict vegetarians are susceptible to this kind of vitamin deficiency a. pantothenic acid b. cobalamin c. folacin d. niacin e. pyridoxine ( Harper’s p 635) 10. . Of the following, which is the most potent form of vitamin D? a. ergosterol b. cholecalciferol c. 7-dehydrocholesterol d. 25-hydroxycholecalciferol e. 1,25-dihydroxycholecalciferol ( Harper’s p 647)

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