"oddissy4u" wrote:
01. Endogenous opioids are
A. Insulin antagonist
B. metabolites of morphine.
C. opium-like compounds produced by the brain.
D. opiate antagonists which block opioid receptors.
E. a recently discovered class of transmitter substances.

my answer: C

02. Cholesterol is returned to liver by:
A. High density lipoproteins (HDLs)
B. Very low density lipoproteins (VDLs)
C. Low density lipoproteins (LDLs)
D. Chylomicrons
E. Chylomicron remnats

A


03. Non-steroidal anti-inflammatory agents
A. activate the hydrolysis of polyunsaturated fatty acids from membrane phospholipids.
B. inhibit the conversion of arachidonic acid to oxidized, cyclized products.
C. are agonists of eicosanoids in their binding to nuclear receptors.
D. are antagonists of prostaglandins in their binding to membrane receptors.

B


04. Mutations that affect the stability of enzymes are often found to affect red blood cells more than other cell types. The best explanation for this is that
A. hemoglobin causes instability of these enzymes.
B. red blood cells have leaky membranes.
C. red blood cells are unable to replace inactivated enzymes.
D. most red blood cell enzymes are unique to the red blood cell.

D? I know Pyruvate kinase in RBC is different from other cells , hence we dont find much of affecting other organs in PK deficiency.....


05. Proteins synthesized in the liver include all the following EXCEPT:
A. immunoglobulins.
B. blood clotting factors
C. protease inhibitors.
D. Lipoproteins
E. albumin.

A (bone marrow)

06. All of the following promote activation of muscle contraction EXCEPT
A. Binding of myosin to actin.
B. Opening of the sarcoplasmic reticulum Ca channel.
C. Ca2+ binding to troponin C.
D. Opening of Na channels.
E. Ca2+ binding to the Ca2+-ATPase.

E?

07. How does fetal hemoglobin (Hb F) differ from normal adult hemoglobin (Hb A)?
A. A histidine residue in Hb A is replaced with a neutral amino acid in Hb F.
B. Hb F has a greater affinity for CO.
C. Hb F exhibits enhanced oxygen unloading versus Hb A at the same pO2
D. An alpha chain lysine residue in Hb A is replaced with a neutral amino acid in Hb F.
E. Hb F has a greater tendency to associate in the deoxygenated state.

A (Histidine in beta chain is replaced with Serine in gamma)

08. Patient has target cells, nucleated RBCs, microcytic hypochromic anemia and a positive family history; what is the investigation of choice?
A. Sucrose lysis test
B. Coombs test
C. Osmotic fragility
D. Iron & Total Iron Binding Capacity
E. Hb Electrophoresis

E. suspecting thallesemia

09. A Child was weaned from breast milk on the fifth day and was given sugar cane juice. The child developed hypoglycemia and hepatomegaly. Biochemical examination showed hypophosphatemia and reducing substances in urine. The child is probably suffering from which of the following enzyme deficiencies
A. Beta galactosidase
B. Aldolase
C. Fructokinase
D. Glucose 6 phosphatase

D

10. some serine proteases are useful in clearing blood clots that occur in myocardial infarcation EXCEPT:
A. streptokinase
B. asparginase
C. tissue plasminogen activator
D. urokinase

B (all others are used , asparaginase is anti-cancer therapy)

11. In the digestive tract, disaccharides such as sucrose are hydrolyzed to monosaccharides mainly by enzymes located in the
A. saliva.
B. gastric secretions.
C. lumen of the small intestine.
D. brush border of the small intestine.
E. lumen of the large intestine.

D

12. In mature erythrocytes, enzyme deficiencies in the glycolytic pathway can affect all of the following EXCEPT
A. transport of K+.
B. maintenance of cellular shape.
C. protein synthesis
D. synthesis of glutathione (reduced plus oxidized).
E. synthesis of 2,3 bisphosphoglycerate.

C (no nucleus or any protein systhesis)

13. Insulin promotes the uptake of glucose by muscle cells by
A. activating a Na+ -glucose contransporter.
B. activating the synthesis of a glucose transport protein.
C. inhibiting the effects of the cAMP dependent protein kinase.
D. causing an increase in the number of glucose trasport proteins on the cell membrane.

D (glut 4 receptors)

14. Insulin promotes glycogen synthesis in the liver by:
A. inhibiting glycogen synthase.
B. binding to phosphorylase.
C. causing the dephosphorylation of both phosphorylase and glycogen synthase
D. activating phosphorylase.
E. facilitating the transport of glucose into the cell.

C (it dephosphorylates, while glucagon phosphorylates)

15. If the production of Very Low Density Lipoproteins (VLDL) by the liver was stopped there would be several consequences. However, what would you NOT expect to be one of those consequences.
A. Peripheral tissues would increase their synthesis of cholesterol
B. The concentration of Low Density Lipoproteins (LDL) in the blood would decrease
C. It would still be possible to get dietary fat to adipose tissue
D. Fewer LDL receptors would be expressed on the surface of peripheral tissues
E. The excretion of bile salts and cholesterol into the gallbladder would increase.

D ( I think the concept is similar to giving a STATIN, it will decrease cholesterol synthesis in liver and so increase the LDL receptors on liver... hope I am right!)

16. A fatty acid mobilized from adipose tissue will be transported to skeletal muscle as
A. an acylcarnitine.
B. an anion bound to albumin.
C. a coenzyme A ester bound to transferrin.
D. a component of a lipoprotein triacylglycerol
E. as a cation boud to gamma globulin.

D ( i hope)

17. Hartnup's disease results from a defect in
A. a membrane transport system specific for tryptophan.
B. absorption of tyrosine.
C. decarboxylation of an alpha-keto acid.
D. the membrane transport system of neutral amino acids.
E. hydrolysis of small peptides.

A

18. The chemotherapeutic drug methotrexate reduces DNA synthesis by inhibiting:
A. ribonucleotide reductase.
B. dihydrofolate reductase.
C. glutathione reductase.
D. HMG-CoA reductase.
E. thioredoxin reductase.

B

19. If a person absorbs excessive amounts of iron, the condition is called:
A. muscle rigor.
B. anemia.
C. hemochromatosis.
D. the hemoglobin syndrome.
E. Hemolytic jundice

C (easy one!)

20. A child shows poor appetite, lethargy, a dry, scaly dermatitis (even on unexposed skin), growth retardation, a poorly healing wound, and hypogonadism. This patient could best be treated with oral doses of
A. zinc
B. iron
C. calcium
D. molybdenum
E. cobalt

A ( http://neuro-www.mgh.harvard.edu/forum_2/Tourette...) (