Introduction to Biochemistry

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1. A drug which prevents uric acid synthesis by inhibiting the enzyme xanthine oxidase is
(A) Aspirin
(B) Allopurinol

(C) Colchicine
(D) Probenecid

2. Which of the following is required for crystallization and storage of the hormone insulin?
(A) Mn++
(B) Mg++

(C) Ca++
(D) Zn++


3. Oxidation of which substance in the body yields the most calories
(A) Glucose
(B) Glycogen

(C) Protein
(D) Lipids


4. Milk is deficient in which vitamins?
(A) Vitamin C
(B) Vitamin A

(C) Vitamin B2
(D) Vitamin K


5. Milk is deficient of which mineral?
(A) Phosphorus
(B) Sodium

(C) Iron
(D) Potassium


6. Synthesis of prostaglandinsis is inhibited by
(A) Aspirin
(B) Arsenic

(C) Fluoride
(D) Cyanide


7. HDL is synthesized and secreted from
(A) Pancreas
(B) Liver

(C) Kidney
(D) Muscle

8. Which are the cholesterol esters that enter cells through the receptor-mediated endocytosis of lipoproteins hydrolyzed?
(A) Endoplasmin reticulum
(B) Lysosomes
(C) Plasma membrane receptor
(D) Mitochondria


9. Which of the following phospholipids is localized to a greater extent in the outer leaflet of the membrane lipid bilayer?
(A) Choline phosphoglycerides
(B) Ethanolamine phosphoglycerides
(C) Inositol phosphoglycerides
(D) Serine phosphoglycerides


10. All the following processes occur rapidly in the membrane lipid bilayer except
(A) Flexing of fatty acyl chains
(B) Lateral diffusion of phospholipids
(C) Transbilayer diffusion of phopholipids
(D) Rotation of phospholipids around their long axes


11. Which of the following statement is correct about membrane cholesterol?
(A) The hydroxyl group is located near the centre of the lipid layer
(B) Most of the cholesterol is in the form of a cholesterol ester
(C) The steroid nucleus form forms a rigid, planar structure
(D) The hydrocarbon chain of cholesterol projects into the extracellular fluid

12. Which one is the heaviest particulate component of the cell?
(A) Nucleus
(B) Mitochondria

(C) Cytoplasm
(D) Golgi apparatus


13. Which one is the largest particulate of the cytoplasm?
(A) Lysosomes
(B) Mitochondria
(C) Golgi apparatus
(D) Entoplasmic reticulum


14. The degradative Processess are categorized under the heading of
(A) Anabolism
(B) Catabolism

(C) Metabolism
(D) None of the above


15. The exchange of material takes place
(A) Only by diffusion
(B) Only by active transport
(C) Only by pinocytosis
(D) All of these


16. The average pH of Urine is
(A) 7.0
(B) 6.0

(C) 8.0
(D) 0.0


17. The pH of blood is 7.4 when the ratio between H2CO3 and NaHCO3 is
(A) 1 : 10
(B) 1 : 20

(C) 1 : 25
(D) 1 : 30


18. The phenomenon of osmosis is opposite to that of
(A) Diffusion
(B) Effusion

(C) Affusion
(D) Coagulation


19. The surface tension in intestinal lumen between fat droplets and aqueous medium is decreased by
(A) Bile Salts
(B) Bile acids

(C) Conc. H2SO4
(D) Acetic acid


20. Which of the following is located in the mitochondria?
(A) Cytochrome oxidase
(B) Succinate dehydrogenase
(D) Dihydrolipoyl dehydrogenase
(C) All of these

21. The most active site of protein synthesis is the
(A) Nucleus
(B) Ribosome

(C) Mitochondrion
(D) Cell sap


22. The fatty acids can be transported into
and out of mitochondria through
(A) Active transport
(B) Facilitated transfer
(C) Non-facilitated transfer
(D) None of these


23. Mitochondrial DNA is
(A) Circular double stranded
(B) Circular single stranded
(C) Linear double helix
(D) None of these


24. The absorption of intact protein from the gut in the foetal and newborn animals takes place by
(A) Pinocytosis
(B) Passive diffusion

(C) Simple diffusion
(D) Active transport


25. The cellular organelles called “suicide bags” are
(A) Lysosomes
(B) Ribosomes

(C) Nucleolus
(D) Golgi’s bodies


26. From the biological viewpoint, solutions can be grouped into
(A) Isotonic solution
(B) Hypotonic solutions
(C) Hypertonic solution
(D) All of these


27. Bulk transport across cell membrane is accomplished by
(A) Phagocytosis
(B) Pinocytosis

(C) Extrusion
(D) All of these


28. The ability of the cell membrane to act as a selective barrier depends upon
(A) The lipid composition of the membrane
(B) The pores which allows small molecules
(C) The special mediated transport systems
(D) All of these

29. Carrier protein can
(A) Transport only one substance
(B) Transport more than one substance
(C) Exchange one substance to another
(D) Perform all of these functions


30. A lipid bilayer is permeable to
(A) Urea
(B) Fructose

(C) Glucose
(D) Potassium

31. The Golgi complex
(A) Synthesizes proteins
(B) Produces ATP
(C) Provides a pathway for transporting chemicals
(D) Forms glycoproteins


32. The following points about microfilaments are true except
(A) They form cytoskeleton with microtubules
(B) They provide support and shape
(C) They form intracellular conducting channels
(D) They are involved in muscle cell contraction


33. The fo l low ing substances are ce l l inclusions except
(A) Melanin
(B) Glycogen

(C) Lipids
(D) Centrosome


34. Fatty acids can be transported into and out of cell membrane by
(A) Active transport
(B) Facilitated transport

(C) Diffusion
(D) Osmosis

35. Enzymes catalyzing electron transport are present mainly in the
(A) Ribosomes
(B) Endoplasmic reticulum
(C) Lysosomes
(D) Inner mitochondrial membrane


36. Mature erythrocytes do not contain
(A) Glycolytic enzymes
(B) HMP shunt enzymes

(C) Pyridine nucleotide
(D) ATP


37. In mammalian cells rRNA is produced mainly in the
(A) Endoplasmic reticulum
(B) Ribosome
(C) Nucleolus
(D) Nucleus


38. Genetic information of nuclear DNA is transmitted to the site of protein synthesis by
(A) rRNA
(B) mRNA

(C) tRNA
(D) Polysomes


39. The power house of the cell is
(A) Nucleus
(B) Cell membrane

(C) Mitochondria
(D) Lysosomes


40. The d igest ive enzymes of ce l lu lar compounds are confined to
(A) Lysosomes
(B) Ribosomes

(C) Peroxisomes
(D) Polysomes

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Dr. Ahmed Hafez

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