Pharmacy Technician
Biochemistry Part .01 MCQs
| 1. Biochemistry primarily studies
a. Chemical processes in tissues b. Mechanical processes in organs c. Electrical activity of neurons d. Psychological behavior Answer: a 2. The “protoplasm” mentioned in biochemistry refers to a. Extracellular fluid b. Cell cytoplasm plus nucleus c. Collagen fibers d. Blood plasma Answer: b 3. In organized metabolic reactions we remain healthy; disorganization leads to a. Improved immunity b. Illness or death c. Faster growth d. Increased strength Answer: b 4. Biochemistry emerged as an independent discipline in the a. 18th century b. Early 19th century c. Late 19th century d. Second half of the 20th century Answer: d 5. Biochemists aided the discovery of vitamins’ roles in a. Structural proteins only b. Clinical therapies for rickets, pellagra, beriberi, scurvy, pernicious anemia c. Mechanical properties of enzymes d. DNA sequencing Answer: b 6. On hydrolysis carbohydrates yield a. Amino acids b. Polyhydroxy aldehydes or ketones c. Fatty acids d. Nucleotides Answer: b 7. General formula of a simple carbohydrate is a. CnH2n b. Cn(H2O)n c. CnH2nO d. CnO2H Answer: b 8. Rhamnose (C6H12O5) is an exception to the formula because it lacks a. Carbon b. One “H2O” unit c. Oxygen d. A ketone group Answer: b 9. Functional groups in carbohydrates include a. Amines and phosphates b. Aldehyde (-CHO) and keto (C = O) c. Sulfhydryl only d. Ether exclusively Answer: b 10. The most abundant plant polysaccharide is a. Glycogen b. Starch c. Cellulose d. Glycosaminoglycan Answer: c 11. Glucose is a(n) a. Ketose b. Disaccharide c. Aldose d. Polysaccharide Answer: c 12. Fructose is sweetest because it is a a. Monosaccharide, ketose b. Disaccharide, aldose c. Polysaccharide d. Amino sugar Answer: a 13. Sucrose on hydrolysis yields a. Two glucoses b. Glucose + fructose c. Glucose + galactose d. Two fructoses Answer: b 14. Glycogen is the storage polysaccharide in a. Plants only b. Animals only c. Both plants and animals d. Bacteria Answer: b 15. Lipids are insoluble in water but soluble in a. Ethanol b. Benzene, chloroform, ether c. Saline d. Glycerol Answer: b 16. A triglyceride is formed by esterification of fatty acids to a. Cholesterol b. Glycerol c. Sphingosine d. Phosphate Answer: b 17. Saturated fatty acids contain a. At least one double bond b. No double bonds c. A keto group d. An aromatic ring Answer: b 18. Cholesterol is a precursor for a. Vitamin C b. Steroid hormones c. DNA d. Amino acids Answer: b 19. The peptide bond links a. Two monosaccharides b. Fatty acids to glycerol c. Two amino acids d. Nucleotides Answer: c 20. Hemoglobin’s quaternary structure is composed of a. One polypeptide chain b. Two alpha and two beta chains c. RNA + protein d. Lipid + protein Answer: b 21. Enzymes are biological catalysts that a. Are consumed in reactions b. Speed up reactions without being consumed c. Lower reaction rate d. Change reaction equilibrium Answer: b 22. Most enzymes are proteins except some RNA catalysts called a. Ribozymes b. Liposomes c. Metalloproteins d. Glycoproteins Answer: a 23. Cofactors are a. Protein portions of enzymes b. Inorganic ions needed for enzyme activity c. Vitamin D derivatives d. Substrate analogues Answer: b 24. A holoenzyme = a. Apoenzyme + prosthetic group b. Enzyme – substrate complex c. Inactive precursor d. Allosteric inhibitor Answer: a 25. Michaelis–Menten kinetics describe the effect of a. pH on activity b. Substrate concentration on rate c. Temperature on rate d. Cofactor binding Answer: b 26. Digestion of starch begins with a. Pepsin in stomach b. Salivary amylase in mouth c. Lipase in duodenum d. Lactase in colon Answer: b 27. The pH optimum for pepsin is about a. 1–2 b. 4–5 c. 7–8 d. 10–11 Answer: a 28. Competitive enzyme inhibition can be overcome by a. Increasing substrate concentration b. Decreasing pH c. Lowering temperature d. Removing cofactors Answer: a 29. A vitamin is a. Produced in large amounts by humans b. An essential micronutrient c. A macronutrient d. A mineral Answer: b 30. Vitamin C deficiency causes a. Rickets b. Scurvy c. Pellagra d. Beriberi Answer: b 31. Vitamin D promotes a. Insulin secretion b. Calcium absorption in gut c. Collagen synthesis d. Red blood cell breakdown Answer: b 32. Niacin (B3) is part of the coenzymes a. FAD, FMN b. NAD, NADP c. CoA d. Thiamine pyrophosphate Answer: b 33. Pernicious anemia arises from deficiency of a. Vitamin A b. Vitamin B12 c. Vitamin C d. Vitamin K Answer: b 34. In DNA the base thymine pairs with a. Adenine b. Cytosine c. Guanine d. Uracil Answer: a 35. The enzyme that makes cDNA from mRNA is a. DNA polymerase b. RNA polymerase c. Reverse transcriptase d. Ligase Answer: c 36. A buffer system in plasma is a. NaCl–HCl b. HCO3−–H2CO3 c. NH4+–NH3 d. H2O–O2 Answer: b 37. Respiratory compensation for acidosis involves a. Increasing ventilation to blow off CO2 b. Retaining CO2 c. Excreting HCO3− d. Producing ketones Answer: a 38. Major intracellular cation is a. Na+ b. K+ c. Ca2+ d. Cl− Answer: b 39. Insulin is secreted by the a. Alpha cells of pancreas b. Beta cells of pancreas c. Adrenal cortex d. Parathyroids Answer: b 40. Thyroid hormone is derived from a. Tryptophan b. Tyrosine c. Histidine d. Phenylalanine Answer: b 41. Oxytocin causes milk ejection by acting on a. Myoepithelial cells b. Hepatocytes c. Neurons d. Chondrocytes Answer: a 42. Human growth hormone is a a. Steroid b. Peptide c. Amino acid d. Lipid Answer: b 43. Peptide bond formation releases a. Water b. CO2 c. NH3 d. H2O2 Answer: a 44. The P–O bond in ATP is a. Low energy b. High energy c. Ionic d. Peptide Answer: b 45. The net ATP yield from oxidation of one glucose (glycolysis + TCA + ETC) is about a. 4 b. 12 c. 30–32 d. 100 Answer: c 46. Triglycerides yield more energy per gram than carbs because they have more a. C–H bonds b. C–O bonds c. P–O bonds d. N–H bonds Answer: a 47. Cholesterol is integral to a. Mitochondrial matrix b. Cell membranes c. Actin filaments d. RNA formation Answer: b 48. An amphipathic lipid in membranes is a. Triglyceride b. Phospholipid c. Cholesterol exclusively d. Wax Answer: b 49. The first product of fatty acid β-oxidation is a. Acetyl-CoA b. Malonyl-CoA c. Propionyl-CoA d. Succinyl-CoA Answer: a 50. Glycolysis occurs in a. Mitochondrial matrix b. Cytosol c. Nucleus d. Endoplasmic reticulum Answer: b 51. In the hexose monophosphate shunt NADPH is produced for a. Oxidative phosphorylation b. Biosynthetic reductions c. ATP synthesis d. Ribosome assembly Answer: b 52. The Cori cycle links muscle and liver by transporting a. Lactate b. Urea c. Ammonia d. FAs Answer: a 53. The rate-limiting enzyme of cholesterol synthesis is a. HMG-CoA reductase b. Lipase c. ATP–citrate lyase d. Cholesterol esterase Answer: a 54. Essential fatty acids include a. Oleic acid only b. Linoleic and α-linolenic acids c. Palmitic acid d. Stearic acid Answer: b 55. The α-helix is an example of protein a. Primary structure b. Secondary structure c. Tertiary structure d. Quaternary structure Answer: b 56. An example of a conjugated protein is a. Albumin b. Hemoglobin (heme + globin) c. Collagen d. Insulin Answer: b 57. Denaturation breaks a. Peptide bonds b. Disulfide bridges, H-bonds, ionic bonds c. Glycosidic bonds d. Phosphodiester bonds Answer: b 58. Enzyme units are often expressed as a. mg/dL b. μmol product/min c. g/L d. molarity Answer: b 59. Km in Michaelis–Menten kinetics is the substrate concentration at half-maximal a. Reaction velocity b. Enzyme concentration c. Inhibitor concentration d. pH Answer: a 60. Allosteric enzymes differ from Michaelis–Menten enzymes by having a. Single active site b. Multiple subunits and regulatory sites c. No sensitivity to effectors d. Only competitive inhibition Answer: b 61. Competitive inhibitors bind the active site and increase apparent a. Vmax only b. Km only c. Both Vmax and Km d. Neither Vmax nor Km Answer: b 62. In noncompetitive inhibition, Vmax a. Increases b. Decreases c. Unchanged d. Becomes zero Answer: b 63. Vitamin B2 (riboflavin) is converted into a. NADH b. FAD, FMN c. CoA d. Thiamine pyrophosphate Answer: b 64. Pellagra’s dermatitis, diarrhea, dementia, death triad is due to B3 deficiency, also called a. Beriberi b. Scurvy c. Pellagra d. Rickets Answer: c 65. The anti-haemorrhagic vitamin is a. A b. C c. D d. K Answer: d 66. Vitamin E protects membranes by trapping a. Hydroxides b. Peroxyl radicals c. CO2 d. H2O Answer: b 67. Thiamine deficiency causes a. Megaloblastic anemia b. Beriberi, Wernicke–Korsakoff c. Rickets d. Scurvy Answer: b 68. The cofactor TPP is derived from a. Niacin b. Thiamine c. Riboflavin d. Biotin Answer: b 69. Pernicious anemia is treated with a. Oral iron b. Intramuscular B12 c. Vitamin D d. Niacin Answer: b 70. A quick test for vitamin C deficiency is a. Serum folate b. Urine chromatography c. Serum ascorbate level d. Skin biopsy Answer: c 71. DNA double helix rotations per turn ≈ a. 5 b. 10 c. 20 d. 30 Answer: b 72. In recombinant DNA work, vectors carry foreign DNA into a. Animals only b. Host cells (bacteria, yeast) c. Soil d. DNA polymerase Answer: b 73. Restriction enzymes cut DNA at a. Specific palindromic sequences b. Random sites c. Promoters d. Ribonucleotides Answer: a 74. DNA ligase joins a. RNA strands b. Okazaki fragments, vector + insert c. Fatty acids d. Proteins Answer: b 75. Reverse transcriptase synthesizes cDNA from a. Genomic DNA b. mRNA c. tRNA d. rRNA Answer: b 76. A genomic library contains a. All mRNAs of a cell b. All genomic DNA fragments c. Only exons d. Only plasmid DNA Answer: b 77. cDNA libraries lack a. Introns b. Exons c. Promoters d. Poly-A tails Answer: a 78. PCR amplifies DNA using a. DNA ligase b. Taq polymerase c. Reverse transcriptase d. RNase Answer: b 79. Acid–base balance is regulated by buffers, lungs, kidneys. Lungs adjust a. Urine pH b. CO2 exhalation c. Sodium retention d. Bicarbonate synthesis Answer: b 80. A normal arterial pH is about a. 6.8 b. 7.4 c. 7.8 d. 8.2 Answer: b 81. Respiratory acidosis shows a. Low CO2, high pH b. High CO2, low pH c. High HCO3–, high pH d. Low HCO3–, high pH Answer: b 82. Metabolic alkalosis is characterized by a. ↓ HCO3–, ↓ pH b. ↑ HCO3–, ↑ pH c. ↑ CO2, ↓ pH d. ↓ CO2, ↓ pH Answer: b 83. Major extracellular anion is a. Na+ b. K+ c. Cl– d. Ca2+ Answer: c 84. Hyperkalemia most likely causes a. Muscle weakness, arrhythmias b. Tetany c. Alkalosis d. Polyuria Answer: a 85. Insulin promotes uptake of a. Glucose, K+ into cells b. Calcium only c. Sodium only d. Urea Answer: a 86. ADH increases water reabsorption in a. Proximal tubule b. Collecting duct c. Loop of Henle d. Glomerulus Answer: b 87. Erythropoietin is produced by a. Liver b. Kidney c. Bone marrow d. Pituitary Answer: b 88. Parathyroid hormone raises serum calcium by all EXCEPT a. ↑ bone resorption b. ↑ renal Ca2+ reabsorption c. ↑ intestinal Ca2+ absorption (via active D) d. ↓ calcitriol production Answer: d 89. Calcitonin from thyroid parafollicular cells lowers Ca2+ by a. Inhibiting osteoclasts b. Promoting GI calcium absorption c. Increasing renal reabsorption d. Increasing PTH Answer: a 90. Glucagon’s primary action in liver is to a. Inhibit gluconeogenesis b. Stimulate glycogenolysis, gluconeogenesis c. Convert glycerol to triglyceride d. Increase lipogenesis Answer: b 91. The primary messenger for insulin is a. cAMP b. Ca2+ only c. Glucose d. Cl– Answer: a 92. Steroid hormones act by binding a. Membrane receptor, cAMP b. Intracellular nuclear receptors c. Ion channels d. G-protein i receptors only Answer: b 93. An example of steroid hormone is a. Insulin b. Cortisol c. Glucagon d. Epinephrine Answer: b 94. Thyroid hormones require iodine for synthesis of a. T3, T4 b. A, D c. E only d. B12 Answer: a 95. The average adult needs about ________ mg of sodium per day. a. 1–2 g b. 10–20 mg c. 100–200 mg d. 0.5 mg Answer: a 96. Water makes up about ________ % of total body weight. a. 10 b. 30 c. 60 d. 90 Answer: c 97. Hypernatremia often presents with a. Cellular swelling b. Confusion, irritability, coma c. Tachycardia d. Hypotension only Answer: b 98. Metabolic acidosis compensation via respiration shows a. Decreased ventilation b. Increased ventilation c. No change d. Hypokalemia Answer: b 99. A major intracellular buffer is a. HCO3− b. Hemoglobin c. Phosphate d. Protein Answer: c 100. A key organ for long-term acid–base regulation is the a. Liver b. Kidney c. Lung d. Pancreas Answer: b 101. In glycolysis, the first committed step is catalyzed by: a. Hexokinase b. Phosphofructokinase-1 c. Pyruvate kinase d. Aldolase 102. Fructose-2,6-bisphosphate allosterically activates: a. Hexokinase b. Pyruvate kinase c. Phosphofructokinase-1 d. Fructose-1,6-bisphosphatase 103. In the liver, the “high-Km” hexokinase isoform is called: a. Hexokinase I b. Hexokinase II c. Glucokinase d. Fructokinase 104. The enzyme that produces NADH in the glyceraldehyde-3-phosphate step is: a. Phosphoglycerate kinase b. Glyceraldehyde-3-phosphate dehydrogenase c. Enolase d. Aldolase 105. The net ATP yield of anaerobic glycolysis per glucose is: a. 1 b. 2 c. 4 d. 6 106. Lactate dehydrogenase regenerates NAD+ by converting pyruvate into: a. Acetyl-CoA b. Oxaloacetate c. Lactate d. Alanine 107. The Citric Acid Cycle occurs in the: a. Cytosol b. Mitochondrial matrix c. Nucleus d. Endoplasmic reticulum 108. The rate-limiting enzyme of the TCA cycle is: a. Citrate synthase b. Isocitrate dehydrogenase c. α-Ketoglutarate dehydrogenase d. Succinate dehydrogenase 109. α-Ketoglutarate dehydrogenase requires all EXCEPT: a. TPP (thiamine pyrophosphate) b. FAD c. NAD+ d. Biotin 110. Succinate dehydrogenase is unique because it also participates in: a. Glycolysis b. Electron transport chain c. Urea cycle d. Fatty acid synthesis 111. The major proton pump complexes in ETC are I, III and: a. Complex II b. Complex IV c. Complex V d. Cytochrome c only 112. ATP synthase is also known as: a. Complex III b. Complex IV c. Complex V d. Cytochrome c 113. The P:O ratio approximates the ATP generated per pair of electrons passing to: a. Oxygen b. NADH c. FADH2 d. ADP 114. In oxidative phosphorylation, the chemiosmotic theory was proposed by: a. Warburg b. Krebs c. Mitchell d. Gibbs 115. Fatty acid β-oxidation occurs in the: a. Cytosol b. Mitochondrial matrix c. Peroxisome only d. Nucleus 116. The carnitine shuttle transports fatty acyl groups into mitochondria by: a. Simple diffusion b. Esterifying them to carnitine c. Binding to CoA in cytosol d. Converting to ketone bodies 117. Ketone bodies (acetoacetate, β-hydroxybutyrate) are produced by the: a. Brain b. Liver c. Muscle d. Kidney 118. The major site of gluconeogenesis is the: a. Muscle b. Kidney c. Liver d. Brain 119. Gluconeogenesis bypasses pyruvate kinase by first converting oxaloacetate to: a. Phosphoenolpyruvate b. Malate c. Citrate d. Acetyl-CoA 120. The Cori cycle shuttles lactate from muscle to the liver, converting it back to: a. Pyruvate b. Glucose c. Ketone bodies d. Alanine 121. The hexose monophosphate shunt provides NADPH for: a. Oxidative phosphorylation b. Fatty acid synthesis, detoxification c. Amino acid catabolism d. Glycogen breakdown 122. Glucose-6-phosphate dehydrogenase deficiency causes: a. Megaloblastic anemia b. Hemolytic anemia under oxidative stress c. Hypoglycemia d. Rickets 123. Glycogen phosphorylase deficiency in muscle leads to: a. Pompe disease b. McArdle disease c. von Gierke disease d. Hers disease 124. Glycogen synthase is activated by: a. cAMP b. Glucose-6-phosphate c. Glucagon d. Epinephrine 125. Urea is synthesized primarily in the: a. Kidney b. Liver c. Muscle d. Pancreas 126. The first nitrogen in urea originates from ammonia; the second from: a. Glutamate b. Aspartate c. Alanine d. Carbamoyl phosphate 127. The vitamin derivative required in transamination is: a. NAD+ b. Biotin c. Pyridoxal phosphate (B6) d. Thiamine pyrophosphate 128. Phenylketonuria arises from deficiency of: a. Tyrosine hydroxylase b. Phenylalanine hydroxylase c. Homogentisate oxidase d. Branched‐chain α-keto acid dehydrogenase 129. Maple syrup urine disease is due to defect in: a. Urea cycle b. Phenylalanine metabolism c. Branched-chain α-keto acid dehydrogenase d. Homogentisate oxidase 130. In Alopecia areata, the autoimmune attack primarily targets: a. Keratinocytes b. Melanocytes c. Hair follicles d. Sebaceous glands 131. Lipoprotein lipase is activated by: a. Insulin b. Glucagon c. Epinephrine d. Thyroxine 132. The rate-limiting enzyme of cholesterol biosynthesis is: a. Acetyl-CoA carboxylase b. HMG-CoA reductase c. Squalene synthase d. Cholesterol oxidase 133. Statins lower cholesterol by inhibiting: a. Pancreatic lipase b. HMG-CoA reductase c. LDL receptor d. CETP 134. Familial hypercholesterolemia is due to lack of functional: a. Lipoprotein lipase b. HMG-CoA reductase c. LDL receptors d. HDL receptors 135. HDL mediates reverse cholesterol transport via: a. CETP b. LCAT c. Apolipoprotein B d. ATGL 136. ApoB-100 is essential for: a. VLDL assembly b. HDL maturation c. Lipoprotein lipase activity d. CETP exchange 137. Beta-oxidation of an odd-chain fatty acid yields propionyl-CoA which enters TCA as: a. Acetyl-CoA b. Succinyl-CoA c. Pyruvate d. Oxaloacetate 138. Ketone bodies can be used for fuel by all EXCEPT: a. Liver b. Brain c. Muscle d. Kidney 139. The cori cycle protects muscle from lactic acidosis by: a. Exporting glucose b. Converting lactate to glucose in liver c. Using lactate as fuel in muscle d. Converting lactate to alanine 140. The palmitate shuttle for FA synthesis exports citrate from mitochondria in exchange for: a. Oxaloacetate b. Malate c. Acetate d. Pyruvate 141. Acetyl-CoA carboxylase is allosterically activated by: a. Palmitoyl-CoA b. Citrate c. AMP d. Glucagon 142. The glyoxylate cycle occurs in: a. Bacteria only b. Plants and bacteria c. Animals d. Fungi only 143. The primary amino acid for nitrogen transport from muscle to liver is: a. Glutamine b. Alanine c. Aspartate d. Serine 144. Ammonia is detoxified in the brain mainly by: a. Urea cycle b. Glutamine synthetase c. Glutamate dehydrogenase d. Carbamoyl phosphate synthetase I 145. Carbamoyl phosphate synthetase II acts in: a. Urea cycle b. Pyrimidine synthesis (cytosol) c. Purine synthesis d. Fatty acid oxidation 146. The pyrimidine ring is built on the ribose-5-phosphate backbone in: a. Purine synthesis b. Pyrimidine synthesis c. Glycolysis d. Pentose phosphate path 147. De novo purine synthesis is inhibited by: a. AMP, GMP feedback b. UTP feedback c. CTP feedback d. IMP depletion 148. Xanthine oxidase inhibitors (allopurinol) treat gout by blocking: a. Purine synthesis b. Uric acid formation c. Urea cycle d. Pyrimidine salvage 149. DNA replication in eukaryotes requires a short RNA primer made by: a. DNA polymerase I b. Primase c. Ligase d. Helicase 150. Telomerase maintains chromosome ends by adding repeats using: a. DNA b. RNA template c. Reverse transcriptase activity d. DNA ligase 151. Cyclin D binds CDK4 to promote progression through: a. G1/S checkpoint b. G2/M checkpoint c. S phase progression d. Metaphase 152. p53 induces expression of p21, which inhibits: a. Cyclin E–CDK2 b. Cyclin B–CDK1 c. Cyclin A–CDK2 d. Cyclin D–CDK4 153. The intrinsic apoptotic pathway is initiated by: a. Death receptor activation b. DNA damage and mitochondrial cytochrome c release c. Granzyme B from cytotoxic T cells d. TNF-α binding 154. Bcl-2 family proteins regulate apoptosis by controlling: a. Caspase activation b. Mitochondrial membrane permeability c. DNA fragmentation d. Death receptor clustering 155. In receptor tyrosine kinase signaling, adaptor protein Grb2 binds to: a. SH2 domain on phosphorylated RTK b. GTP-bound Ras c. PI3K d. JAK 156. The MAPK cascade includes Ras, Raf, MEK and: a. ERK b. PI3K c. AKT d. JNK 157. G-protein-coupled receptors activate Gα subunits by exchanging GDP for: a. ATP b. cGMP c. GTP d. GDP 158. Adenylyl cyclase catalyzes conversion of ATP to: a. cAMP b. ATP c. cGMP d. GTP 159. Phospholipase C cleaves PIP2 into DAG and: a. IP3 b. cAMP c. PI3P d. PIP3 160. IP3 stimulates release of Ca2+ from: a. Endoplasmic reticulum b. Golgi apparatus c. Mitochondria d. Lysosomes 161. The first line of defense in innate immunity includes: a. Natural killer cells b. Antibodies c. Complement proteins d. Memory T cells 162. Toll-like receptors recognize pathogen-associated molecular patterns and are located on: a. Nuclear membrane b. Cell surface or endosomal membranes c. Mitochondrial membrane d. Cytosol only 163. Neutrophils kill bacteria primarily by: a. Phagocytosis and respiratory burst b. Antibody production c. Complement activation d. Cytotoxic granule release 164. Presentation of endogenous antigens occurs via MHC class: a. I b. II c. III d. IV 165. CD8+ T cells recognize peptides bound to: a. MHC I b. MHC II c. MHC III d. MHC IV 166. B cells undergo somatic hypermutation and class switching in the: a. Bone marrow b. Thymus c. Germinal centers of lymph nodes d. Spleen white pulp 167. IgG is the only immunoglobulin that: a. Crosses the placenta b. Has a pentameric structure c. Exists as a dimer d. Activates mast cells 168. Complement component C3b is an opsonin that facilitates: a. Phagocytosis b. Membrane attack complex formation c. Chemotaxis d. B cell activation 169. Toll-like receptor 4 recognizes: a. Lipopolysaccharide b. Flagellin c. Double-stranded RNA d. Unmethylated CpG DNA 170. Natural killer cells detect infected cells by binding those with low levels of: a. MHC I b. MHC II c. IgG d. CD4 171. Polymerase chain reaction requires all EXCEPT: a. DNA template b. DNA primers c. dNTPs d. Topoisomerase 172. In Southern blotting, DNA fragments are separated by: a. Agarose gel electrophoresis b. SDS-PAGE c. Two-dimensional gel d. Isoelectric focusing 173. Northern blotting is used to detect: a. RNA b. DNA c. Protein d. Lipids 174. Western blotting detects specific proteins using: a. Antibodies b. Probes c. Restriction enzymes d. Radiolabeled nucleotides 175. CRISPR-Cas9 genome editing uses guide RNA and: a. Cas9 nuclease b. dCas9 inactive form c. RNA polymerase d. Reverse transcriptase |
176. Microarrays analyze gene expression by measuring:
a. mRNA hybridization to probes on a chip b. Protein levels by mass spectrometry c. DNA methylation only d. Chromatin structure 177. A reporter gene assay often uses luciferase to monitor: a. Promoter activity b. Protein–protein interactions c. RNA splicing d. DNA replication 178. In flow cytometry, forward scatter correlates with: a. Cell size b. Granularity c. Fluorescence intensity d. Cell viability 179. FACS sorts cells based on: a. Light scattering and fluorescence b. Electrical impedance only c. Magnetic beads d. Density gradient 180. DNA sequencing by the Sanger method uses: a. Dideoxynucleotides b. Reverse transcriptase c. RNA polymerase d. Restriction enzymes 181. The dose at which 50% of subjects exhibit a response is: a. EC50 b. ED50 c. TD50 d. LD50 182. A noncompetitive antagonist: a. Decreases Vmax without affecting Km b. Increases Km without affecting Vmax c. Decreases both Km and Vmax d. Has no effect on Vmax 183. The volume of distribution (Vd) is the ratio of drug amount to: a. Plasma concentration b. Urine concentration c. Tissue binding d. Clearance 184. Drug clearance (Cl) is calculated by: a. Rate of elimination / plasma concentration b. Dose / AUC c. Vd / half-life d. Km / Vmax 185. Phase I drug metabolism primarily involves: a. Oxidation, reduction, hydrolysis b. Conjugation c. Excretion unchanged d. Glycosylation 186. Cytochrome P450 enzymes are located mainly in the: a. Liver endoplasmic reticulum b. Mitochondrial matrix c. Cytosol d. Golgi apparatus 187. The half-life (t1/2) of a drug depends on Vd and: a. Clearance b. Bioavailability c. Absorption rate d. Protein binding 188. Agonist efficacy refers to: a. Maximum response achievable b. Affinity for receptor c. Rate of dissociation d. Volume of distribution 189. Binding of T3 and T4 to nuclear receptors modulates: a. Gene transcription b. Ion channel opening c. cAMP production d. G-protein activation 190. Cortisol exerts its effects by: a. Altering gene transcription via glucocorticoid receptor b. Activating adenylate cyclase c. Binding membrane receptors only d. Inhibiting JAK-STAT pathway 191. The primary thyroid hormone produced by the thyroid gland is: a. T4 (thyroxine) b. T3 (triiodothyronine) c. rT3 (reverse T3) d. Calcitonin 192. Parathyroid hormone increases serum calcium by: a. Increasing bone resorption b. Increasing urinary calcium excretion c. Decreasing vitamin D activation d. Inhibiting osteoclasts 193. Insulin stimulates glucose uptake in muscle by translocating: a. GLUT4 transporters to the cell surface b. GLUT2 to the membrane c. SGLT1 to the cell surface d. GLUT1 to the membrane 194. Glucagon acts through a Gs-coupled receptor to increase: a. cAMP b. IP3 c. DAG d. Calcium 195. Growth hormone release is stimulated by: a. GHRH and ghrelin b. Somatostatin c. IGF-1 feedback d. Cortisol 196. Prolactin release is inhibited by: a. Dopamine b. Oxytocin c. TRH d. CRH 197. ADH (vasopressin) acts on the kidney’s collecting duct via: a. V2 receptors, increasing water reabsorption b. V1 receptors, increasing sodium reabsorption c. V2 receptors, decreasing water reabsorption d. V1 receptors, increasing potassium secretion 198. The renin-angiotensin-aldosterone system is activated by: a. Low renal perfusion pressure b. High sodium delivery c. Increased atrial stretch d. High blood pressure 199. Aldosterone increases sodium reabsorption and potassium secretion in: a. Distal tubule and collecting duct b. Proximal tubule c. Loop of Henle d. Glomerulus 200. Erythropoietin is primarily produced by cells in the: a. Renal interstitium of peritubular fibroblasts b. Liver Kupffer cells c. Bone marrow stromal cells d. Spleen macrophages
201. The resting membrane potential of a typical neuron is approximately: a. –90 mV b. –70 mV c. –55 mV d. +30 mV Answer: b 202. The upstroke (phase 0) of a neuronal action potential is primarily due to: a. Na+ influx b. K+ efflux c. Ca2+ influx d. Cl– influx Answer: a 203. The absolute refractory period results from inactivation of: a. K+ channels b. Na+ channels c. Ca2+ channels d. Cl– channels Answer: b 204. Saltatory conduction occurs at the: a. Nodes of Ranvier b. Neuromuscular junction c. Dendritic spines d. Myelin sheath internodes Answer: a 205. At the neuromuscular junction, acetylcholine is degraded by: a. Acetylcholinesterase b. Choline acetyltransferase c. Butyrylcholinesterase d. Monoamine oxidase Answer: a 206. Smooth muscle contraction is regulated by: a. Ca2+–calmodulin activation of myosin light-chain kinase b. Troponin binding Ca2+ c. Ryanodine receptor activation d. Dihydropyridine receptor Answer: a 207. The plateau phase (phase 2) of the cardiac action potential is due to: a. Ca2+ influx b. K+ efflux c. Na+ influx d. Cl– influx Answer: a 208. The Frank–Starling law states that stroke volume increases with: a. Increased preload b. Increased afterload c. Increased heart rate d. Increased contractility Answer: a 209. The primary pacemaker of the heart is located in the: a. Sinoatrial (SA) node b. Atrioventricular (AV) node c. Purkinje fibers d. Bundle of His Answer: a 210. In blood, the majority of CO2 is transported as: a. Bicarbonate (HCO3–) b. Dissolved CO2 c. Carbaminohemoglobin d. Carbon monoxide complex Answer: a 211. A rightward shift of the oxyhemoglobin dissociation curve occurs with: a. Increased 2,3-BPG b. Increased pH c. Decreased temperature d. Decreased CO2 Answer: a 212. The primary muscle of quiet inspiration is the: a. Diaphragm b. Internal intercostals c. External intercostals d. Rectus abdominis Answer: a 213. The glomerular filtration barrier includes all EXCEPT: a. Fenestrated endothelium b. Basement membrane c. Podocyte foot processes d. Parietal layer of Bowman’s capsule Answer: d 214. The majority of filtered glucose is reabsorbed in the: a. Proximal convoluted tubule b. Loop of Henle c. Distal convoluted tubule d. Collecting duct Answer: a 215. Aldosterone increases sodium reabsorption primarily by upregulating: a. Epithelial sodium channels (ENaC) b. Na+–K+–2Cl– cotransporter (NKCC) c. Na+/K+ ATPase d. Aquaporin-2 channels Answer: a 216. Gastric parietal cells secrete hydrogen ions via: a. H+/K+ ATPase b. Na+/H+ exchanger c. Carbonic anhydrase d. K+/Cl– cotransporter Answer: a 217. Gastric chief cells secrete: a. Pepsinogen b. Hydrochloric acid c. Mucus d. Intrinsic factor Answer: a 218. Bile acids are synthesized from: a. Cholesterol b. Triglycerides c. Phospholipids d. Amino acids Answer: a 219. Pancreatic exocrine secretion is stimulated by: a. Cholecystokinin (CCK) and secretin b. Gastrin c. Motilin d. Substance P Answer: a 220. Hepatic portal vein blood is: a. Nutrient-rich and oxygen-poor b. Oxygen-rich and nutrient-poor c. Nutrient-rich and oxygen-rich d. Nutrient-poor and oxygen-poor Answer: a 221. The largest lymphoid organ in the body is the: a. Spleen b. Thymus c. Lymph node d. Tonsil Answer: a 222. The intrinsic coagulation pathway is initiated by: a. Contact activation of factor XII b. Tissue factor exposure c. Platelet adhesion d. Fibrinogen conversion Answer: a 223. Vitamin K is required for γ-carboxylation of: a. Prothrombin (factor II) and factors VII, IX, X b. Fibrinogen c. Factor XI d. Factor V Answer: a 224. Aplastic anemia is characterized by: a. Pancytopenia with hypocellular bone marrow b. Hemolysis c. Microcytic RBCs d. Megaloblastic changes Answer: a 225. Thalassemias result from mutations in: a. Globin chains of hemoglobin b. Porphyrin synthesis c. Heme iron insertion d. Erythropoietin receptor Answer: a 226. Sickle cell anemia is caused by a: a. Point mutation in the β-globin gene b. Frameshift insertion in α-globin c. Nonsense mutation in γ-globin d. Deletion of δ-globin Answer: a 227. The osmotic fragility test is positive in: a. Hereditary spherocytosis b. G6PD deficiency c. Immune hemolytic anemia d. Sickle cell disease Answer: a 228. Eosinophils are primarily involved in: a. Parasitic infections and allergic reactions b. Bacterial phagocytosis c. Antiviral defense d. Clot stabilization Answer: a 229. The humoral immune response is mediated by: a. B cells and antibodies b. T cells and macrophages c. Natural killer cells d. Complement only Answer: a 230. Natural killer cells target cells lacking: a. MHC I b. Antibody coating c. Complement proteins d. T-cell receptors Answer: a 231. Bacterial cell wall peptidoglycan is composed of: a. N-acetylglucosamine and N-acetylmuramic acid b. Lipopolysaccharide c. Teichoic acids only d. Phospholipids Answer: a 232. Gram-positive bacteria are characterized by: a. Thick peptidoglycan layer b. Outer membrane c. Lipopolysaccharide-rich outer layer d. Periplasmic space only Answer: a 233. β-Lactam antibiotics inhibit: a. Transpeptidase (DD-transpeptidase) b. DNA gyrase c. 30S ribosomal subunit d. Dihydrofolate reductase Answer: a 234. Chloramphenicol binds to the: a. 50S ribosomal subunit b. 30S ribosomal subunit c. DNA-dependent RNA polymerase d. Peptidoglycan synthesis enzymes Answer: a 235. Mycobacterium tuberculosis is classically: a. Acid-fast bacillus b. Gram-negative cocci c. Spore-forming rod d. Catalase-negative Answer: a 236. HIV primarily infects: a. CD4+ T cells b. B cells c. Neutrophils d. Erythrocytes Answer: a 237. Influenza virus uncoating is triggered by: a. Low pH in the endosome b. Cytosolic proteases c. Neutral pH in the ER d. Capsid phosphorylation Answer: a 238. Antigenic shift in influenza results from: a. Reassortment of segmented genome b. Point mutations in hemagglutinin c. Recombination with bacterial DNA d. Deletion of neuraminidase gene Answer: a 239. PCR amplification requires: a. Thermal cycling b. Constant temperature c. UV light activation d. Magnetic beads Answer: a 240. Southern blotting detects: a. Specific DNA sequences b. Specific RNA sequences c. Proteins d. Lipids Answer: a 241. Mendel’s first law is the law of: a. Segregation b. Independent assortment c. Dominance d. Linkage Answer: a 242. Hardy–Weinberg equilibrium requires all EXCEPT: a. No selection b. Large population c. Non-random mating d. No mutation Answer: c 243. Trisomy 21 (Down syndrome) usually arises from nondisjunction of: a. Chromosome 21 b. Chromosome 18 c. Chromosome X d. Chromosome 13 Answer: a 244. Epigenetic gene silencing often involves: a. DNA methylation b. Point mutation c. Chromosomal translocation d. RNA splicing Answer: a 245. Tumor suppressor genes follow: a. Knudson’s two-hit hypothesis b. Single-hit activation c. Oncogene activation pattern d. Haploinsufficiency only Answer: a 246. Oncogenes typically arise via: a. Gain-of-function mutations b. Loss-of-function mutations c. Deletion of both alleles d. Enhanced DNA repair Answer: a 247. BRCA1 mutations increase the risk of: a. Breast and ovarian cancer b. Prostate cancer c. Lung cancer d. Melanoma Answer: a 248. Carcinomas originate from: a. Epithelial cells b. Connective tissue c. Lymphoid tissue d. Nervous tissue Answer: a 249. Sarcomas arise from: a. Mesenchymal (connective) tissue b. Epithelial tissue c. Lymphoid tissue d. Neural tissue Answer: a 250. Cancer staging commonly uses the: a. TNM system b. Gleason score c. Apgar score d. Child–Pugh score Answer: a
251. Atrial natriuretic peptide exerts its effects via which second messenger? a. cAMP b. cGMP c. IP3 d. DAG Answer: b 252. Cardiac output is defined as: a. Stroke volume × Heart rate b. Peripheral vascular resistance × Mean arterial pressure c. End-diastolic volume – End-systolic volume d. Systemic vascular resistance × Blood pressure Answer: a 253. The area enclosed by the left ventricular pressure-volume loop represents: a. Stroke volume b. Stroke work c. Ejection fraction d. End-diastolic volume Answer: b 254. Hepatic stellate (Ito) cells primarily store: a. Glycogen b. Vitamin A c. Bilirubin d. Ferritin Answer: b 255. Kupffer cells are resident macrophages in the: a. Hepatic sinusoids b. Portal tract stroma c. Bile canaliculi d. Central vein Answer: a 256. Proximal convoluted tubule epithelial cells are characterized histologically by: a. Microvilli brush border b. Squamous flattened cells c. Sparse mitochondria and few microvilli d. Ciliated epithelium Answer: a 257. Alport syndrome is due to mutation in type ___ collagen. a. I b. III c. IV d. V Answer: c 258. Goodpasture syndrome involves autoantibodies against: a. Alveolar and glomerular basement membranes b. Type I collagen c. Desmosomal cadherins d. Podocyte slit-diaphragm proteins Answer: a 259. Membranous nephropathy is characterized by subepithelial: a. Immune complex deposits b. Electron-lucent “spikes” on BM c. Podocyte foot process effacement only d. Crescent formation Answer: a 260. Minimal change disease features diffuse podocyte: a. Foot process effacement b. Basement membrane thickening c. Subendothelial immune deposits d. Mesangial matrix expansion Answer: a 261. Diabetic nephropathy often shows nodular glomerulosclerosis known as: a. Kimmelstiel–Wilson nodules b. Mallory bodies c. Councilman bodies d. Negri bodies Answer: a 262. WAGR syndrome (Wilms tumor, Aniridia, GU malformation, mental Retardation) is due to deletion of the ___ gene on chromosome 11. a. WT1 b. NF1 c. RB1 d. TP53 Answer: a 263. The liability threshold model explains inheritance of: a. Multifactorial quantitative traits b. Mendelian single-gene disorders c. Chromosomal nondisjunction syndromes d. X-linked recessive diseases Answer: a 264. Penetrance refers to the proportion of individuals with a genotype who: a. Express the associated phenotype b. Show variable severity of disease c. Carry de novo mutations d. Have gene dosage effects Answer: a 265. Expressivity describes the: a. Degree of phenotypic variation among individuals with the same genotype b. Proportion of affected family members c. Frequency of new mutations d. Inheritance pattern of a gene Answer: a 266. Pleiotropy occurs when one gene: a. Influences multiple distinct phenotypic traits b. Is located on multiple chromosomes c. Controls a single trait only d. Has no phenotypic effect Answer: a 267. Nondisjunction during meiosis I yields two gametes with: a. n+1 and two with n−1 b. All with n c. One with 2n and three with n d. One with n and three with n+1 Answer: a 268. A Robertsonian translocation involves fusion of: a. Two acrocentric chromosomes at the centromere b. Two metacentric chromosomes c. The X and Y chromosomes d. Chromosome arms without centromeres Answer: a 269. Fluorescence in situ hybridization (FISH) uses: a. Fluorescent DNA probes to detect specific chromosomal sequences b. Radioactive probes in a Southern blot c. Antibody probes in a Western blot d. DNA polymerase in PCR amplification Answer: a 270. Sanger DNA sequencing relies on incorporation of: a. Dideoxynucleotides b. Standard deoxynucleotides c. RNA nucleotides d. DNA ligase Answer: a 271. Next-generation sequencing differs from Sanger sequencing by: a. Massive parallelization of DNA reads b. Using only dideoxynucleotides c. Requiring bacterial cloning of templates d. Exclusively sequencing RNA Answer: a 272. Adenoviral vectors used in gene therapy: a. Remain episomal and do not integrate b. Integrate into the host genome c. Have >100 kb packaging capacity d. Elicit no immune response Answer: a 273. Retroviral vectors require which enzyme to integrate into host DNA? a. Reverse transcriptase b. DNA polymerase I c. RNA polymerase II d. DNA ligase Answer: a 274. siRNA mediates gene silencing by: a. Degrading complementary mRNA via the RISC complex b. Promoting DNA methylation c. Acetylating histones d. Blocking ribosomal subunits Answer: a 275. DNA methylation in mammals occurs primarily at: a. CpG dinucleotides b. AT-rich regions c. Telomeric repeats d. Histone proteins Answer: a 276. Histone acetylation is generally associated with: a. Transcriptional activation b. DNA methylation c. Chromatin condensation d. Gene silencing Answer: a 277. MicroRNAs (miRNAs) regulate gene expression by: a. Binding to target mRNAs and inhibiting translation b. Enhancing mRNA splicing c. Promoting DNA replication d. Cleaving genomic DNA Answer: a 278. The RAS oncogene encodes a: a. GTP-binding protein (GTPase) b. Tyrosine kinase receptor c. Transcription factor d. Cyclin-dependent kinase Answer: a 279. The p53 tumor suppressor activates transcription of ___ to induce cell cycle arrest. a. p21 b. Cyclin D c. MDM2 d. Telomerase Answer: a 280. Caspase-3, an executioner caspase, primarily: a. Cleaves cellular substrates during apoptosis b. Phosphorylates Bcl-2 c. Activates NF-κB d. Inhibits cytochrome c release Answer: a 281. Autophagy involves formation of: a. Autophagosomes that fuse with lysosomes b. Apoptotic bodies c. Nuclear envelopes d. Death-inducing signaling complexes Answer: a 282. Acute inflammation is characterized predominantly by: a. Neutrophil infiltration b. Lymphocyte proliferation c. Plasma cell accumulation d. Eosinophil predominance Answer: a 283. Chronic inflammation is marked by: a. Macrophages and lymphocytes b. Neutrophils only c. Basophils only d. Eosinophils exclusively Answer: a 284. Granuloma formation requires activated: a. Macrophages (epithelioid histiocytes) b. Fibroblasts only c. Neutrophils exclusively d. Eosinophils only Answer: a 285. Caseous necrosis is classically seen in: a. Tuberculosis b. Wet gangrene c. Fat necrosis d. Fibrinoid necrosis Answer: a 286. Fibrinoid necrosis is characteristic of: a. Immune complex–mediated vasculitis b. Coagulative necrosis c. Liquefactive necrosis d. Fat necrosis Answer: a 287. Liquefactive necrosis is typical of: a. Brain infarction b. Myocardial infarction c. Tuberculous lymph nodes d. Fat tissue Answer: a 288. Coagulative necrosis is usually seen in: a. Myocardial infarction b. Brain infarction c. Abscess formation d. Pancreatitis Answer: a 289. Pancreatic fat necrosis often leads to saponification due to release of: a. Lipases b. Proteases c. Amylases d. Elastases Answer: a 290. Atherosclerotic plaques develop in the: a. Tunica intima of large arteries b. Tunica media of veins c. Capillaries d. Lymphatic vessels Answer: a 291. Hepatic steatosis (fatty change) is characterized by accumulation of: a. Triglycerides in hepatocytes b. Glycogen in stellate cells c. Bilirubin in bile ducts d. Iron in Kupffer cells Answer: a 292. Cirrhosis histologically shows regenerative nodules surrounded by: a. Fibrous septa b. Fatty infiltration c. Hemochromatosis d. Mallory bodies only Answer: a 293. Acute pancreatitis is diagnosed by elevated serum: a. Amylase and lipase b. ALT and AST only c. Alkaline phosphatase d. Creatine kinase Answer: a 294. Chronic pancreatitis is characterized by: a. Irreversible fibrosis and calcifications b. Reversible edema c. Granulomatous inflammation d. Viral inclusion bodies Answer: a 295. Metabolic acidosis is defined by: a. Decreased HCO3– and decreased pH b. Increased HCO3– and pH c. Normal anion gap only d. Elevated PaCO2 only Answer: a 296. The anion gap is calculated as: a. Na+ – (Cl– + HCO3–) b. K+ – (Na+ + HCO3–) c. Cl– – (Na+ + HCO3–) d. Ca2+ – (Cl– + HCO3–) Answer: a 297. Respiratory compensation for metabolic acidosis involves: a. Hyperventilation to lower PaCO2 b. Hypoventilation to raise PaCO2 c. Increased renal H+ excretion only d. Decreased tidal volume Answer: a 298. Metabolic alkalosis can result from: a. Vomiting and diuretic use b. Diarrhea c. Respiratory depression d. Lactic acidosis Answer: a 299. In acute respiratory acidosis, kidneys compensate by: a. Excreting H+ and reabsorbing HCO3– b. Increasing ventilation c. Decreasing renal H+ excretion d. Lowering tubular HCO3– reabsorption Answer: a 300. A mixed acid-base disorder is suspected when: a. Compensation is inadequate for the primary disturbance b. pH remains within normal range c. Compensatory response exactly matches expected d. No primary acid-base disturbance is present Answer: a 301. The movement of water across semipermeable membranes driven by osmotic gradients is known as: a. Diffusion b. Osmosis c. Facilitated diffusion d. Active transport Answer: b 302. Facilitated diffusion requires: a. ATP hydrolysis b. Carrier proteins c. Ion pumps d. Endocytosis Answer: b 303. Primary active transport directly uses energy from: a. ATP hydrolysis b. Electrochemical gradients c. Osmotic pressure d. Phosphorylation by kinases Answer: a 304. Na+/K+ ATPase transports: a. 3 Na+ out and 2 K+ in per ATP b. 2 Na+ out and 3 K+ in per ATP c. 3 Na+ in and 2 K+ out per ATP d. 2 Na+ in and 3 K+ out per ATP Answer: a 305. In receptor-mediated endocytosis, which molecule binds LDL particles for internalization? a. Transferrin b. LDL receptor c. Clathrin d. Caveolin Answer: b 306. Clathrin-coated pits are involved in: a. Pinocytosis b. Receptor-mediated endocytosis c. Phagocytosis d. Passive diffusion Answer: b 307. Caveolae are flask-shaped invaginations rich in: a. Cholesterol and caveolin b. Clathrin and adaptin c. Actin filaments d. Spectrin Answer: a 308. The classical complement pathway is initiated by: a. Mannose-binding lectin b. C-reactive protein binding c. IgG or IgM binding to antigen d. LPS recognition by C1 Answer: c 309. Mannose-binding lectin activates complement via: a. Classical pathway b. Alternative pathway c. Lectin pathway d. Terminal pathway Answer: c 310. The kinin system generates bradykinin, leading to: a. Vasoconstriction b. Vasodilation and pain c. Platelet aggregation d. Complement activation Answer: b 311. Bradykinin is degraded by: a. ACE b. Renin c. Kallikrein d. Plasmin Answer: a 312. Prostaglandin E2 contributes to: a. Gastric mucosal protection b. Platelet aggregation c. Vasoconstriction d. Bronchospasm Answer: a 313. Cyclooxygenase-2 (COX-2) selective inhibitors reduce: a. GI ulceration b. Renal blood flow c. Platelet aggregation d. Fever Answer: a 314. In the JAK-STAT signaling pathway, cytokine binding leads to: a. GTPase activation b. STAT phosphorylation and dimerization c. PI3K activation d. MAPK inhibition Answer: b 315. Toll-like receptor 9 recognizes: a. dsRNA b. LPS c. CpG DNA d. Flagellin Answer: c 316. Dendritic cells present antigen to naïve T cells in: a. Spleen only b. Lymph nodes c. Bone marrow d. Thymus Answer: b 317. Regulatory T cells express: a. CD8 and perforin b. CD4 and FoxP3 c. CD16 and CD56 d. CD19 and CD20 Answer: b 318. Memory B cells differ from plasma cells by: a. High antibody secretion b. Long lifespan and quick activation c. MHC II downregulation d. No surface Ig Answer: b 319. Isoenzymes of creatine kinase include CK-MB, which is a marker for: a. Liver disease b. Myocardial infarction c. Muscular dystrophy d. Brain injury Answer: b 320. Troponin I is more specific than CK-MB for: a. Skeletal muscle injury b. Acute myocardial infarction c. Liver necrosis d. Pulmonary embolism Answer: b 321. Brain natriuretic peptide (BNP) levels rise in: a. Acute pancreatitis b. Heart failure c. Hypertension d. Hypovolemia Answer: b 322. In heart failure, increased preload leads to: a. Decreased end-diastolic volume b. Increased stroke volume via Frank–Starling c. Decreased contractility d. Decreased ejection fraction Answer: b 323. Loop diuretics act by inhibiting NKCC in: a. Proximal tubule b. Descending limb c. Thick ascending limb of the loop of Henle d. Collecting duct Answer: c 324. Thiazide diuretics inhibit NCC in the: a. Proximal tubule b. Distal convoluted tubule c. Loop of Henle d. Collecting duct Answer: b 325. Aldosterone antagonists such as spironolactone block: a. ENaC directly b. Mineralocorticoid receptor c. Na+/K+ ATPase d. 11β-HSD2 enzyme Answer: b 326. Acetazolamide induces metabolic acidosis by: a. Inhibiting carbonic anhydrase in the PCT b. Blocking Na+/K+ ATPase c. Increasing aldosterone secretion d. Enhancing bicarbonate reabsorption Answer: a 327. Most bicarbonate reabsorption occurs in the: a. Proximal convoluted tubule b. Loop of Henle c. Distal tubule d. Collecting duct Answer: a 328. In osteoclasts, bone resorption is mediated by: a. Osteoprotegerin b. RANKL–RANK interaction c. IGF-1 signaling d. Osteocalcin Answer: b 329. Vitamin D increases calcium absorption in the intestine by: a. Upregulating calbindin b. Inhibiting PTH c. Blocking vitamin K d. Binding osteoclast receptors Answer: a 330. PTH secretion is inhibited by: a. Hypocalcemia b. Hyperphosphatemia c. Hypercalcemia d. Low magnesium Answer: c 331. In type I hypersensitivity, sensitization requires: a. IgG binding b. Initial allergen exposure and IgE production c. Complement activation d. T-cell mediated cytotoxicity Answer: b 332. Mast cell degranulation releases: a. Histamine and tryptase b. Perforin and granzyme c. Antibodies d. Cytokines only Answer: a 333. Anaphylaxis is treated with: a. Intravenous fluids only b. Epinephrine c. Antihistamines alone d. Corticosteroids alone Answer: b 334. TNF-α blockers such as infliximab are used in: a. Type 1 diabetes b. Rheumatoid arthritis c. Asthma d. Hypertension Answer: b 335. IL-1 receptor antagonist anakinra is effective in: a. Gout b. Rheumatoid arthritis c. Multiple sclerosis d. Crohn’s disease Answer: b 336. Monoclonal antibody rituximab targets: a. CD20 on B cells b. TNF-α c. IL-2 receptor d. PD-1 on T cells Answer: a 337. PD-1 inhibitors like pembrolizumab block: a. T-cell checkpoint inhibition b. B-cell receptor signaling c. Complement activation d. Cytokine synthesis Answer: a 338. CAR-T cell therapy involves: a. Genetically engineered T cells targeting tumor antigens b. Checkpoint blockade c. Cytokine infusion d. Stem cell transplant Answer: a 339. In electrophoresis, DNA migrates toward the: a. Anode (positive electrode) b. Cathode (negative electrode) c. Center of the gel d. Whichever well has more ethidium bromide Answer: a 340. Restriction fragment length polymorphism (RFLP) analysis detects: a. Differences in DNA fragment size after enzyme digestion b. Gene expression levels c. Protein isoforms d. mRNA splicing variants Answer: a 341. Southern blotting requires transfer of DNA from gel to: a. Nitrocellulose or nylon membrane b. PVDF membrane c. Agarose membrane d. SDS-PAGE gel Answer: a 342. Western blotting transfer is typically to: a. PVDF or nitrocellulose membrane b. Nylon membrane c. Silicon wafer d. Agarose gel Answer: a 343. Immunohistochemistry detects antigens in tissue using: a. Labeled antibodies b. Radioisotope probes c. DAPI staining d. H&E only Answer: a 344. Flow cytometry can analyze: a. Cell size, granularity, and fluorescence b. Mitochondrial ultrastructure c. Chromosomal karyotype d. Tissue architecture Answer: a 345. Electrophoretic mobility shift assay (EMSA) identifies: a. DNA–protein interactions b. RNA transcript sizes c. Protein–protein interactions d. Carbohydrate structures Answer: a 346. Chromatin immunoprecipitation (ChIP) assays map: a. Protein–DNA binding sites in vivo b. mRNA levels c. DNA methylation patterns only d. Histone sequences Answer: a 347. FISH can detect: a. Chromosomal translocations and gene copy number changes b. Protein phosphorylation c. RNA splicing variants d. Metabolic flux Answer: a 348. Telomerase is active in: a. Germ cells and cancer cells b. Most somatic cells c. Red blood cells d. Platelets Answer: a 349. Heteroplasmy refers to: a. Coexistence of mutated and wild-type mitochondrial DNA in a cell b. Variation in nuclear gene expression c. Multiple alleles at a locus d. X-inactivation patterns Answer: a 350. Uniparental disomy occurs when both homologous chromosomes are inherited from: a. One parent b. Both parents normally c. Different species d. Mitochondrial genome Answer: a |
