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
Answer: b
102. Fructose-2,6-bisphosphate allosterically activates:
a. Hexokinase
b. Pyruvate kinase
c. Phosphofructokinase-1
d. Fructose-1,6-bisphosphatase
Answer: c
103. In the liver, the “high-Km” hexokinase isoform is called:
a. Hexokinase I
b. Hexokinase II
c. Glucokinase
d. Fructokinase
Answer: c
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
Answer: b
105. The net ATP yield of anaerobic glycolysis per glucose is:
a. 1
b. 2
c. 4
d. 6
Answer: b
106. Lactate dehydrogenase regenerates NAD+ by converting pyruvate into:
a. Acetyl-CoA
b. Oxaloacetate
c. Lactate
d. Alanine
Answer: c
107. The Citric Acid Cycle occurs in the:
a. Cytosol
b. Mitochondrial matrix
c. Nucleus
d. Endoplasmic reticulum
Answer: b
108. The rate-limiting enzyme of the TCA cycle is:
a. Citrate synthase
b. Isocitrate dehydrogenase
c. α-Ketoglutarate dehydrogenase
d. Succinate dehydrogenase
Answer: b
109. α-Ketoglutarate dehydrogenase requires all EXCEPT:
a. TPP (thiamine pyrophosphate)
b. FAD
c. NAD+
d. Biotin
Answer: d
110. Succinate dehydrogenase is unique because it also participates in:
a. Glycolysis
b. Electron transport chain
c. Urea cycle
d. Fatty acid synthesis
Answer: b
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
Answer: b
112. ATP synthase is also known as:
a. Complex III
b. Complex IV
c. Complex V
d. Cytochrome c
Answer: c
113. The P:O ratio approximates the ATP generated per pair of electrons passing to:
a. Oxygen
b. NADH
c. FADH2
d. ADP
Answer: a
114. In oxidative phosphorylation, the chemiosmotic theory was proposed by:
a. Warburg
b. Krebs
c. Mitchell
d. Gibbs
Answer: c
115. Fatty acid β-oxidation occurs in the:
a. Cytosol
b. Mitochondrial matrix
c. Peroxisome only
d. Nucleus
Answer: b
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
Answer: b
117. Ketone bodies (acetoacetate, β-hydroxybutyrate) are produced by the:
a. Brain
b. Liver
c. Muscle
d. Kidney
Answer: b
118. The major site of gluconeogenesis is the:
a. Muscle
b. Kidney
c. Liver
d. Brain
Answer: c
119. Gluconeogenesis bypasses pyruvate kinase by first converting oxaloacetate to:
a. Phosphoenolpyruvate
b. Malate
c. Citrate
d. Acetyl-CoA
Answer: b
120. The Cori cycle shuttles lactate from muscle to the liver, converting it back to:
a. Pyruvate
b. Glucose
c. Ketone bodies
d. Alanine
Answer: b
121. The hexose monophosphate shunt provides NADPH for:
a. Oxidative phosphorylation
b. Fatty acid synthesis, detoxification
c. Amino acid catabolism
d. Glycogen breakdown
Answer: b
122. Glucose-6-phosphate dehydrogenase deficiency causes:
a. Megaloblastic anemia
b. Hemolytic anemia under oxidative stress
c. Hypoglycemia
d. Rickets
Answer: b
123. Glycogen phosphorylase deficiency in muscle leads to:
a. Pompe disease
b. McArdle disease
c. von Gierke disease
d. Hers disease
Answer: b
124. Glycogen synthase is activated by:
a. cAMP
b. Glucose-6-phosphate
c. Glucagon
d. Epinephrine
Answer: b
125. Urea is synthesized primarily in the:
a. Kidney
b. Liver
c. Muscle
d. Pancreas
Answer: b
126. The first nitrogen in urea originates from ammonia; the second from:
a. Glutamate
b. Aspartate
c. Alanine
d. Carbamoyl phosphate
Answer: b
127. The vitamin derivative required in transamination is:
a. NAD+
b. Biotin
c. Pyridoxal phosphate (B6)
d. Thiamine pyrophosphate
Answer: c
128. Phenylketonuria arises from deficiency of:
a. Tyrosine hydroxylase
b. Phenylalanine hydroxylase
c. Homogentisate oxidase
d. Branched‐chain α-keto acid dehydrogenase
Answer: b
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
Answer: c
130. In Alopecia areata, the autoimmune attack primarily targets:
a. Keratinocytes
b. Melanocytes
c. Hair follicles
d. Sebaceous glands
Answer: c
131. Lipoprotein lipase is activated by:
a. Insulin
b. Glucagon
c. Epinephrine
d. Thyroxine
Answer: a
132. The rate-limiting enzyme of cholesterol biosynthesis is:
a. Acetyl-CoA carboxylase
b. HMG-CoA reductase
c. Squalene synthase
d. Cholesterol oxidase
Answer: b
133. Statins lower cholesterol by inhibiting:
a. Pancreatic lipase
b. HMG-CoA reductase
c. LDL receptor
d. CETP
Answer: b
134. Familial hypercholesterolemia is due to lack of functional:
a. Lipoprotein lipase
b. HMG-CoA reductase
c. LDL receptors
d. HDL receptors
Answer: c
135. HDL mediates reverse cholesterol transport via:
a. CETP
b. LCAT
c. Apolipoprotein B
d. ATGL
Answer: b
136. ApoB-100 is essential for:
a. VLDL assembly
b. HDL maturation
c. Lipoprotein lipase activity
d. CETP exchange
Answer: a
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
Answer: b
138. Ketone bodies can be used for fuel by all EXCEPT:
a. Liver
b. Brain
c. Muscle
d. Kidney
Answer: a
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
Answer: b
140. The palmitate shuttle for FA synthesis exports citrate from mitochondria in exchange for:
a. Oxaloacetate
b. Malate
c. Acetate
d. Pyruvate
Answer: b
141. Acetyl-CoA carboxylase is allosterically activated by:
a. Palmitoyl-CoA
b. Citrate
c. AMP
d. Glucagon
Answer: b
142. The glyoxylate cycle occurs in:
a. Bacteria only
b. Plants and bacteria
c. Animals
d. Fungi only
Answer: b
143. The primary amino acid for nitrogen transport from muscle to liver is:
a. Glutamine
b. Alanine
c. Aspartate
d. Serine
Answer: b
144. Ammonia is detoxified in the brain mainly by:
a. Urea cycle
b. Glutamine synthetase
c. Glutamate dehydrogenase
d. Carbamoyl phosphate synthetase I
Answer: b
145. Carbamoyl phosphate synthetase II acts in:
a. Urea cycle
b. Pyrimidine synthesis (cytosol)
c. Purine synthesis
d. Fatty acid oxidation
Answer: b
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
Answer: b
147. De novo purine synthesis is inhibited by:
a. AMP, GMP feedback
b. UTP feedback
c. CTP feedback
d. IMP depletion
Answer: a
148. Xanthine oxidase inhibitors (allopurinol) treat gout by blocking:
a. Purine synthesis
b. Uric acid formation
c. Urea cycle
d. Pyrimidine salvage
Answer: b
149. DNA replication in eukaryotes requires a short RNA primer made by:
a. DNA polymerase I
b. Primase
c. Ligase
d. Helicase
Answer: b
150. Telomerase maintains chromosome ends by adding repeats using:
a. DNA
b. RNA template
c. Reverse transcriptase activity
d. DNA ligase
Answer: c
151. Cyclin D binds CDK4 to promote progression through:
a. G1/S checkpoint
b. G2/M checkpoint
c. S phase progression
d. Metaphase
Answer: a
152. p53 induces expression of p21, which inhibits:
a. Cyclin E–CDK2
b. Cyclin B–CDK1
c. Cyclin A–CDK2
d. Cyclin D–CDK4
Answer: a
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
Answer: b
154. Bcl-2 family proteins regulate apoptosis by controlling:
a. Caspase activation
b. Mitochondrial membrane permeability
c. DNA fragmentation
d. Death receptor clustering
Answer: b
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
Answer: a
156. The MAPK cascade includes Ras, Raf, MEK and:
a. ERK
b. PI3K
c. AKT
d. JNK
Answer: a
157. G-protein-coupled receptors activate Gα subunits by exchanging GDP for:
a. ATP
b. cGMP
c. GTP
d. GDP
Answer: c
158. Adenylyl cyclase catalyzes conversion of ATP to:
a. cAMP
b. ATP
c. cGMP
d. GTP
Answer: a
159. Phospholipase C cleaves PIP2 into DAG and:
a. IP3
b. cAMP
c. PI3P
d. PIP3
Answer: a
160. IP3 stimulates release of Ca2+ from:
a. Endoplasmic reticulum
b. Golgi apparatus
c. Mitochondria
d. Lysosomes
Answer: a
161. The first line of defense in innate immunity includes:
a. Natural killer cells
b. Antibodies
c. Complement proteins
d. Memory T cells
Answer: c
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
Answer: b
163. Neutrophils kill bacteria primarily by:
a. Phagocytosis and respiratory burst
b. Antibody production
c. Complement activation
d. Cytotoxic granule release
Answer: a
164. Presentation of endogenous antigens occurs via MHC class:
a. I
b. II
c. III
d. IV
Answer: a
165. CD8+ T cells recognize peptides bound to:
a. MHC I
b. MHC II
c. MHC III
d. MHC IV
Answer: a
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
Answer: c
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
Answer: a
168. Complement component C3b is an opsonin that facilitates:
a. Phagocytosis
b. Membrane attack complex formation
c. Chemotaxis
d. B cell activation
Answer: a
169. Toll-like receptor 4 recognizes:
a. Lipopolysaccharide
b. Flagellin
c. Double-stranded RNA
d. Unmethylated CpG DNA
Answer: a
170. Natural killer cells detect infected cells by binding those with low levels of:
a. MHC I
b. MHC II
c. IgG
d. CD4
Answer: a
171. Polymerase chain reaction requires all EXCEPT:
a. DNA template
b. DNA primers
c. dNTPs
d. Topoisomerase
Answer: d
172. In Southern blotting, DNA fragments are separated by:
a. Agarose gel electrophoresis
b. SDS-PAGE
c. Two-dimensional gel
d. Isoelectric focusing
Answer: a
173. Northern blotting is used to detect:
a. RNA
b. DNA
c. Protein
d. Lipids
Answer: a
174. Western blotting detects specific proteins using:
a. Antibodies
b. Probes
c. Restriction enzymes
d. Radiolabeled nucleotides
Answer: a
175. CRISPR-Cas9 genome editing uses guide RNA and:
a. Cas9 nuclease
b. dCas9 inactive form
c. RNA polymerase
d. Reverse transcriptase
Answer: a |
