NBME CBSE ACTUAL EXAM SCRIPT 2026
COMPREHENSIVE QUESTIONS AND
CORRECT ANSWERS
⩥ G1/S Checkpoint. Answer: Controlled by Rb protein
⩥ G2/M Checkpoint. Answer: Controlled by p53 protein
⩥ p53/p21. Answer: Tumor suppressors
⩥ Cyclins/CDKs. Answer: Regulate progression of the cell cycle
⩥ Rb phosphorylation. Answer: Promotes cell cycle progression
⩥ Bioavailability (F). Answer: Fraction of drug reaching systemic
circulation
⩥ Half-life (t½). Answer: t½ = 0.693 × Vd / CL
⩥ Volume of Distribution (Vd). Answer: Increases for lipophilic drugs
⩥ Clearance (CL). Answer: CL = Rate of elimination / [Drug]
,⩥ Loading Dose (LD). Answer: LD = Cp × Vd / F
⩥ Maintenance Dose (MD). Answer: MD = Cp × CL × τ / F
⩥ Agonists. Answer: Bind and activate receptors
⩥ Antagonists. Answer: Block receptors
⩥ Competitive Antagonists. Answer: Cause a right shift in the dose-
response curve, same maximum effect
⩥ Noncompetitive Antagonists. Answer: Decrease maximum effect of
the agonist
⩥ Efficacy. Answer: Maximum response of a drug, higher is better
⩥ Potency. Answer: Dose needed for a drug to achieve its effect, higher
means lower dose required
⩥ Michaelis-Menten Curve. Answer: Describes the rate of enzymatic
reactions
,⩥ Km. Answer: Concentration of substrate at half of Vmax
⩥ Competitive Inhibitors. Answer: Increase Km, do not affect Vmax
⩥ Noncompetitive Inhibitors. Answer: Decrease Vmax, do not affect
Km
⩥ cAMP (Gs). Answer: Involved in signaling pathways for β1/2, H2,
D1, TSH, PTH, ACTH, FSH, LH
⩥ IP3 (Gq). Answer: Involved in signaling pathways for α1, M1/3, H1,
GnRH, TRH
⩥ Tyrosine Kinase (RTK). Answer: Signaling pathway for Insulin, IGF-
1, FGF
⩥ JAK-STAT Pathway. Answer: Signaling pathway for GH, Prolactin,
EPO, G-CSF
⩥ CD4⁺ T Cells. Answer: Subtypes include TH1, TH2, TH17, and Treg,
each with specific functions in immune response.
⩥ TH1. Answer: Activates macrophages through IL-12 leading to IFN-γ
production.
, ⩥ TH2. Answer: Activates eosinophils and promotes IgE production via
IL-4, IL-5, and IL-13.
⩥ TH17. Answer: Recruits neutrophils through IL-17.
⩥ Treg. Answer: Suppresses immune responses using IL-10 and TGF-β.
⩥ CD8⁺ T Cells. Answer: Responsible for cytotoxic killing via
perforin/granzymes or FasL.
⩥ B Cell Activation. Answer: Requires CD40-CD40L interaction and
IL-4/IL-5 from CD4⁺ T cells.
⩥ Class Switching. Answer: The process where B cells change the class
of antibody they produce, influenced by cytokines.
⩥ IL-4. Answer: Promotes class switching to IgE and IgG.
⩥ IL-5. Answer: Promotes class switching to IgA.
⩥ Antibody Types. Answer: Includes IgM, IgG, IgA, IgE, and IgD, each
with distinct functions.
COMPREHENSIVE QUESTIONS AND
CORRECT ANSWERS
⩥ G1/S Checkpoint. Answer: Controlled by Rb protein
⩥ G2/M Checkpoint. Answer: Controlled by p53 protein
⩥ p53/p21. Answer: Tumor suppressors
⩥ Cyclins/CDKs. Answer: Regulate progression of the cell cycle
⩥ Rb phosphorylation. Answer: Promotes cell cycle progression
⩥ Bioavailability (F). Answer: Fraction of drug reaching systemic
circulation
⩥ Half-life (t½). Answer: t½ = 0.693 × Vd / CL
⩥ Volume of Distribution (Vd). Answer: Increases for lipophilic drugs
⩥ Clearance (CL). Answer: CL = Rate of elimination / [Drug]
,⩥ Loading Dose (LD). Answer: LD = Cp × Vd / F
⩥ Maintenance Dose (MD). Answer: MD = Cp × CL × τ / F
⩥ Agonists. Answer: Bind and activate receptors
⩥ Antagonists. Answer: Block receptors
⩥ Competitive Antagonists. Answer: Cause a right shift in the dose-
response curve, same maximum effect
⩥ Noncompetitive Antagonists. Answer: Decrease maximum effect of
the agonist
⩥ Efficacy. Answer: Maximum response of a drug, higher is better
⩥ Potency. Answer: Dose needed for a drug to achieve its effect, higher
means lower dose required
⩥ Michaelis-Menten Curve. Answer: Describes the rate of enzymatic
reactions
,⩥ Km. Answer: Concentration of substrate at half of Vmax
⩥ Competitive Inhibitors. Answer: Increase Km, do not affect Vmax
⩥ Noncompetitive Inhibitors. Answer: Decrease Vmax, do not affect
Km
⩥ cAMP (Gs). Answer: Involved in signaling pathways for β1/2, H2,
D1, TSH, PTH, ACTH, FSH, LH
⩥ IP3 (Gq). Answer: Involved in signaling pathways for α1, M1/3, H1,
GnRH, TRH
⩥ Tyrosine Kinase (RTK). Answer: Signaling pathway for Insulin, IGF-
1, FGF
⩥ JAK-STAT Pathway. Answer: Signaling pathway for GH, Prolactin,
EPO, G-CSF
⩥ CD4⁺ T Cells. Answer: Subtypes include TH1, TH2, TH17, and Treg,
each with specific functions in immune response.
⩥ TH1. Answer: Activates macrophages through IL-12 leading to IFN-γ
production.
, ⩥ TH2. Answer: Activates eosinophils and promotes IgE production via
IL-4, IL-5, and IL-13.
⩥ TH17. Answer: Recruits neutrophils through IL-17.
⩥ Treg. Answer: Suppresses immune responses using IL-10 and TGF-β.
⩥ CD8⁺ T Cells. Answer: Responsible for cytotoxic killing via
perforin/granzymes or FasL.
⩥ B Cell Activation. Answer: Requires CD40-CD40L interaction and
IL-4/IL-5 from CD4⁺ T cells.
⩥ Class Switching. Answer: The process where B cells change the class
of antibody they produce, influenced by cytokines.
⩥ IL-4. Answer: Promotes class switching to IgE and IgG.
⩥ IL-5. Answer: Promotes class switching to IgA.
⩥ Antibody Types. Answer: Includes IgM, IgG, IgA, IgE, and IgD, each
with distinct functions.
