NBME CBSE REAL EXAM 2026 | 200 Most Tested Questions and
Answers | Complete CBSE Exam for USMLE
Exam
Cell Cycle Phases - __100% correct answer as G1 → S → G2 → M
G1/S Checkpoint - __100% correct answer as Controlled by Rb protein
G2/M Checkpoint - __100% correct answer as Controlled by p53 protein
p53/p21 - __100% correct answer as Tumor suppressors
Cyclins/CDKs - __100% correct answer as Regulate progression of the cell cycle
Rb phosphorylation - __100% correct answer as Promotes cell cycle progression
Bioavailability (F) - __100% correct answer as Fraction of drug reaching systemic
circulation
Half-life (t½) - __100% correct answer as t½ = 0.693 × Vd / CL
Volume of Distribution (Vd) - __100% correct answer as Increases for lipophilic
drugs
Clearance (CL) - __100% correct answer as CL = Rate of elimination / [Drug]
Loading Dose (LD) - __100% correct answer as LD = Cp × Vd / F
Maintenance Dose (MD) - __100% correct answer as MD = Cp × CL × τ / F
Agonists - __100% correct answer as Bind and activate receptors
Antagonists - __100% correct answer as Block receptors
Competitive Antagonists - __100% correct answer as Cause a right shift in the
dose-response curve, same maximum effect
,Noncompetitive Antagonists - __100% correct answer as Decrease maximum
effect of the agonist
Efficacy - __100% correct answer as Maximum response of a drug, higher is
better
Potency - __100% correct answer as Dose needed for a drug to achieve its effect,
higher means lower dose required
Michaelis-Menten Curve - __100% correct answer as Describes the rate of
enzymatic reactions
Km - __100% correct answer as Concentration of substrate at half of Vmax
Competitive Inhibitors - __100% correct answer as Increase Km, do not affect
Vmax
Noncompetitive Inhibitors - __100% correct answer as Decrease Vmax, do not
affect Km
cAMP (Gs) - __100% correct answer as Involved in signaling pathways for β1/2,
H2, D1, TSH, PTH, ACTH, FSH, LH
IP3 (Gq) - __100% correct answer as Involved in signaling pathways for α1, M1/3,
H1, GnRH, TRH
Tyrosine Kinase (RTK) - __100% correct answer as Signaling pathway for Insulin,
IGF-1, FGF
JAK-STAT Pathway - __100% correct answer as Signaling pathway for GH,
Prolactin, EPO, G-CSF
CD4⁺ T Cells - __100% correct answer as Subtypes include TH1, TH2, TH17, and
Treg, each with specific functions in immune response.
TH1 - __100% correct answer as Activates macrophages through IL-12 leading to
IFN-γ production.
TH2 - __100% correct answer as Activates eosinophils and promotes IgE
production via IL-4, IL-5, and IL-13.
TH17 - __100% correct answer as Recruits neutrophils through IL-17.
,Treg - __100% correct answer as Suppresses immune responses using IL-10 and
TGF-β.
CD8⁺ T Cells - __100% correct answer as Responsible for cytotoxic killing via
perforin/granzymes or FasL.
B Cell Activation - __100% correct answer as Requires CD40-CD40L interaction
and IL-4/IL-5 from CD4⁺ T cells.
Class Switching - __100% correct answer as The process where B cells change
the class of antibody they produce, influenced by cytokines.
IL-4 - __100% correct answer as Promotes class switching to IgE and IgG.
IL-5 - __100% correct answer as Promotes class switching to IgA.
Antibody Types - __100% correct answer as Includes IgM, IgG, IgA, IgE, and IgD,
each with distinct functions.
IgM - __100% correct answer as The first antibody produced; exists as a
pentamer.
IgG - __100% correct answer as The most abundant antibody in circulation; can
cross the placenta.
IgA - __100% correct answer as Provides mucosal immunity.
IgE - __100% correct answer as Involved in allergic reactions and defense against
parasites.
IgD - __100% correct answer as Function is unclear.
Classic Pathway - __100% correct answer as Activation of the complement
system via IgG or IgM leading to C1 activation.
Alternative & Lectin Pathways - __100% correct answer as Complement activation
triggered directly by microbial components.
C3b - __100% correct answer as Acts as an opsonin in the complement system.
C5a - __100% correct answer as Functions in neutrophil chemotaxis.
, MAC (C5b-C9) - __100% correct answer as Forms a membrane attack complex
leading to cell lysis.
C1 esterase inhibitor deficiency - __100% correct answer as Causes hereditary
angioedema.
C5-C9 deficiency - __100% correct answer as Leads to recurrent Neisseria
infections.
Hypersensitivity Reactions - __100% correct answer as Classified into four types
based on mechanism and examples.
Type I Hypersensitivity - __100% correct answer as IgE-mediated reactions such
as anaphylaxis and asthma.
Type II Hypersensitivity - __100% correct answer as Involves IgG/IgM binding to
cells, causing cytotoxic effects.
Type III Hypersensitivity - __100% correct answer as Characterized by immune
complex formation, examples include SLE and serum sickness.
Type IV Hypersensitivity - __100% correct answer as T-cell mediated reactions,
delayed response (48-72 hours), examples include TB test.
X-linked Agammaglobulinemia (Bruton) - __100% correct answer as
Characterized by no B cells leading to recurrent bacterial infections.
Selective IgA Deficiency - __100% correct answer as Most common
immunodeficiency, leads to recurrent mucosal infections.
DiGeorge Syndrome - __100% correct answer as Caused by a 22q11 deletion
resulting in no thymus and recurrent infections.
IL-12 Receptor Deficiency - __100% correct answer as Results in decreased IFN-
γ and weak TH1 response, leading to mycobacterial infections.
SCID (Severe Combined Immunodeficiency) - __100% correct answer as
Characterized by decreased B and T cells, often referred to as 'bubble baby' disease.
Wiskott-Aldrich Syndrome (WAS) - __100% correct answer as X-linked condition
with thrombocytopenia, eczema, and recurrent infections.
Answers | Complete CBSE Exam for USMLE
Exam
Cell Cycle Phases - __100% correct answer as G1 → S → G2 → M
G1/S Checkpoint - __100% correct answer as Controlled by Rb protein
G2/M Checkpoint - __100% correct answer as Controlled by p53 protein
p53/p21 - __100% correct answer as Tumor suppressors
Cyclins/CDKs - __100% correct answer as Regulate progression of the cell cycle
Rb phosphorylation - __100% correct answer as Promotes cell cycle progression
Bioavailability (F) - __100% correct answer as Fraction of drug reaching systemic
circulation
Half-life (t½) - __100% correct answer as t½ = 0.693 × Vd / CL
Volume of Distribution (Vd) - __100% correct answer as Increases for lipophilic
drugs
Clearance (CL) - __100% correct answer as CL = Rate of elimination / [Drug]
Loading Dose (LD) - __100% correct answer as LD = Cp × Vd / F
Maintenance Dose (MD) - __100% correct answer as MD = Cp × CL × τ / F
Agonists - __100% correct answer as Bind and activate receptors
Antagonists - __100% correct answer as Block receptors
Competitive Antagonists - __100% correct answer as Cause a right shift in the
dose-response curve, same maximum effect
,Noncompetitive Antagonists - __100% correct answer as Decrease maximum
effect of the agonist
Efficacy - __100% correct answer as Maximum response of a drug, higher is
better
Potency - __100% correct answer as Dose needed for a drug to achieve its effect,
higher means lower dose required
Michaelis-Menten Curve - __100% correct answer as Describes the rate of
enzymatic reactions
Km - __100% correct answer as Concentration of substrate at half of Vmax
Competitive Inhibitors - __100% correct answer as Increase Km, do not affect
Vmax
Noncompetitive Inhibitors - __100% correct answer as Decrease Vmax, do not
affect Km
cAMP (Gs) - __100% correct answer as Involved in signaling pathways for β1/2,
H2, D1, TSH, PTH, ACTH, FSH, LH
IP3 (Gq) - __100% correct answer as Involved in signaling pathways for α1, M1/3,
H1, GnRH, TRH
Tyrosine Kinase (RTK) - __100% correct answer as Signaling pathway for Insulin,
IGF-1, FGF
JAK-STAT Pathway - __100% correct answer as Signaling pathway for GH,
Prolactin, EPO, G-CSF
CD4⁺ T Cells - __100% correct answer as Subtypes include TH1, TH2, TH17, and
Treg, each with specific functions in immune response.
TH1 - __100% correct answer as Activates macrophages through IL-12 leading to
IFN-γ production.
TH2 - __100% correct answer as Activates eosinophils and promotes IgE
production via IL-4, IL-5, and IL-13.
TH17 - __100% correct answer as Recruits neutrophils through IL-17.
,Treg - __100% correct answer as Suppresses immune responses using IL-10 and
TGF-β.
CD8⁺ T Cells - __100% correct answer as Responsible for cytotoxic killing via
perforin/granzymes or FasL.
B Cell Activation - __100% correct answer as Requires CD40-CD40L interaction
and IL-4/IL-5 from CD4⁺ T cells.
Class Switching - __100% correct answer as The process where B cells change
the class of antibody they produce, influenced by cytokines.
IL-4 - __100% correct answer as Promotes class switching to IgE and IgG.
IL-5 - __100% correct answer as Promotes class switching to IgA.
Antibody Types - __100% correct answer as Includes IgM, IgG, IgA, IgE, and IgD,
each with distinct functions.
IgM - __100% correct answer as The first antibody produced; exists as a
pentamer.
IgG - __100% correct answer as The most abundant antibody in circulation; can
cross the placenta.
IgA - __100% correct answer as Provides mucosal immunity.
IgE - __100% correct answer as Involved in allergic reactions and defense against
parasites.
IgD - __100% correct answer as Function is unclear.
Classic Pathway - __100% correct answer as Activation of the complement
system via IgG or IgM leading to C1 activation.
Alternative & Lectin Pathways - __100% correct answer as Complement activation
triggered directly by microbial components.
C3b - __100% correct answer as Acts as an opsonin in the complement system.
C5a - __100% correct answer as Functions in neutrophil chemotaxis.
, MAC (C5b-C9) - __100% correct answer as Forms a membrane attack complex
leading to cell lysis.
C1 esterase inhibitor deficiency - __100% correct answer as Causes hereditary
angioedema.
C5-C9 deficiency - __100% correct answer as Leads to recurrent Neisseria
infections.
Hypersensitivity Reactions - __100% correct answer as Classified into four types
based on mechanism and examples.
Type I Hypersensitivity - __100% correct answer as IgE-mediated reactions such
as anaphylaxis and asthma.
Type II Hypersensitivity - __100% correct answer as Involves IgG/IgM binding to
cells, causing cytotoxic effects.
Type III Hypersensitivity - __100% correct answer as Characterized by immune
complex formation, examples include SLE and serum sickness.
Type IV Hypersensitivity - __100% correct answer as T-cell mediated reactions,
delayed response (48-72 hours), examples include TB test.
X-linked Agammaglobulinemia (Bruton) - __100% correct answer as
Characterized by no B cells leading to recurrent bacterial infections.
Selective IgA Deficiency - __100% correct answer as Most common
immunodeficiency, leads to recurrent mucosal infections.
DiGeorge Syndrome - __100% correct answer as Caused by a 22q11 deletion
resulting in no thymus and recurrent infections.
IL-12 Receptor Deficiency - __100% correct answer as Results in decreased IFN-
γ and weak TH1 response, leading to mycobacterial infections.
SCID (Severe Combined Immunodeficiency) - __100% correct answer as
Characterized by decreased B and T cells, often referred to as 'bubble baby' disease.
Wiskott-Aldrich Syndrome (WAS) - __100% correct answer as X-linked condition
with thrombocytopenia, eczema, and recurrent infections.
