M250 EXAM 4 2026 CERTIFICATION
EVALUATION SCRIPT SOLUTIONS GRADED
A+
⩥ MHC I vs MHC II.
Answer: MHC I presents intracellular antigens to CD8 cytotoxic T cells;
MHC II presents extracellular antigens to CD4 helper T cells.
⩥ CD4 vs CD8 markers.
Answer: CD4 is expressed on helper T cells; CD8 is expressed on
cytotoxic T cells.
⩥ Antigen-independent stage of lymphocyte development.
Answer: B and T cells undergo DNA recombination to generate diverse
antigen receptors before antigen exposure.
⩥ Antigen-dependent stage of lymphocyte development.
Answer: Specific lymphocytes are activated by antigen leading to clonal
expansion and memory cell formation.
⩥ Immunoglobulin (antibody) basic structure.
Answer: Y‑shaped molecule composed of 2 heavy and 2 light chains.
, ⩥ Fab vs Fc region.
Answer: Fab binds antigen; Fc interacts with immune cells and
complement.
⩥ Variable vs constant regions of antibodies.
Answer: Variable regions determine antigen specificity; constant regions
determine antibody function.
⩥ Classes of antibodies and their main roles.
Answer: IgG = most abundant, crosses placenta; IgM = first produced;
IgA = mucosal immunity; IgE = allergies; IgD = B‑cell receptor.
⩥ Which antibodies fix complement.
Answer: IgG and IgM activate the classical complement pathway.
⩥ Primary vs secondary immune response.
Answer: Primary is slow with lower antibody levels; secondary is rapid
and stronger due to memory cells.
⩥ Why memory cells remove the lag phase.
Answer: Memory cells respond immediately upon re‑exposure.
⩥ Opsonization.
EVALUATION SCRIPT SOLUTIONS GRADED
A+
⩥ MHC I vs MHC II.
Answer: MHC I presents intracellular antigens to CD8 cytotoxic T cells;
MHC II presents extracellular antigens to CD4 helper T cells.
⩥ CD4 vs CD8 markers.
Answer: CD4 is expressed on helper T cells; CD8 is expressed on
cytotoxic T cells.
⩥ Antigen-independent stage of lymphocyte development.
Answer: B and T cells undergo DNA recombination to generate diverse
antigen receptors before antigen exposure.
⩥ Antigen-dependent stage of lymphocyte development.
Answer: Specific lymphocytes are activated by antigen leading to clonal
expansion and memory cell formation.
⩥ Immunoglobulin (antibody) basic structure.
Answer: Y‑shaped molecule composed of 2 heavy and 2 light chains.
, ⩥ Fab vs Fc region.
Answer: Fab binds antigen; Fc interacts with immune cells and
complement.
⩥ Variable vs constant regions of antibodies.
Answer: Variable regions determine antigen specificity; constant regions
determine antibody function.
⩥ Classes of antibodies and their main roles.
Answer: IgG = most abundant, crosses placenta; IgM = first produced;
IgA = mucosal immunity; IgE = allergies; IgD = B‑cell receptor.
⩥ Which antibodies fix complement.
Answer: IgG and IgM activate the classical complement pathway.
⩥ Primary vs secondary immune response.
Answer: Primary is slow with lower antibody levels; secondary is rapid
and stronger due to memory cells.
⩥ Why memory cells remove the lag phase.
Answer: Memory cells respond immediately upon re‑exposure.
⩥ Opsonization.
