MICR 3230 Final Exam Questions with All Correct Answers 2026/2027 Updated.

MICR 3230 Final Exam Questions with
All Correct Answers 2026/2027 Updated.
Binding affinity - Answer Strength of an individual bond



Binding avidity - Answer Combined strength of binding of the multiple interactions



Multivalency influences which binding property? - Answer increases avidity of the interactions



Dissociation constant - Answer Kd

- measure of strength of ligand binding



Ligand-receptor binding induces 4 molecular changes in the receptor - Answer 1.
Conformational

2. Dimerization / clustering

3. Location in the membrane

4. Covalent modification



Extended contact between ligands and receptors result in? - Answer - facilitates signal
transduction and exchange of cytokine signals

- may lead to cytoskeletal reorganization



3 common features of immune receptors - Answer 1. Immunoglobulin domains

2. Transmembrane, cytosolic or secreted

3. If the receptor is lacking a C-terminus transmembrane segment, it gets secreted



B-cell receptor (BCR) as an antigen receptor - Answer contains an antibody of defined
specificity



T-cell receptor (TCR) as an antigen receptor - Answer specificity is for peptides derived from
APC degraded antigen presented on MHC molecules



CD4 and CD8 as an antigen receptors - Answer T-cell co-receptors that define different subsets
of T-cell function

,Antigen specificity for antibodies is based off of? - Answer interaction between light and heavy
chain variable regions



Antibody effector activity - Answer - phagocytosis

- complement fixation



Constant vs variable regions of antibody - Answer Constant - effector activity



Variable - antigen binding



Complementary determining regions - Answer Three sites form antibody combining site

- CDR1, CDR2 and CDR3



Framework region - Answer - the relatively invariant amino acid sequences within the variable
domains

- responsible for folding of the CDRs to form ACS



Heavy chain antibody isotopes - Answer IgA (alpha)

IgD (delta)

IgE (epsilon)

IgG (gamma)

IgM (mu)



Light chain antibody isotopes - Answer Kappa

Lambda



Which antibody molecules form a B-cell receptor complex to transduce signals? - Answer - IgA
and IgB transduce signals via immunoreceptor tyrosine-based activation motifs (ITAMs)

- CD19, CD81 and CD21 transmit and relay signals to the cell interior via CR2



How do lipid rafts benefit receptor signaling? - Answer Receptors cluster into lipid rafts and
this allows for movement of receptors

- leads to better binding



V(D)J recombination - Answer Rearrange variable (V)

Joining (J)

, Diversity (D)



Results in novel amino acid sequences in antigen-binding regions



When is the (D)iversity applicable? - Answer Only in antibody heavy chains



Multigene organization of Ig genes - Answer Lambda light chain gene located on chromosome
22



Kappa light chain gene located on chromosome 2



Heavy chain gene located on chromosome 14



Multigene gene organization: pairings - Answer Kappa genes pair each V segment with J
segment



Lambda genes pair each J segment with a (C)onstant segment



How many possible VJDC combinations are there? - Answer Heavy: V(45) x D(23) x J(6)



Kappa: V(41) x J(5)



Lambda: V(33) x J(5)



Recombination signal sequences - Answer - flank each antibody gene segment

- allow antibody to recognize many different antigens



12/23 rule - Answer 12 bp RSS must pair with a 23 bp RSS

- one turn spacer with a two turn spacer



Recombination activating gene (RAG) - Answer RAG1/2 complex is responsible for recognizing
and cutting DNA at the immunoglobulin-encoding region and the RSS



1. RAG1 forms a complex with RSSs

2. Complex stabilized by RAG2