front 1 1. Which type of recombination occurs between non-identical sequences? A. Homologous recombination B. Site-specific recombination C. Non-homologous recombination D. Conservative recombination | back 1 C. Non-homologous recombination |
front 2 2. Which statement best describes innate immunity receptors? A. Highly specific and diverse B. Encoded directly in the germline C. Generated by somatic recombination D. Produced only after infection | back 2 B. Encoded directly in the germline |
front 3 3. The process of generating B and T cell receptor diversity is called: A. Somatic hypermutation B. Gene amplification C. Somatic recombination D. Antigen drift | back 3 C. Somatic recombination |
front 4 4. Which enzyme adds random nucleotides during junctional diversity? A. Artemis B. TdT C. RAG1 D. RAG2 | back 4 B. TdT |
front 5 5. The 12/23 rule ensures: A. Pairing of identical RSS sequences B. Random mutation of heavy chains C. Correct pairing between gene segments D. Binding of cytokines to receptors | back 5 C. Correct pairing between gene segments |
front 6 6. A defective RAG1/2 complex leads to: A. Multiple sclerosis B. Rheumatoid arthritis C. Severe Combined Immunodeficiency (SCID) D. Chronic granulomatous disease | back 6 C. Severe Combined Immunodeficiency (SCID) |
front 7 7. What is the purpose of the leader (L) sequence in immunoglobulin genes? A. Enzyme activation B. Cell surface expression regulation C. DNA repair D. Peptide cleavage | back 7 B. Cell surface expression regulation |
front 8 8. Which chain lacks a D (diversity) region? A. Heavy chain B. α chain C. Light chain D. β chain | back 8 C. Light chain |
front 9 9. Which molecule cuts open DNA hairpins during recombination? A. TdT B. Artemis C. Tapasin D. ERAP | back 9 B. Artemis |
front 10 10. What is allelic exclusion? A. Deletion of one allele for protein balance B. Preventing rearrangement on the second allele after a productive one C. Allowing both alleles to express simultaneously D. Recombination of both heavy chains | back 10 B. Preventing rearrangement on the second allele after a productive one |
front 11 11. The main difference between αβ and γδ T cells is: A. Their location in the thymus B. The TCR chains they express C. The cytokines they release D. The CD3 molecules they contain | back 11 B. The TCR chains they express |
front 12 12. The CD3 complex is required for: A. Ligand degradation B. Transport of TCR to the surface and signal transduction C. Nucleotide addition D. Peptide editing | back 12 B. Transport of TCR to the surface and signal transduction |
front 13 13. --Adds random nucleotides to DNA ends | back 13 B. TdT |
front 14 14. --Opens DNA hairpins during recombination | back 14 C. Artemis |
front 15 15. ___ Chooses and recombines gene segments randomly | back 15 A. RAG1/2 |
front 16 16. ___ Ensures proper MHC I folding in ER | back 16 E. Calnexin |
front 17 17.___ Trims peptide ends for MHC I loading | back 17 F. ERAP |
front 18 18. ___ Ensures only high-affinity peptides bind to MHC I | back 18 D. Tapasin |
front 19 19. Differentiate between homologous and non-homologous recombination. | back 19 Homologous: identical sequences; Non-homologous: non-identical (e.g., site-specific, translocation). |
front 20 20. Compare receptor specificity and diversity in innate vs adaptive immunity. | back 20 Innate = limited/germline; Adaptive = highly specific and diverse. |
front 21 21. What are the three mechanisms that generate receptor diversity in lymphocytes? | back 21 Somatic recombination, combinatorial diversity, junctional diversity |
front 22 22. Define “recognition signal sequences” (RSS) and describe their components. | back 22 RSS = noncoding DNA guiding recombination; includes heptamer, spacer (12 or 23 bp), and nonamer. |
front 23 23. Explain the 12/23 rule and its biological purpose. | back 23 Ensures 12 bp RSS pairs with 23 bp RSS → correct gene segment pairing. |
front 24 24. Describe how combinatorial diversity contributes to receptor variation. | back 24 Random pairing of heavy and light chain variable regions |
front 25 25. What is junctional diversity, and which enzymes are involved? | back 25 Cutting/rejoining DNA segments; uses RAG1/2, TdT, Artemis. |
front 26 26. Explain the process and purpose of allelic exclusion. | back 26 Stops rearrangement on second allele after successful one → ensures one receptor per cell. |
front 27 27. Compare αβ and γδ T cells in structure and function. | back 27 αβ = majority, adaptive response; γδ = minor, innate-like, mucosal surfaces. |
front 28 28. What are the components and functions of the TCR/CD3 complex? | back 28 Components: CD3γ, CD3δ, CD3ε, ζ chain; Functions: transport TCR to surface, signal transduction. |