W12 BMS1062

Which is false about clonal selection theory?

• Antigen receptor acitvation causes cell proliferation
• Each lymphocyte only expresses 1 type of receptor
• Antigen receptors are generated after antigen exposure
• Activated clones differentiate into effector cells

What is true about the T-cell and B-cell receptors?

• They are completely identical in the variable and constant regions
• TCR α-chain and BCR heavy chain have only V and J variable regions
• TCR β-chain and BCR heavy chain have VD and J variable regions
• Chains of both receptors are held together with ionic bonds

How many complementary-determining regions (CDRs) does a single B-lymphocyte receptor have?

• 12
• 6
• 3
• 9

What is involved in non-homologous end-joining?

• DNA glycosylase
• Ku protein
• Translesion polymerase
• AP endonuclease

How does a strand invade in E.coli in homologous recombination?

• Uses RecA and ATP
• Uses Rad51 and GTP
• Uses Rag1 and GTP
• Uses Rad51 and ATP

When in meiosis do homologous chromosomes segregate?

• Anaphase II
• Anaphase I
• Telophase I
• Metaphase I

Which enzyme is involved in creating a double-stranded break in meiosis?

• Moe12
• RecA
• Rad51
• Spo11

Which of the following does NOT apply to non-homologous end joining?

• Rejoining of broken ends by DNA ligase
• Uses the Ku protein
• Usually a loss of nucleotides at the site of joining
• Uses the sister chromatid as a template