Which of the Following Mechanisms Contributes to the Change from B

question 8

Multiple Choice

Which of the following mechanisms contributes to the change from B cell production of membrane Ig to secreted Ig?

• A)V(D)J recombinase-mediated deletion of the exon encoding the transmembrane domain
• B)Alternative processing of primary RNA transcripts to remove the transmembrane domain and include a secretory tail piece
• C)Increased vesicular exocytosis of intracellular stores of the secretory form of Ig
• D)Switch recombinase-mediated recombination of the heavy chain locus to juxtapose the V(D)J segment with the exon encoding a secretory tail piece
• E)Up-regulation of ectoenzymes that proteolytically cleave membrane Ig heavy chains just proximal to the membrane

---

Definitions:

External Respiration

The exchange of gases between the atmosphere and the blood through the lung alveoli.

Pseudostratified Ciliated Columnar Epithelium

A type of epithelial tissue composed of irregularly shaped cells that appear to be stratified but are actually a single layer with cilia on their surface, commonly found lining the respiratory tract.

Goblet Cells

are mucus-secreting cells found in the epithelial linings of respiratory and intestinal tracts, helping to protect and lubricate the surfaces.

Epithelial Tissue

One of the four basic types of tissue, forming the protective covering or lining of many body surfaces and cavities.