Stimulated B Lymphocytes Switch from the Synthesis of Membrane-Bound to Secreted

question 12

Multiple Choice

Stimulated B lymphocytes switch from the synthesis of membrane-bound to secreted antibody molecules by increasing the concentration of a subunit of the trimeric CstF complex that cleaves and polyadenylates mRNAs. How does this up-regulation of CstF bring about the production of soluble antibodies?

• A) It favors a strong polyadenylation site in the immunoglobulin primary transcript, creating a longer antibody molecule that is secreted.
• B) It activates a weak polyadenylation site in the immunoglobulin primary transcript and prevents splicing, creating a shorter molecule that is secreted.
• C) It favors a strong polyadenylation site in the immunoglobulin primary transcript, creating a shorter antibody molecule that is secreted.
• D) It activates a weak polyadenylation site in the immunoglobulin primary transcript, creating a longer antibody molecule that is secreted.
• E) It favors a strong polyadenylation site in the immunoglobulin primary transcript, aborting translation and creating a shorter antibody molecule that is secreted.

---

Definitions:

Myelinated Axons

Axons that are covered with myelin, a fatty substance that insulates the axon and increases the speed of electrical signal transmission.

Somatic Motor Nervous System

Part of the peripheral nervous system that transmits signals from the central nervous system to skeletal muscles, enabling voluntary movements.

Autonomic Nervous System

A part of the nervous system responsible for controlling involuntary body functions, such as heart rate, digestion, and respiratory rate.

Autonomic Nervous System

The part of the nervous system responsible for control of bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.