ATI RN
Lymphatic System Questions and Answers PDF Questions
Question 1 of 5
When complement proteins are covalently deposited onto the surface of a bacterium, this can sometimes lead to direct lysis of the bacterium. However, more commonly, the deposition of complement proteins onto the bacterial surface does not directly harm the bacterium. Instead, these complement proteins aid in bacterial elimination by:
Correct Answer: D
Rationale: Complement (e.g., C3b) enhances phagocytosis via complement receptors ; Fc receptors are antibody-related, not replication or B-cell stimulation .
Question 2 of 5
Scaffold proteins are often phosphorylated at multiple sites, allowing the recruitment of several different signaling proteins. In antigen receptor signaling pathways, this mechanism is used to bring enzymes in close proximity to their substrates. Termination of this signaling mechanism would be most efficiently accomplished by:
Correct Answer: D
Rationale: Dephosphorylation disrupts scaffold signaling; ubiquitination is slower, GAP or depletion are less direct.
Question 3 of 5
Natural killer cells
Correct Answer: B
Rationale: Natural killer (NK) cells release chemicals (e.g., perforin) to induce apoptosis in virus-infected cells, not phagocytosis or antibody tagging.
Question 4 of 5
The secondary immune response occurs when memory cells bind to
Correct Answer: C
Rationale: Memory cells respond to antigens in the secondary immune response, triggering a faster, stronger reaction, not hormones, antibodies, or plasma cells.
Question 5 of 5
The second vaccination is beneficial because
Correct Answer: B
Rationale: A second vaccination boosts memory cells, increasing antibody levels faster and stronger, not involving plasma cell survival or circulation.