Before You Begin
Question #46532
The Question
In the context of host-parasite co-evolution, parasites typically evolve toward a state of commensalism (the 'prudence' rule) to avoid killing their host. However, HIV maintains extreme virulence, ultimately causing systemic immune collapse. Which specific dynamic of the HIV replication cycle best explains why it deviates from this evolutionary 'prudence' rule?
Options
- A.
It maximizes transmission by maintaining a high viral load, which necessitates the continuous destruction of CD4+ T-cells, while utilizing macrophages as surviving viral factories.
- B.
It undergoes rapid antigenic variation due to an error-prone reverse transcriptase, which forces the virus to kill the host before the immune system adapts.
- C.
It exclusively targets and destroys macrophages, completely preventing the presentation of viral antigens to the acquired immune system.
- D.
It forms a provirus that remains permanently dormant in the host genome, shifting its evolutionary strategy entirely to vertical transmission.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Helper_T_cells|Darwinian_Fitness|HIV
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the HIV replication cycle and ecological principles (parasitism) in isolation.
The pivot requires synthesizing NCERT Ecology (parasites shouldn't kill hosts) with NCERT Human Health (HIV destroys T-helper cells but spares macrophages).
The trap lies in distinguishing between the mechanism of immune evasion (Option B) and the evolutionary strategy of virulence (Option A), while remembering the exact cellular fate of macrophages vs.
T-cells.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | HIV Replication Cycle |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |