An isolated biological agent undergoes crystallization when stored in a sterile nutrient broth outside host cells. However, upon entry into a susceptible living host cell, it initiates replication. Which of the following best explains why this agent is incapable of independent metabolic activity outside a host?
- It lacks cellular structures such as cytoplasm, ribosomes, and metabolic enzymes necessary for self-sustained protein synthesis.Answer
- BIts cytoplasm is enclosed by a semi-permeable cell membrane that becomes inactive when removed from host tissue.
- CIts membrane-bound organelles enter a dormant state outside host cells due to a lack of cellular ATP reserves.
- DIts peptidoglycan cell wall thickens in extracellular fluid, preventing the absorption of nutrient molecules.
Answer
It lacks cellular structures such as cytoplasm, ribosomes, and metabolic enzymes necessary for self-sustained protein synthesis.
The correct option correctly identifies that viruses are acellular entities lacking cytoplasm, ribosomes, and metabolic enzymes, rendering them incapable of self-sustained protein synthesis or metabolism outside a living host cell.
Step-by-Step Solution
Key Concept
Acellular nature and obligate intracellular parasitism of viruses