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Difficulty: HardViruses: Structure and Characteristics

An isolated infectious pathogen is treated separately with a lipolytic enzyme that hydrolyzes phospholipids and an enzyme that selectively degrades ribose-containing nucleic acids. The pathogen retains its infectivity following lipid hydrolysis but loses infectivity after ribose nucleic acid degradation. Based on these structural properties, which of the following best classifies this pathogen?

  1. Non-enveloped RNA virusAnswer
  2. B
    Enveloped DNA virus
  3. C
    Bacterium possessing a peptidoglycan cell wall
  4. D
    Enveloped RNA virus

Answer

Non-enveloped RNA virus
The pathogen's resistance to phospholipid hydrolysis confirms the absence of a outer lipid membrane envelope surrounding its protein capsid. Its loss of infectivity upon exposure to ribose nucleic acid degradation proves that its genetic material is RNA rather than DNA. Therefore, the pathogen is correctly identified as a non-enveloped RNA virus.

Step-by-Step Solution

1
Analyze the effect of phospholipid hydrolysis on pathogen infectivity.
The pathogen remains infectious, indicating it does not possess a phospholipid bilayer membrane or lipid envelope.
Enveloped viruses and cellular organisms rely on intact phospholipid membranes for host infection and structural integrity.
2
Analyze the effect of ribose nucleic acid degradation on infectivity.
The pathogen loses infectivity, confirming its genetic material is RNA containing ribose sugars.
Ribose-degrading enzymes target RNA specifically without degrading deoxyribose nucleic acid (DNA).
3
Synthesize the structural features to classify the organism.
The pathogen is a non-enveloped RNA virus.
Combining a protein capsid lacking a lipid envelope with an RNA genome uniquely defines a non-enveloped RNA virus.

Key Concept

Structural composition of viruses: viral envelopes and genome types
Estimated Time:1m 30s
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Topics

Viruses: Structure and Characteristics

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