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Difficulty: MediumViruses: Structure and Characteristics

Which of the following structural features is present in all complete virus particles (virions), regardless of the host species they infect?

  1. A protein capsid enclosing the nucleic acid genomeAnswer
  2. B
    An outer phospholipid envelope derived from host plasma membrane
  3. C
    A cytoplasmic matrix containing ribosomes for protein synthesis
  4. D
    A genome composed simultaneously of both DNA and RNA molecules

Answer

A protein capsid enclosing the nucleic acid genome
All virions fundamentally consist of a nucleic acid genome (either DNA or RNA) surrounded by a protein coat called a capsid. This basic nucleoprotein structure is universal to all viruses across all host types.

Step-by-Step Solution

1
Identify universal components of a virion
Every intact infectious virus particle consists minimally of a nucleic acid core enclosed by a protein coat termed a capsid.
The nucleoprotein complex (capsid plus genome) is the defining architectural unit of all viruses.
2
Evaluate variable and cellular components against viral characteristics
Lipid envelopes are restricted to enveloped viruses, while cytoplasm, organelles, and dual DNA/RNA genomes do not exist in viruses.
Viruses are acellular obligate intracellular parasites containing only one type of nucleic acid and lacking metabolic machinery.

Key Concept

Universal Viral Structure and Acellular Nature
Estimated Time:1m 0s
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Topics

Viruses: Structure and Characteristics

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