Question

Which of the following is always present in a Virus?

• A. Capsid
• B. Envelope
• C. Ribosome
• D. Mitochondria

Hint:

Remember: \[ \text{Virus} = \text{Nucleic acid} + \text{Capsid} \]
• Capsid \(\rightarrow\) Always present
• Envelope \(\rightarrow\) Optional
• Ribosomes/Organelles \(\rightarrow\) Absent in viruses

Answer 1

The Correct Option is A

Concept: A virus is an acellular infectious particle composed mainly of:
• Genetic material (DNA or RNA)
• A protective protein coat called the capsid The capsid surrounds and protects the viral nucleic acid. It is an essential structural component present in all viruses. Some viruses may additionally possess an envelope, but it is not universal.

Step 1: Identifying the structure always present in viruses. Every virus contains: \[ \text{Nucleic acid} + \text{Capsid} \] The capsid is made of protein subunits called capsomeres and helps in:
• Protection of viral genome
• Attachment to host cells
• Determining viral shape Therefore: \[ \boxed{\text{Capsid is always present in viruses}} \]

Step 2: Eliminating the incorrect options.
• Option (B): Viral envelope is present only in enveloped viruses such as HIV and Influenza virus.
• Option (C): Viruses do not possess ribosomes and depend on host ribosomes for protein synthesis.
• Option (D): Viruses are acellular and do not contain organelles such as mitochondria. Hence, the correct answer is Capsid.