Question

A virus contains
1. DNA only
2. RNA only
3. Protein only
4. Protein and nucleic acid

Answer 1

Correct Answer - Option 4 : Protein and nucleic acid

Concept-

• Viruses did not find a place in classification since they are not considered truly ‘living’.
• Viruses are non-cellular organisms.
• The name virus that means venom or poisonous fluid was given by Dmitri Ivanowsky.
• Viruses cause diseases like mumps, smallpox, herpes, and influenza.

Explanation-

Viruses are mainly composed of nucleic acid and protein.

• The protein coat called capsid made of small subunits called capsomeres protects the nucleic acid. 

• Nucleic acids consist of DNA and RNA.
• Protein and Nucleic acid together called the nucleocapsid.

• The nucleic acid that is the double or single-stranded DNA or RNA forms the genetic makeup of the virus.

• Viruses could be crystallized and crystals consist largely of proteins. They are inert outside their specific host cell.
• Viruses are of different types based on host-
  • Phytophages (Plant viruses)- viruses infect the plants.
  • Zoophages (Animal viruses)- viruses infect the animals.
  • Bacteriophages- viruses infect bacteria.
  • Cyanophages- viruses infect blue-green-algae.
  • Zymophages- viruses infect yeasts.