Question

Viruses have

• A. DNA enclosed in a protein coat
• B. prokaryotic nucleus
• C. single chromosome
• D. both DNA and RNA

Answer 1

The Correct Option is A

The question concerns the basic nature and structure of viruses, which is an important topic in biology.

Viruses are unique biological entities, as they contain genetic material in the form of nucleic acids, which can be either DNA or RNA. However, crucially important is the fact that this genetic material is enclosed in a protein coat called a capsid.

Let's briefly discuss the options to understand why "DNA enclosed in a protein coat" is the most suitable answer:

• DNA enclosed in a protein coat: This is the correct description of many viruses. The genetic material (DNA) is wrapped inside a protein shell, which helps protect it and enables the virus to enter host cells.
• Prokaryotic nucleus: Viruses do not have cellular structures like a nucleus. They are sub-cellular entities and so cannot be correctly described as having a "prokaryotic nucleus" or any kind of nucleus.
• Single chromosome: This description is typically associated with bacteria, not viruses. Viruses have either DNA or RNA, not structured into chromosomes like in cellular organisms.
• Both DNA and RNA: Viruses contain either DNA or RNA but not both. The two types of viruses are DNA viruses and RNA viruses, depending on which type of nucleic acid they possess.

Therefore, the correct answer is that viruses have "DNA enclosed in a protein coat," and this protein coat plays a role in virus protection and host cell invasion.