The nucleic acid of a virus particle is enclosed in a protein coat. What is this protein coat called?

• A. Capsid
• B. Envelope
• C. Capsule
• D. Nucleoid

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding the structure of a virus. Viruses are composed of genetic material (either DNA or RNA) surrounded by a protective layer, which is often a protein coat.
2. Step 2: Learn the terminology associated with viral structures. The protein coat that encloses the nucleic acid of a virus is specifically referred to as the 'capsid.'
3. Step 3: Differentiate between the terms provided in the options. For example, 'envelope' refers to a lipid bilayer that some viruses have outside the capsid, 'capsule' is a term used for bacterial structures, and 'nucleoid' refers to the region in prokaryotic cells where genetic material is located.
4. Step 4: Recognize that the capsid is the correct term for the protein coat that directly surrounds the nucleic acid in a virus particle.
5. Step 5: To reinforce understanding, visualize the virus structure: nucleic acid is enclosed by the capsid, and in some viruses, an envelope may surround the capsid.