Which statement correctly describes viral envelopes?

• A. All viruses have envelopes
• B. Viral envelopes are made exclusively of proteins
• C. Viral envelopes are composed of DNA
• D. Viral envelopes are derived from host membranes and contain viral glycoproteins

Answer: (D)

Viral envelopes are lipid membranes that surround some viruses and are derived from the host cell’s membranes as the virus buds off. They are not made of DNA or protein alone; instead, they are a lipid bilayer taken from the host, embedded with viral glycoproteins that the virus uses to attach to and fuse with a new host cell. This is why enveloped viruses can enter by membrane fusion facilitated by those glycoproteins, while non-enveloped viruses lack this lipid layer. The statement that envelopes come from host membranes and include viral glycoproteins correctly captures their origin and key components.