Question

What is the importance of viruses that are enveloped VS. naked?

Answer 1

Envelope :-

• It is the outer thin loose Covering composed of proteins ( from the virus ) , lipids & carbohydrates ( both from host ).
• Its subunits are called peplomers.
• Envelope may be present or absent in a virus. Based on this virus can be classified in 2 types ,

YOU CAN FIND A SIMPLE DIAGRAM AND OF ENVELOPED Vs NON ENVELOPED VIRUS ALONG WITH THEIR RESPECTIVE EXAMPLES ABOVE.

Significance of Envelope in viruses :

• The Envelope helps viruses to avoid the host immune system as it contains some components of the cell membrane.
• The Viral glycoprotein on the surface of Envelopes serve to identify and attach to the receptor sites on the host cell membrane.
• Enveloped viruses are easier to get released via budding or exocytosis process , without disrupting the cell membrane.
• In contrast the unenveloped viruses can be released only by host cell lysis.
• So , unenveloped viruses can not get released until the assembly of viruses get completed. But enveloped viruses can be released as long as the first virus is ready. This enhances the efficiency of the whole viral replication process.
• And furthermore cell lysis is an highly immunogenic event , this reduces the immunogenicity and enables stealthy dissemination of viruses within the host body.

But there is also some backdrops of envelope as following ,

• As , lipid bilayer is very fragile , enveloped viruses are very vulnerable in the environment. HIV virus is a example which gets inactived in exposure to air.
• So it can be concluded that although envelope helps virus to survive inside host body to a great extent but it reduces the chance of survival in outer environment.

FIGURE - HIV VIRUS

The above image shows the envelope ( grey coloured )shielding most of the antigens ( orange coloured ) .