Capsid

Definition

A capsid is the protein shell of a virus that encases its genetic material. It plays a crucial role in protecting viral nucleic acids and aiding in their delivery into host cells.

5 Must Know Facts For Your Next Test

1. Capsids are composed of protein subunits called capsomeres.
2. The structure of a capsid can be helical, icosahedral, or complex.
3. Capsids protect viral genetic material from degradation by enzymes and environmental factors.
4. During viral infection, the capsid facilitates the attachment and entry of the virus into host cells.
5. Some viruses have an additional lipid envelope surrounding the capsid, derived from the host cell membrane.

Review Questions

• What is the primary function of a capsid in a virus?
• Name two types of structures that a viral capsid can have.
• How does the capsid aid in the infection process of a host cell?

Related terms

Capsomere: Protein subunit that makes up the capsid.

Nucleocapsid: Complex of viral genetic material enclosed within a protein capsid.

Viral Envelope:

Lipid membrane surrounding some viruses, derived from host cell membranes.