Which of the following is a component that a
Cell wall
Internal organelles
Outer envelope
Spikes
The correct answer and explanation is:
Correct Answer: D. Spikes
A capsid virus must contain spikes, which are protein structures that extend from the surface of the virus. These spikes are essential for the virus’s ability to recognize and attach to host cells. They bind to specific receptors on the surface of the host cell, initiating the process of viral entry.
The capsid itself is a protein shell that encloses the viral genetic material. It protects the nucleic acid and provides the structure needed for the virus to maintain its shape. The capsid may also play a role in delivering the viral genome into the host cell during infection. While the capsid is a critical component of all viruses, spikes are often embedded in or attached to the surface of the virus, especially in viruses with an envelope.
Spikes are particularly important in enveloped viruses, where they are anchored in the lipid membrane derived from the host cell. However, even non-enveloped viruses can have spike-like projections on their capsid that help with attachment and penetration.
The other options are not required components of a capsid virus:
- Cell wall is found in bacteria and plant cells, not viruses.
- Internal organelles such as mitochondria or nuclei are found in eukaryotic cells, but viruses are acellular and do not contain organelles.
- Outer envelope is present only in enveloped viruses, not in all capsid viruses. It is derived from the host cell’s membrane during the budding process. Therefore, it is not a universal feature of all viruses with a capsid.
In conclusion, spikes are a necessary component for many viruses with a capsid because they facilitate host cell recognition and attachment, which are the first critical steps in viral infection.