The general phases in the life cycle of animal viruses include all the following except. a. Coating b. Adsorption c. Penetration d. Synthesis e. Assembly f. Release
The correct answer and explanation is:
The correct answer is a. Coating.
Explanation:
The life cycle of animal viruses generally follows a series of phases necessary for viral replication and production of new virus particles. These key phases include adsorption, penetration, synthesis, assembly, and release.
- Adsorption is the initial step where the virus attaches to specific receptor sites on the surface of a susceptible host cell. This specificity determines the host range and tissue tropism of the virus.
- Penetration follows adsorption, where the virus or its genetic material enters the host cell. Penetration can occur through mechanisms such as endocytosis or fusion of the viral envelope with the cell membrane.
- Synthesis refers to the replication of viral nucleic acid and the production of viral proteins. During this phase, the viral genome is transcribed and translated using the host cell’s machinery. The synthesis phase varies depending on whether the virus has DNA or RNA as its genetic material.
- Assembly is the process where newly synthesized viral components are put together to form complete viral particles, often referred to as virions. This step occurs in specific areas of the cell, such as the nucleus or cytoplasm, depending on the virus.
- Release is the final phase, where mature virions exit the host cell to infect new cells. This can happen by cell lysis, which destroys the host cell, or by budding, which allows enveloped viruses to exit while acquiring their envelope from the host cell membrane.
Coating is not a recognized phase in the life cycle of animal viruses. The term may sometimes be confused with uncoating, which is a critical step but not called coating. Uncoating occurs after penetration, where the viral capsid is removed to release the viral genome inside the host cell. Since “coating” implies adding a coat, which is not part of the virus replication cycle, it is not included among the main phases.
Therefore, “coating” does not belong to the standard phases of the animal virus life cycle.