Final answer:
A satellite virus is a noncellular infectious form that requires both a host cell and a helper virus for replication. They are obligate intracellular parasites, unable to replicate on their own without the cellular machinery of a host and the replication machinery of another virus.
Step-by-step explanation:
A noncellular infectious form that depends on other viruses for replication is known as a satellite virus. This type of virus lacks the ability to replicate independently and must hijack not only the cellular machinery of its host but also the replication machinery of a helper virus.
Viruses are fascinating entities that exist at the edge of life. They are obligate intracellular parasites that must infect a host cell to reproduce. Unlike living organisms that exhibit growth, metabolism, and reproduction through cell division, viruses cannot perform these functions on their own. They have a simple structure: genetic material enclosed within a protein coat, and they lack cellular components like a plasma membrane, cytoplasm, ribosomes, and organelles.
For replication, a virus must go through several steps: attachment to the host cell, penetration of its genetic material, replication, assembly of new virions, and release. The specificity of viral infection depends on the presence of particular receptors on the host cell's surface which the virus can bind to.
Once inside a host cell, the virus uses the cell's resources, including nucleotides, amino acids, and enzymatic machinery, to synthesize its proteins and replicate its genetic material. Ultimately, progeny virions are assembled and exit the host cell to infect new cells.