QUESTION 4
Explain the replication cycle of viruses as well as the different virus structures and genomes.
Viruses are microscopic infectious agents that are not considered living organisms because they lack the cellular structure and metabolic processes found in cells. Instead, viruses consist of genetic material (either DNA or RNA) encased in a protein coat, sometimes surrounded by a lipid envelope. The structure of viruses can vary widely, and they can be broadly categorized into different types based on their structural components.
Capsid: The capsid is the protein coat that surrounds the genetic material of a virus. It serves to protect the viral genome and often plays a crucial role in attaching to host cells.
Envelope: Some viruses, such as many types of enveloped viruses, have an additional lipid envelope surrounding the capsid. This envelope is derived from the host cell's membrane and contains viral proteins that aid in attachment and entry into host cells.
Genetic Material: Viral genetic material can be either DNA or RNA, single-stranded or double-stranded, linear or circular.
Tail Fibers and Tail Sheath: Bacteriophages have a capsid head that contains the genetic material and a tail that helps them attach to and inject their genetic material into bacterial cells. The tail often includes tail fibers and a sheath that contract to puncture the bacterial cell wall.
Spikes: Some viruses have spikes or glycoproteins on their surfaces, which are involved in attaching to host cell receptors. In the case of enveloped viruses, these spikes often protrude from the viral envelope.
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