What are viruses made of?

We often come into contact with some viruses in our daily lives, which can cause diseases in our bodies, such as common viral colds, etc. Viral diseases can only be cured through antiviral treatment, and the treatment time of viral diseases is generally longer than that of bacterial diseases. Therefore, we must distinguish the types of diseases, which can facilitate treatment. So what are viruses composed of?

First, what are viruses made of? Viruses are mainly composed of internal genetic material and a protein shell. Since viruses are a type of non-cellular organism, a single virus individual cannot be called a "single cell", thus giving rise to virus particles or virions. Virions are sometimes also called virus particles or virus particles, which refer specifically to mature, structurally complete and infectious single viruses. The nucleic acid is located in its center, called the core or genome, and the protein surrounds the core to form a capsid. The capsid is the main scaffold structure and antigenic component of the virus particle, and has the function of protecting nucleic acid, etc. The capsid is composed of many morphological subunits (subunits) - capsomeres (capsomere) that can be distinguished under an electron microscope. The core and capsid are collectively called the nucleocapsid. Some more complex viruses (usually animal viruses, such as influenza viruses) have a core shell covered by a lipid bilayer membrane containing protein or glycoprotein, which is called an envelope.

Second, the lipids in the envelope come from the host cell membrane. Some capsules also have appendages such as spikes. The presence or absence of an envelope and its properties are related to the virus's host specificity and invasion functions. There is a type of polyhedrosis virus among insect viruses, whose nucleocapsid is coated by protein crystals to form polygonal inclusion bodies. The process by which a virus replicates is called the replication cycle. It can be roughly divided into five consecutive stages: adsorption, invasion, proliferation, maturation (assembly), and lysis (release).

What are viruses made of? Viruses are mainly composed of nucleic acids and protein shells. Some viruses have an envelope and spikes, such as influenza viruses. The simplest virus has a nucleic acid core covered with a layer of regularly arranged protein subunits, called a capsid. The morphological subunits that make up the capsid are called capsomers, and the particle composed of nucleic acid and capsid protein is called nucleocapsid. More complex viruses also have an envelope composed of lipids and glycoproteins. The nucleocapsid is divided into three modes according to the arrangement of the capsomers: icosahedral symmetry, such as polio virus; spiral symmetry, such as tobacco mosaic virus; and compound symmetry, such as even-numbered bacteriophage. There is also one or several glycoproteins on the lipid envelope, which form protrusions in shape, such as the hemagglutinin and neuraminidase of influenza virus. Among insect viruses, there is a type of polyhedrosis virus whose nucleocapsid is coated by protein crystals to form polygonal inclusion bodies.

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