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What are the main components of a virus?

Virus consists of two main components - The nucleic acid (either DNA or RNA) and a protein coat. 2. Viruses have either single stranded or double stranded DNA or RNA as genetic material.

What are the different shapes of viruses?

Viral shapes, such as spherical or icosahedral, vary considerably based on the virus's host type. However, all viruses infect their hosts in a similar way. When a virus enters a cell, it falls apart into its two components: nucleic acids and proteins.

What is the third step in the life cycle of a virus?

Uncoating is the third step that occurs in enveloped viruses, when the virion enters a host cell and viral DNA or RNA is freed from the capsid and viral envelope. 4. Synthesis, the fourth step in the virus life cycle, occurs when the virus directs the host cell's metabolism to produce the virus's nucleic acid and protein.

How do viruses kill their hosts?

Viruses change the metabolism of their host in order to replicate, often killing the host in the process. This occurs through a life cycle involving multiple steps, each with specific processes that ensure viral survival. Viral replication occurs inside a host cell and typically greatly harms or kills that cell.

How do viruses get into the cell?

Endocytosis is a form of bulk transport that moves material into a cell by an infolding of the cell membrane around the material, forming a vesicle (small sac) that moves into the cell. The release stage also varies between viruses.

How does viral replication work?

Viral Replication. Viruses change the metabolism of their host in order to replicate, often killing the host in the process. This occurs through a life cycle involving multiple steps, each with specific processes that ensure viral survival. Viral replication occurs inside a host cell and typically greatly harms or kills that cell.

What are the steps of replication?

Replication occurs within the six distinctive steps of the virus life cycle. 1. Attachment is the first step in the virus life cycle, in which a virion attaches to a host cell's surface. 2. Penetration is the second step in the virus life cycle, when the virion enters or injects its nucleic acid into the host cell. 3.

Where does the virion envelope replicate?

The virion envelope is constructed from parts of the host plasma membrane in the process. The location of replication differs among viruses. Bacteriophages and most RNA viruses replicate in the host cell cytoplasm, whereas many DNA viruses replicate in the nucleus of eukaryotic host cells.

Does exocytosis kill the host cell?

Budding, typical in enveloped viruses, does not kill the host cell. Nor does exocytosis, common in nonenveloped viruses.

What is the component of a viral chromosome?

Component # 1. Nucleoid: It represents the viral chromosome. Nucleoid or viral chromosome is made of a single molecule of nucleic acid. It may be linear or circular with various degrees of coiling. Nucleoid is the infective part of virus. The nucleic acid is either DNA or RNA but never both.

What is the capsid of a virus?

Capsid (Sheath, Coat): It is the proteinaceous covering around the virus which protects the nucleoid from damage from physical and chemical agents. The capsid consists of a number of subunits called capsomeres or capsomers. The capsid of TMV has 2130 capsomeres.

What is the difference between RNA and DNA viruses?

DNA containing viruses are called de-oxy-viruses while RNA-containing viruses are termed as riboviruses. Each of them has two subtypes, double stranded and single stranded.

What is an envelope in a virus?

Envelope: It is a loose membranous covering that occurs in some animal viruses, rarely plant and bacterial viruses. In contrast to enveloped viruses, the viruses without an envelope are called naked. Envelope consists of proteins from (virus), lipids and carbohy­drates (from host).

Where is lysozyme present in a virus?

They are occasional. Enzyme lysozyme is present in the region that comes in contact with host cell in bacteriophages. Other enzymes are neuraminidase in Influenza Virus, RNA polymerase, RNA transcriptase, reverse transcriptase.