Structure of viruses

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Structure of viruses

Viruses are non-living live on the outside of a host cell. They have of a strand of nucleic acid, which can be either DNA or  and they have a protective protein coat called the capsid around them. This capsid is made up from many protein molecules. They also have a tail section. Sometimes they have a further membrane of lipid, called an envelope which covers the protein.

The size of viruses varies from 20 nanometres at their smallest state to 300 nanometre at their biggest state. Some viruses contain ribonucleic acid which is also called RNA and other have deoxyribonucleic acid within the which is also known as DNA. These acids within the viruses are called genome. The nucleic acid can be single-stranded or double-stranded and it can be linear or a closed loop it can also be continuous or occur in segments.

A viruses infect a cell by attaching fibres from its protein tail to a specific receptor site on the wall of the bacterial cell, then it injects nucleic acid into the host.

Viruses’ classification is based on many factors, for example they could be classified based on their chemical and physical characters such as nucleic acids like DNA or RNA,

  • Also On their symmetry, whether they are helical complex or icosahedral
  • On the presence of envelope
  • On the diameter of their capsid
  • On the number of their capsomers
  • Codes solely for reproduction

There are two types of viruses, the regular bacteriophage and the HIV virus.

Virus reproduction cycle:

The lytic cycle is the term used to describe the reproduction cycle of every viruses known up to date

  • First, the virus particle attaches to a host cell
  • The particle releases its own genetic instructions in the host cell
  • The genetic materials that have been injected into the host cell recruits enzymes from the host cell’s
  • Type enzymes then make more parts for more new viruses particles
  • The new particles gather the parts into new viruses
  • The new viruses then leave the host cell which leads the host cell the die
  • Finally, new viruses are able to infect the host cells
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How are viruses treated?

The role of vaccines in treating viruses is to develop immunity by copying the infections and produce antibodies but without causing any illness in the body like germs and viruses do. Instead, the vaccine help the body immune system to develop to same response it does to a real infection. Once the immune system can produce its own anti bodies, it will be able to recognise diseases the body has been vaccinated against and fight them off.

For example flu vaccines are made using three ...

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