Structure: The protein shell of the virus is called capsid, and the genetic material is mostly RNA or DNA. Molecules are collectively called core-shell However, taking HIV as an example, the virus surface is also wrapped with cell membrane and spiny structure similar to cell membrane, which together with capsid * * * determines the specificity of the virus. There are some enzymes, such as reverse transcriptase.
Virus is a cell-free life form, which consists of a long nucleic acid chain and a protein shell. Viruses do not have their own metabolic mechanism and enzyme system. So when the virus leaves the host cell, it becomes a chemical substance that has no life activity and cannot reproduce on its own.
Once it enters the host cell, it can use the material and energy in the cell and the ability of replication, transcription and translation to produce a new generation of viruses like it according to the genetic information contained in its own nucleic acid.
Extended data
Classification and application of viruses
Viruses are not only divided into plant viruses, animal viruses and bacterial viruses. Structurally, it is also divided into single-stranded RNA virus, double-stranded RNA virus, single-stranded DNA virus and double-stranded DNA virus. The life process of virus can be roughly divided into five steps: adsorption, injection (genetic material), synthesis (reverse transcription/integration into host cell DNA), assembly (using host cell to transcribe RNA and translate protein for reassembly) and release.
Because the virus will narrow the distance between cells, it is easy for cells to fuse to form multinucleated cells and then crack. The application of this virus is as follows:
1, the inactivated virus is a vaccine.
2. As a carrier of genetic engineering
3. Induction of cell fusion in cell engineering (inactivation of virus)