Viruses That In The Form Are RNA
Viruses that are essentially RNA, in the host cell will undergo replication to form new RNA-RNA. RNA also undergoes translation to form proteins for viral envelope. In the host cell, RNA and viral proteins construct themselves into new viruses.
mRNA also translates to form destructive enzymes that destroy cell membranes. Thus the host cell lysis (destroyed) and viruses - the virus comes out and is ready to infect new inning cells.
RETROVIRUS (Virus with RNA Core That Can Become a Mold to Form DNA Copies)
Unlike the two types of viruses above the retrovirus into cells with endocytosis, endocytosis is the entry of molecules into the cell by: the cell forms a bulge then the molecules in the swallow enter the cell. So by means of endocytosis, both the nucleus and capsid retroviruses enter the host cell.
In the host cell, RNA, retroviruses can make DNA copies (cDNA). This can happen because retroviruses have a reverse transcriptase enzyme, which is an enzyme that can make DNA copies of RNA. This ability is not possessed by organisms, and is only possessed by viruses.
This copy DNA is then integrated into the host DNA (in general animal cells) DNA then undergoes transcription to form RNA, both RNA which will become the core RNA of the virus, and mRNA that carries codons which will be translated into proteins and reverse transcriptase enzymes.
Furthermore the viral core RNAs, reverse transcriptase enzymes, and viral proteins self-construct to form new viruses. Retroviruses do not produce destructive enzymes, so new viruses are formed in the host cell out of the cell without destroying the cell membrane, ie with exocytosis, exocytosis is the opposite of endocytosis
Examples of retroviruses are HIV,
the virus that causes AIDS. HIV has an RNA nucleus, and in human cells the reverse transcriptase enzyme will make DNA copies of the HIV RNA.
As already mentioned that the way of reproduction of viruses varies. The following are 2 examples of virus reproduction. Namely reproduction in bacterial viruses (bacteriophages) and animal viruses.
Bacteriofage reproduction
Bacteriophage reproduction can occur through two cycles. Namely the lytic and lysogenic cycles, in the lytic cycle the attachment, penetration, replication and synthesis stages and maturation take place quickly. Virus particles can be infected cells by breaking the cells so that the host cell dies (lysis).
In the lysogenic cycle, DNA / RNA of the virus is inserted into the host cell's romosome. Chromosomes that are inserted DNA / RNA viruses will make a replication, this happens continuously during cell division so that the genetic material of the virus will be passed on to the cells of the host cells, so in the lysogenic cycle, the virus infection enters latency, meaning that the host cell does not break (dead).
Animal Virus Reproduction
One type of animal virus is a virus that has a virus cover, at the attachment stage, the virus cover is attached and fuses (joins) with the host cell membrane.
At the stage of penetration of viral DNA and capsid separately, then at the stage of replication and synthesis DNA replication occurs Virus, capsid and virus cover. At the stage of maturation new virus particles are formed, at this stage also the virus cover is formed on new virus particles. At the release stage, new viruses come out of the host cell and are ready to infect other cells.