JSmart 050315 Mod 4 Assignment
Module 04 Homework Assignment
Use the information presented in this module along with additional outside research to answer the questions:
1 Discuss the two methods of viral replication.
The two methods of viral replication are done in animal viruses. The first method deals with DNA viruses and the second is RNA viruses. In the DNA virus, the viral DNA enters the nucleus of the host cell. Than it is transcribed into mRNA and leaves the nucleus into the cytoplasm. The early mRNA then translates into early viral proteins. The early viral proteins deal with the replication of viral DNA, they are then transported back into the nucleus. Once in the nucleus the proteins become involved in making multiply copies of the viral DNA, using host DNA polymerase. The copies of viral genome act as a template for transcription into late mRNA, which leaves the nucleus for translation into late viral proteins in the cytoplasm. The late proteins are structural proteins that are transported back into the nucleus for the next stage of replication (VanMeter, 2010). RNA viruses cannot be transcribed the same way as DNA viruses. RNA viruses must provide their own polymerase if transcription is necessary. If dsRNA happens, one strand is first transcribed by viral polymerase into mRNA. Three separate actions have to occur for mRNA to occur in ssRNA viruses. The first is an ssRNA with a positive-sense configuration can be used directly as mRNA. The second is ssRNA with a negative-sense configuration must first be transcribed into positive-sense strand by viral polymerase and then can be used as mRNA. The third is retroviruses. These viruses have a positive-sense ssRNA that is made into negative-sense ssDNA, using viral reverse transcription present in the nucleocapsid. This is followed by dsDNA, which enters the nucleus and becomes integrated into host DNS. The viral DNA is then transcribed by the host polymerase into mRNA (VanMeter, 2010). In all three of these different processes,
Use the information presented in this module along with additional outside research to answer the questions:
1 Discuss the two methods of viral replication.
The two methods of viral replication are done in animal viruses. The first method deals with DNA viruses and the second is RNA viruses. In the DNA virus, the viral DNA enters the nucleus of the host cell. Than it is transcribed into mRNA and leaves the nucleus into the cytoplasm. The early mRNA then translates into early viral proteins. The early viral proteins deal with the replication of viral DNA, they are then transported back into the nucleus. Once in the nucleus the proteins become involved in making multiply copies of the viral DNA, using host DNA polymerase. The copies of viral genome act as a template for transcription into late mRNA, which leaves the nucleus for translation into late viral proteins in the cytoplasm. The late proteins are structural proteins that are transported back into the nucleus for the next stage of replication (VanMeter, 2010). RNA viruses cannot be transcribed the same way as DNA viruses. RNA viruses must provide their own polymerase if transcription is necessary. If dsRNA happens, one strand is first transcribed by viral polymerase into mRNA. Three separate actions have to occur for mRNA to occur in ssRNA viruses. The first is an ssRNA with a positive-sense configuration can be used directly as mRNA. The second is ssRNA with a negative-sense configuration must first be transcribed into positive-sense strand by viral polymerase and then can be used as mRNA. The third is retroviruses. These viruses have a positive-sense ssRNA that is made into negative-sense ssDNA, using viral reverse transcription present in the nucleocapsid. This is followed by dsDNA, which enters the nucleus and becomes integrated into host DNS. The viral DNA is then transcribed by the host polymerase into mRNA (VanMeter, 2010). In all three of these different processes,