Virology Flashcards
Explain steps of viral replication
Protein synthesis: During viral replication, the virus hijacks the host cell’s machinery to produce viral proteins that are necessary for replication. The viral genome contains the instructions for making these proteins, which are translated by the host cell’s ribosomes.
Replication of genome - Differences between DNA & RNA viruses: The replication of viral genome differs between DNA and RNA viruses. DNA viruses replicate their genome by using the host cell’s DNA polymerase, while RNA viruses use their own RNA-dependent RNA polymerase to replicate their genome. RNA viruses also often have to encode their own RNA replicase due to the lack of this enzyme in host cells.
Virus assembly: Once the viral proteins and genome have been synthesized, they come together to form new viral particles. The process of virus assembly involves the proper folding and interaction of viral proteins, as well as the packaging of the viral genome into the new viral particles.
Budding & release: The final step of viral replication is the release of new viral particles from the host cell. Some viruses are released by budding, in which the viral particle pushes its way out of the host cell by taking a portion of the host cell’s membrane with it. Other viruses lyse, or break open, the host cell to release new viral particles. The method of release often depends on the type of virus and the host cell that it infects.
To be able to discuss individual characteristics of certain viruses
Herpes simplex virus
Varicella zoster virus
HIV
Herpes simplex virus (HSV):
HSV is a highly infectious virus that causes a wide range of diseases in humans, including oral and genital herpes. The virus is enveloped and contains a double-stranded DNA genome. There are two types of HSV: HSV-1 and HSV-2. HSV-1 typically causes oral herpes, while HSV-2 is associated with genital herpes. However, both types can cause both types of infections. The virus is highly contagious and can be transmitted through direct contact with infected skin or mucous membranes.
Varicella zoster virus (VZV):
VZV is a highly contagious virus that causes two distinct diseases: chickenpox and shingles. It is a member of the herpesvirus family and contains a double-stranded DNA genome. VZV is transmitted through direct contact with an infected person’s skin or through inhalation of virus-containing droplets. The virus is highly infectious and can be spread easily in crowded environments.
HIV:
HIV (human immunodeficiency virus) is a virus that attacks the immune system, specifically the CD4 cells, which are a type of white blood cell that help fight infections. HIV is an enveloped virus that contains a single-stranded RNA genome. The virus is primarily spread through sexual contact, sharing of needles, and from mother to child during pregnancy, childbirth, or breastfeeding. HIV can lead to the development of AIDS (acquired immunodeficiency syndrome), which is a condition characterized by severe immune system damage and an increased susceptibility to opportunistic infections and cancers. There is no cure for HIV, but antiretroviral therapy can help people living with HIV manage the virus and prevent the progression to AIDS.
