1. Describe 2 methods of viral infection
2. How can a virus be helpful to its host?
Please this is very urgent, I have finished everything else but these r my last 2 questions that I don't know! Please help! Thanks:)
http://www.webmd.com/a-to-z-guides/bacterial-and-viral-infections
http://microbemagic.ucc.ie/about_microbes/good_viruses.html
1. Two common methods of viral infection are:
a) Direct cell entry: Some viruses have surface proteins that bind specifically to receptors on host cell surfaces. When the virus encounters a suitable host cell, these proteins allow the virus to attach and enter the cell. Once inside, the virus uses the host cell's machinery to replicate itself, produce new viral particles, and spread to other cells.
b) Membrane fusion: Certain viruses, such as the influenza virus, induce fusion of their viral envelope with the host cell membrane. This fusion allows the viral genetic material to enter the host cell and initiate infection. After entry, the virus takes control of the host cell's machinery to replicate and produce more viruses.
To understand the methods of viral infection, researchers often employ laboratory techniques such as cell culture assays, genetic sequencing, electron microscopy, and other molecular biology methods. These techniques involve growing cells in a controlled environment, infecting them with viruses, and studying the infected cells to understand the mechanisms of viral entry and replication.
2. Viruses are generally considered harmful and can cause various diseases in their hosts. However, there are instances where viruses can be helpful to their hosts. Some ways in which viruses can assist their hosts include:
a) Gene transfer: Viruses can transfer genetic material between organisms. This process, known as horizontal gene transfer, can result in the acquisition of new genes or traits that may be beneficial to the host. For example, retroviruses have been found to play a role in the evolution of placental mammals by introducing genes essential for reproductive functions.
b) Immune system training: Viruses can help train the immune system of their hosts. When a host is infected with a virus, the immune system recognizes the viral antigens and mounts an immune response. This process facilitates the production of antibodies and stimulates the immune system to build a memory against the specific virus. This memory response can help the host's immune system to respond more effectively to future infections by the same or related viruses.
Research in virology and related fields such as immunology and genetics has contributed to our understanding of the benefits viruses can offer to their hosts. Scientists study virus-host interactions using various experimental methods, including animal models, cell culture systems, genomic analysis, and immunological assays. Through these investigations, they have discovered how certain viruses can have positive impacts on their hosts in specific contexts.