Question

How is viral genetic material inserted into animal cells?

Answer 1

Hint: Viruses are infectious agents that take over the cell machinery to reproduce. They do not belong to either cell type, prokaryotes, or eukaryotes. They are not cells but they do have a genetic material (RNA or DNA). A protective covering called the capsid encloses the viral genetic material. Some viruses also have a covering of lipids called an envelope. They, however, require a host to survive and reproduce. Therefore, infect bacteria (bacteriophages), animals (animal viruses), and plants (plant viruses).

Complete answer:
-Viruses can insert their genetic material into the host cell in three different ways- direct injection, membrane fusion, and endocytosis. Enveloped animal viruses enter the body via membrane fusion. -Non-enveloped animal viruses (naked viruses) enter their host by endocytosis.
-The animal viruses recognize and bind to the receptors on the host (animal) cell membrane. The capsids of the viruses have certain proteins that recognize the receptor. This is the first step of infection.
Direct injection of the genetic material occurs usually in case of bacteriophages infection. The virus recognizes the receptor on the host cell membrane. The virus does not enter the cell only injects its genetic material inside the cell.
-The membrane fusion is when the enveloped virus will attach to the cell membrane of the host. Both membranes have the same composition. Both animal and host membranes fuse. The virus capsid enters and breaks open. The genetic material is released into the cell.
-Non-enveloped can enter the cell through receptor-mediated endocytosis. This is achieved by the capsid proteins binding to the host membrane. The virus tricks the host membrane to recognize the virus as a component the cell needs to engulf. The virus then enters the cell as a whole.

Note: The enveloped virus gets its envelope from the host itself. Therefore their membrane composition is the same. Inside the host cell, the virus is safe from the immune system of the host. After the virus divides inside the host, the host cell breaks open and the progeny leaves. Before leaving the viruses (progeny) will acquire the host membrane. Once outside the host cell, it is now safe from the host immune system. It can now infect other cells.