What is it called when a virus attaches to a host cell?
Viral entry is the earliest stage of infection in the viral life cycle, as the virus comes into contact with the host cell and introduces viral material into the cell.
What happens when a virus attaches to a host cell?
When it comes into contact with a host cell, a virus can insert its genetic material into its host, literally taking over the host’s functions. An infected cell produces more viral protein and genetic material instead of its usual products.
What a drop of blood can tell?
A drop of blood can tell you a lot about a person—whether he or she might have heart disease, an STD or diabetes, for instance, or tell-tale signs of certain cancers.
How does a virus attach to the host cell?
This protein attaches the virus to the membrane of the host cell. Some enveloped viruses can dissolve right through the cell membrane of the host because both the virus envelope and the cell membrane are made of lipids. Those viruses that do not enter the cell must inject their contents (genetic instructions, enzymes) into the host cell.
How does a virus with no viral envelope enter the cell?
Viruses with no viral envelope enter the cell through endocytosis; they are ingested by the host cell through the cell membrane.
How are viruses found in the human body?
Viruses lie around our environment all of the time just waiting for a host cell to come along. They can enter us through the nose, mouth or breaks in the skin (see How the Immune System Works for details). Once inside, they find a host cell to infect. For example, cold and flu viruses will attack cells…
How does a virus enter the plasma membrane?
Viral entry pathways. Virus can fuse either directly to the plasma membrane (receptor-mediated fusion) or after being swallowed into an endosome. Which of these routes is followed depends on the type of virus. In fusion with the plasma membrane, the virus binds to a protein in the cell membrane.
How is a virus specific to its host?
Viruses can infect only certain species of hosts and only certain cells within that host. Specific host cells that a virus must occupy and use to replicate are called permissive . In most cases, the molecular basis for this specificity is due to a particular surface molecule known as the viral receptor on the host cell surface.
How is the attachment of a virus achieved?
Attachment is achieved when specific proteins on the viral capsid or viral envelope bind to specific proteins called to receptor proteins receptors on the cell membrane of the target cell.
Where do viral receptors attach to the host cell?
In viruses with a viral envelope, viral receptors attach to the receptors on the surface of the cell and secondary receptors may be present to initiate the puncture of the membrane or fusion with the host cell.
How does a virus stick to the cell membrane?
Viruses initially stick to cell membranes through interactions unrelated to fusion proteins. The virus surfs along the fluid surface of the cell and eventually the viral fusion proteins bind to receptor molecules on the cell membrane (4). If only binding occurred, the two membranes would remain distinct.