A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope. The specificity of this interaction determines the host—and the cells within the host—that can be infected by a particular virus.
How is a virus specific for a particular host cell?
Viruses can infect only certain species of hosts and only certain cells within that host. The molecular basis for this specificity is that a particular surface molecule, known as the viral receptor, must be found on the host cell surface for the virus to attach.
Are viruses specific to the host it infects?
Different Hosts and Their Viruses
As you’ve learned, viruses are often very specific as to which hosts and which cells within the host they will infect. This feature of a virus makes it specific to one or a few species of life on Earth.
Which structure allows a virus to recognize and attach to receptors on the host cell?
Attachment. A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope. The specificity of this interaction determines the host—and the cells within the host—that can be infected by a particular virus.
How does a virus use a host cell to replicate itself?
Viruses cannot reproduce on their own. Instead, viruses replicate by infecting a host cell (such as humans, other animals, plants or bacteria), hijacking the host’s biological machinery and turning the host cell into a virus-producing factory.
How does a virus take over a host cell 5 steps?
- Viral replication involves six steps: attachment, penetration, uncoating, replication, assembly, and release.
- During attachment and penetration, the virus attaches itself to a host cell and injects its genetic material into it.
What is the main way that viruses replicate?
There are two processes used by viruses to replicate: the lytic cycle and lysogenic cycle. Some viruses reproduce using both methods, while others only use the lytic cycle. In the lytic cycle, the virus attaches to the host cell and injects its DNA.
How do viruses mutate?
As a virus replicates, its genes undergo random “copying errors” (i.e. genetic mutations). Over time, these genetic copying errors can, among other changes to the virus, lead to alterations in the virus’ surface proteins or antigens. Our immune system uses these antigens to recognize and fight the virus.
What structure allows a virus to attach to a cell?
Overview. Prior to entry, a virus must attach to a host cell. Attachment is achieved when specific proteins on the viral capsid or viral envelope bind to specific proteins called receptor proteins on the cell membrane of the target cell.
Why are viruses not placed in the five kingdoms?
Viruses are microscopic organisms that are known to be the connecting link between living and non-living. These were not placed under the five-kingdom classification since they are neither living nor dead. Hence, they form their own group. Viruses are devoid of cells and cell organelles.
How does the structure of a virus relate to its function?
The simplest virions consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.
What do viruses depend on for their reproduction?
Viruses depend on the host cells that they infect to reproduce. When found outside of host cells, viruses exist as a protein coat or capsid, sometimes enclosed within a membrane. The capsid encloses either DNA or RNA which codes for the virus elements.
Why can’t viruses reproduce on their own?
A virus cannot replicate alone. Viruses must infect cells and use components of the host cell to make copies of themselves. Often, they kill the host cell in the process, and cause damage to the host organism. Viruses have been found everywhere on Earth.
Do all viruses replicate the same way?
As viruses are obligate intracellular pathogens they cannot replicate without the machinery and metabolism of a host cell. Although the replicative life cycle of viruses differs greatly between species and category of virus, there are six basic stages that are essential for viral replication.