What are the two 2 main mechanisms for the entry of enveloped viruses into their host cells?
Enveloped viruses (i.e., viruses with a lipid envelope) use a two-step procedure to release their genetic material into the cell: (i) they first bind to specific surface receptors of the target cell membrane and then, (ii) they fuse the viral and cell membranes.
Pathogenic mechanisms of viral disease include (1) implantation of virus at the portal of entry, (2) local replication, (3) spread to target organs (disease sites), and (4) spread to sites of shedding of virus into the environment.
What are the two types of mechanisms it uses to infect host cells?
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.
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 do enveloped viruses differ from Nonenveloped viruses?
These differences reflect different mechanisms of cell entry and different pathways of assembly and maturation. Enveloped viruses enter by membrane fusion, either from an internal compartment following an endocytic step, or at the cell surface. Non-enveloped viruses require some form of membrane “perforation”.
What is the difference in entry between enveloped and Nonenveloped animal viruses?
Enveloped viruses can fuse directly with the plasma membrane, releasing the capsid directly into the cytosol, whilst non-enveloped viruses disrupt or form pore(s) in the plasma membrane to gain entry.
Why are some viruses more pathogenic than others?
In the previous section, we explained that some pathogens are more virulent than others. This is due to the unique virulence factors produced by individual pathogens, which determine the extent and severity of disease they may cause.
What is host mechanism?
Host defenses that protect against infection include. Natural barriers (eg, skin, mucous membranes) Nonspecific immune responses (eg, phagocytic cells [neutrophils, macrophages] and their products) Specific immune responses (eg, antibodies, lymphocytes)
Why are most viruses highly specific to the cells they infect?
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.
How do all viruses differ from bacteria group of answer choices?
Viruses are tinier: the largest of them are smaller than the smallest bacteria. All they have is a protein coat and a core of genetic material, either RNA or DNA. Unlike bacteria, viruses can’t survive without a host. They can only reproduce by attaching themselves to cells.