How do viruses differ from bacteria in the way it causes infections?
Viruses are much smaller than bacteria, ranging in size from 10 to 300 nanometers. Bacteria, on the other hand, are typically 1-10 micrometers in size. This difference in size means that viruses can easily penetrate cells and bacteria alike, while bacteria cannot enter cells as easily.
2. Structure:
Viruses lack the complex cellular structures found in bacteria. They consist of a protein coat that encloses a core of genetic material. For example, RNA or DNA. They do not have a cell membrane, cytoplasm or organelles.
3. Reproduction:
Viruses are not capable of reproducing without infecting a living cell. They can only reproduce inside the cells of living organisms, bacteria included. Once inside a host cell, the virus uses the host's machinery to replicate its genetic material and produce new viruses.
4. Infection Mechanism:
Viruses enter host cells through various mechanisms. Some viruses, like the influenza virus, bind to specific receptors on the surface of host cells and enter the cells through endocytosis. Others, such as the herpesvirus, may directly fuse with the cell membrane and inject their genetic material into the cells.
Bacteria, on the other hand, can invade and colonize host organisms in various ways. Some bacteria such as E.Coli, can enter the host through ingestion of contaminated food or water. Other bacteria, like Streptococcus pneumonia, can enter through inhalation of respiratory droplets.
5. Mode of action:
Once inside the host cells, viruses can cause infections in several ways. Some viruses, such as the measles virus, disrupt the host cells metabolism and cause cell death. Others, like HIV, insert their genetic material into the host cells' DNA and alter the cells' function. This, if not treated, may lead to long term health problems like cancer.
Bacteria also cause infections by various means. Some bacteria produce toxins that damage host tissues and cause symptoms of the disease. For instance, the bacterium Clostridium tetani produces the toxin tetanospasmin, which leads to muscle stiffness and spasms in tetanus. Other bacteria, such as Salmonella, cause infections through inflammation and tissue destruction.
6. Treatment:
The treatment for viral and bacterial infections differs due to their distinct nature. Some antiviral medications directly target the virus to stop its replication or prevent its entry into host cells. Antibiotics, on the other hand, are drugs that kill or inhibit the growth of bacteria, thereby helping the host to fight off the bacterial infection.
In conclusion, viruses and bacteria cause infections differently due to their variations in size, structure, reproduction mechanism, mode of action, and treatment methods.