Viruses can infect all types of cells including plant, animal, protozoa, fungi, and bacteria. Virus composition is unique and does not resemble a living cell because they only contain the necessary parts to enter and leave an infected cell. A virus is a minute parasite (10 to 100 times smaller than bacteria) that is unable to reproduce by itself; however, once it infects a vulnerable cell a virus can make the cell’s inner workings produce viruses on its behalf. Viruses typically have either RNA or DNA as their genetic composition. The nucleic acid can either be single stranded or double stranded. The complete communicable virus particle, a virion, is composed of nucleic acid and an outer shell of protein called a capsid and on occasion, a virus may have a membrane envelope. This envelope assists the virus to come in and out of the host cell. Even the simplest virus contains only enough RNA or DNA to encode a maximum of four proteins. The most complex virus; on the other hand, can encode anywhere to 100 to 200 proteins. The common cold and flu are examples of a virus at work. In most instances, rest, hydration, and reliance on a person’s own immune system to recover from these viral induced illnesses are recommended for recovery. Immunizations are also recommended for viral prevention.
Bacteria are living prokaryotic organisms and are unicellular. A bacterium is considered to be alive because it does not need a living cell to thrive. Bacterial cells utilize binary fission followed by replication of the bacterial chromosome. Bacteria can grow on non-living surfaces and resides in between cells, instead of inside a living cell, the only place amicable for viruses. They transfer genes from various cells by transformation, transduction, or conjugation. Small circular DNA molecules called plasmids, carry the bacterial chromosome during gene transfers. Strep throat is a common illness caused by bacteria. This, as well as all bacteria caused illnesses, can be...
Please join StudyMode to read the full document