Question

9. Discuss the arguments for and against the classification of viruses as living organisms.

10. You are growing Bacillus subtilis in nine 16,000-liter fermenters to produce enzyme for industrial use. The Bacillus cultures had been growing for 2 days when the cells in one of the fermenters lysed. Explain what happened in this fermenter.

11. You are chosen to be part of an international team gathering to choose the next infectious disease to be eliminated from the planet. Funding is limited. What are some factors you and your team should consider in deciding what disease to tackle?

Answer 1

Ans 9) There are various arguments that determine that the viruses are dead or alive. There are many reasons why viruses are considered to be semi-living as it has only some characteristics of life. They have no metabolism, no ribosomes, no plasma membrane etc. It has nucleic acid but it is not always active. The viruses that outside the host cell is not able to survive as they depend on the host for its function and regulation.

One of the biggest reasons why they can be considered as living is because they contain nucleic acid either in the form of DNA or RNA. The nucleic acid is the genetic material and forms part of the entire living organism. It can be considered as living as it contains genetic material.

One argument that shows that the virus is non-living is because they are not able to do anything without being dependent on the host organism. The virus lives and depends on the other living organisms or hosts and without them they become inert and are not able to multiply.

Ans 10) After two days of the Bacillus culture, the cells in one of the fermenters lysed because of the presence of bacteriophage. It led to lysis of the cells. The bacteriophage is a virus which is responsible for infecting and replicating using the bacteria as host. In this case, the virus used the bacteria as its host and led to the lysis.