Question

The fact that viruses can metabolize and reproduce only within the protoplasm of higher organisms indicates that they are also
A. Autotrophic
B. Heterotrophic
C. Autotrophic and heterotrophic
D. None of these

Answer 1

Hint: According to the availability of carbon source, organisms are divided into two groups – autotrophic and heterotrophic. Autotrophic organisms are those who can make their own food and heterotrophic organisms are those who are depending upon autotrophs for their food. The virus can do their metabolism and reproduction only in the host cell.

Complete answer: Virus can be defined as a protein molecule that has lived in the host body and without a host, it is a dead substance.
1. Autotrophic animals produce their foods in the presence of sunlight.
2. Viruses do not exhibit any kind of metabolism out of the host cell as they can only be alive inside a host cell. They do not have a life outside a host cell.
3. Viruses cannot produce their own food, that is they are not autotrophic.
So, option A. and C. are incorrect.
4. Viruses use the digestive enzymes of their host for their own metabolism process. By using the digestive enzymes they oxidize the organic materials and thus they exhibit their extracellular digestion.
5. So we can conclude that viruses are heterotrophic in nature.

Hence, here option B. Heterotrophic is the correct answer.

Note: DNA or RNA is the genetic material of the virus. Most organisms generate and store energy in the form of adenosine triphosphate (ATP) but the viruses cannot generate or store energy in the form of ATP. The viruses derive energy and metabolic products from the host cell only.