Outside of living cells, viruses are Select one: a. using cilia to move to the next host. b. replicating by binary fission. c. scavenging glucose. d. metabolically inert. e. gaining ATP from the mitochondria.
The correct answer and explanation is:
Correct answer: d. metabolically inert
Viruses are unique infectious agents that differ significantly from living organisms. Outside of living cells, viruses are metabolically inert. This means they do not carry out any metabolic activities such as energy production, nutrient consumption, or waste excretion. Unlike bacteria and other living cells, viruses lack the necessary cellular machinery to perform these functions independently.
A virus consists primarily of genetic material—either DNA or RNA—encased in a protein coat known as a capsid. Some viruses may also have an outer lipid envelope. However, they do not contain ribosomes, mitochondria, or other organelles required for metabolism or reproduction. As a result, viruses are entirely dependent on the host cell’s machinery to carry out vital processes.
When a virus enters a suitable host cell, it hijacks the host’s metabolic and replication systems to produce copies of itself. Until then, it remains inert and unable to perform any life processes. It neither grows nor divides outside of the host. This is why viruses are considered obligate intracellular parasites. They are only active and capable of reproduction once they are inside a living cell.
The incorrect options highlight misunderstandings about viral behavior:
- a. Viruses do not have cilia or any structure for independent movement.
- b. Binary fission is a method of asexual reproduction used by bacteria, not viruses.
- c. Scavenging glucose implies metabolism, which viruses lack outside a host.
- e. Viruses do not have mitochondria and cannot generate or gain ATP on their own.
In summary, viruses remain inactive and inert when outside of a host cell, incapable of carrying out any life-sustaining activities. Their survival and replication depend entirely on infecting and exploiting the machinery of living cells.