EVERYDAY SCIENCE

Detailed explanation-1: -Outside of a host cell, viruses do not use any energy. They only become active when they come into contact with a host cell. Once activated, they use the host cell’s energy and tools to make more viruses. Because they do not use their own energy, some scientists do not consider them alive.

Detailed explanation-2: -Viruses are perfect parasites. It has been known for decades that once a virus gets inside a cell, it hijacks the cellular processes to produce virally encoded protein that will replicate the virus’s genetic material.

Detailed explanation-3: -But when a virus enters a cell (called a host after infection), it is far from inactive. It sheds its coat, bares its genes and induces the cell’s own replication machinery to reproduce the intruder’s DNA or RNA and manufacture more viral protein based on the instructions in the viral nucleic acid.

Detailed explanation-4: -A virus is a tiny, infectious particle that can reproduce only by infecting a host cell. Viruses “commandeer” the host cell and use its resources to make more viruses, basically reprogramming it to become a virus factory. Because they can’t reproduce by themselves (without a host), viruses are not considered living.

Detailed explanation-5: -Endocytosis: The host cell takes in the viral particle through the process of endocytosis, essentially engulfing the virus like it would a food particle.