THE HUMAN IMMUNE SYSTEM
IMMUNE RESPONSE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
They are too small.
|
|
|
A virus is a living organism.
|
|
|
They need a host to reproduce.
|
|
|
Viruses do not have DNA/genetic material.
|
Detailed explanation-1: -Viruses are considered as something between living and non-living because they do not grow or reproduce by themselves. This makes them non-living. However, when a virus enters a living cell of an organism, it obtains energy from the host cell and starts reproducing.
Detailed explanation-2: -Viruses are not made out of cells, they can’t keep themselves in a stable state, they don’t grow, and they can’t make their own energy. Even though they definitely replicate and adapt to their environment, viruses are more like androids than real living organisms.
Detailed explanation-3: -Living things use energy. 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-4: -The authors concluded that viruses originated in ‘proto-virocells’ that were cellular in nature and they implied that viruses and modern bacteria evolved from common ancestors. They further claim that this means that viruses are indeed living organisms.