Is a virus alive or not?

Answer 1

No, they are classified as nonliving and most scientists agree with that designation. There has been an ongoing debate as to whether viruses are alive or not in the past, but it is currently the more accepted answer among virologists.

With the facts given below, see what you think:

All Living things:
-are composed of cells with a complex, organized structure
-actively maintain their complex structure and internal environment (homeostasis)
-respond to stimuli in their environment
-acquire and use materials and energy from their environment and convert them into new forms
-reproduce, using the molecular blueprint of DNA
-have the capacity to evolve

Viruses:
-are not made of cells and do not have cells
-cannot accomplish the basic tasks of living cells
-have no ribosomes to make protein
-have no cytoplasm
-cannot acquire energy or steal the host's energy*
-cannot grow or reproduce by themselves or with other viruses
-do not respond to stimuli
-cannot maintain a stable internal environment
-can evolve

*However, they do make use of the energy of the host in that they take over command of the host's cell into which the virus put the genetic material when it invaded. This makes the cell a "virus building factory" using the host energy and materials to do the work of viral replication. See the question about the lytic cycle in the related questions for more about how viruses reproduce.

Answer 2

Viruses are technically not living cells, because

-- they don't use energy to grow or reproduce

-- they cannot reproduce on their own: they need a "host" cell that will turn their genetic material into more viruses

-- they don't eat or produce waste.

Answer 3

Viruses are not considered to be living organisms as they cannot reproduce on their own, they need a host cell.