NEET BIOLOGY

Detailed explanation-1: -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-2: -Because they can’t reproduce by themselves (without a host), viruses are not considered living. Nor do viruses have cells: they’re very small, much smaller than the cells of living things, and are basically just packages of nucleic acid and protein.

Detailed explanation-3: -They do not contain any cell organelle like mitochondria, ribosome etc. Viruses are alive only until they are inside their host cell. They are considered to behave dead when outside the host cell. Hence, Viruses are an exception to cell theory.

Detailed explanation-4: -They do not possess any similarity with the other cells. They do not have any organelles and fail to perform metabolic activities. Therefore, viruses are not placed in any domains.

Detailed explanation-5: -Fundamental to the argument that viruses are not alive is the suggestion that metabolism and self-sustaining replication are key definitions of life. Viruses are not able to replicate without the metabolic machinery of the cell. No organism is entirely self-supporting, however – life is absolutely interdependent.