AP BIOLOGY

Detailed explanation-1: -Viruses cannot reproduce outside a living cell because they lack the cellular organisation and independent machinery which is required for the reproduction and other metabolic activities. They can only multiply inside the living cell of host by using host’s cellular machinery.

Detailed explanation-2: -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-3: -Viruses are smaller than the bacteria. Viruses consists of a genetic material (DNA or RNA) as well as a protein coat. Viruses require the host cell to reproduce. They are inactive outside the host cell.

Detailed explanation-4: -Complete answer: All viruses are obligate parasites, i.e., they lack metabolic machinery of their own to generate energy or to synthesize proteins, hence they depend on the host cells to carry out these vital functions.

Detailed explanation-5: -So were they ever alive? Most biologists say no. 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.