viruses. All viruses are obligate parasites; that is, they lack metabolic machinery of their own to generate energy or to synthesize proteins, so they depend on host cells to carry out these vital functions.
https://www.britannica.com › science
Obligate parasite - Encyclopedia Britannica
Encyclopedia Britannica | Britannica
Explore the fact-checked online encyclopedia from Encyclopaedia Britannica with hundreds of thousands of objective articles, biographies, videos, and images from experts.
https://www.britannica.com
