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particle made up of nucleic acid, protein, and in some cases lipids that can replicate only by infecting living cells


the outer covering of protein surrounding the nucleic acid of a virus


a virus that infects bacteria

Lytic infection

process in which a virus enters a cell, makes a copy of itself, and causes the cell to burst

Lysogenic infection

process by which a virus embeds its DNA into the DNA of the host cell and is replicated along with the host cell's DNA




any of a group of viruses that contain two single-strand linear RNA molecules per virion and reverse transcriptase (RNA to DNA)


a unicellular organism having cells lacking membrane-bound nuclei


aerobic rod-shaped spore-producing bacterium


any spherical or nearly spherical bacteria


any flagellated aerobic bacteria having a spirally twisted rodlike form

Binary fission

a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size


a small asexual spore that develops inside the cell of some bacteria and algae


the act of making or becoming a single unit


any disease-producing agent (especially a virus or bacterium or other microorganism)


immunogen consisting of a suspension of weakened or dead pathogenic cells injected in order to stimulate the production of antibodies


a chemical substance derivable from a mold or bacterium that kills microorganisms and cures infections

Emerging disease

a disease that is caused by new or reappearing infectious agents that typically exist in animal populations


(microbiology) an infectious protein particle similar to a virus but lacking nucleic acid

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