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Bacteria and Viruses


unicellular organism lacking a nucleus


rod-shaped prokaryote


spherical prokaryote


spiral or corkscrew-shaped prokaryote


organism that must take in organic molecules for both energy and carbon


organism that is photosynthetic but needs organic compounds as a carbon source


organism that uses energy from sunlight to convert carbon dioxide and water to carbon compounds


organism that makes organic carbon molecules from carbon dioxide using energy from chemical reactions

obligate aerobe

organism that requires a constant supply of oxygen in order to live

obligate anaerobe

organism that cannot live in the presence of oxygen

facultative anaerobe

organism that can survive with or without oxygen

binary fission

type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells


form of sexual reproduction in which paramecia and some prokaryotes exchange genetic information


type of spore formed when a bacterium produces a thick internal wall that encloses its DNA and a portion of its cytoplasm

nitrogen fixation

process of converting nitrogen gas into ammonia


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


outer protein coat of a virus


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


the viral DNA that is embedded in the host cell's DNA


virus that contains RNA as its genetic information


disease-causing agent


a preparation of weakened or killed pathogens


compound that blocks the growth and reproduction of bacteria


single-stranded RNA molecule that has no surrounding capsids


infectious particle made up of protein rather than RNA or DNA

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