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27 terms

Chapter 19

Bacteria and Viruses
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prokaryote
unicellular organism lacking a nucleus
bacillus
rod-shaped prokaryote
coccus
spherical prokaryote
spirillum
spiral or corkscrew-shaped prokaryote
chemoheterotroph
organism that must take in organic molecules for both energy and carbon
photoheterotroph
organism that is photosynthetic but needs organic compounds as a carbon source
photoautotroph
organism that uses energy from sunlight to convert carbon dioxide and water to carbon compounds
chemoautotroph
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
conjugation
form of sexual reproduction in which paramecia and some prokaryotes exchange genetic information
endospore
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
virus
particle made up of nucleic acid, protein, and in some cases lipids that can replicate only by infecting living cells
capsid
outer protein coat of a virus
bacteriophage
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
prophage
the viral DNA that is embedded in the host cell's DNA
retrovirus
virus that contains RNA as its genetic information
pathogen
disease-causing agent
vaccine
a preparation of weakened or killed pathogens
antibiotic
compound that blocks the growth and reproduction of bacteria
viroid
single-stranded RNA molecule that has no surrounding capsids
prion
infectious particle made up of protein rather than RNA or DNA