prokaryotes Flashcards
who discovered archaea?
Carl Woese
what was the third new domain that Woese discovered? and what kingdoms did it comprise.
monera, split into eubacteria and archaea
what is an endosymbiont?
an organism that lives in the body of another
what are the 2 classifications of bacteria?
gram-positive, gram-negative
what are 2 characteristics of gram-positive bacteria?
thicker walls/peptidoglycan layers, stain purple (positive)
what’s the first amino acid in all archaea and eukaryote proteins?
methionine
what’s the first amino acid in all bacteria proteins?
formylmethionine
what is the DNA organization of archaea?
circular with histones
what is the DNA organization of bacteria?
circular (w/o histones)
what is the DNA organization of eukaryotes?
circular with histones
bacteria that require oxygen are called
obligate aerobes
what are facultative aerobes?
bacteria that can perform aerobic respiration when oxygen is present, and perform anaerobic respiration/fermentation when it is not
what are obligate anaerobes?
bacteria that cannot live where oxygen is present
list the subgroups of the phylum euryarchaeota
methanogens, halophiles, thermophiles (lithotrophs), psychrophiles
what is a requirement for methanogens’ environment?
anoxic/low oxygen
where can methanogens be found?
wetlands, digestive tracts
how do methanogens generate energy?
methanogenesis
where can halophiles be found?
environments with high salt concentration
dead sea, salt-preserved foods
where do halophiles get most their energy from?
food + air, some can use light
where can thermophiles be found?
extreme environments
hot springs, hydrothermal vents on ocean floor
what is said to be oldest/least evolved branch of the archaea phylogenetic tree?
thermophilic archaea
what is the final electron acceptor for thermophiles (archaea?)
sulfur
lithotropic means
able to oxidize sulfur and create sulfuric acid as a form of energy
where can lithotrophs be found?
low pH, extremely acidic environments
where can psychrophiles be found?
cold environments
arctic oceans
how many chromosomes do bacteria have?
1
what are the 2 forms in which bacteria carry DNA?
1 nucleoid: single loop of DNA
multiple plasmids: smaller loops of DNA, are not essential for cellular functions
on the outside of bacteria is… (name structures)
small hairlike pili
1+ flagella