test 2 ch 17 Flashcards
a single-celled organism that lacks a nucleus and membrane-bounded organelles
prokaryote
the two domains of prokaryotes
bacteria and archaea
how have prokaryotic organisms influenced the earth
contributed O2 to earth’s atmosphere, created a protective ozone layer, and paved the way for aerobic respiration
explain the controversy around the term prokaryote
the word prokaryote falsely implies a close evolutionary relationship between bacteria and archaea, despite DNA evidence indicating that archaea is more closely related to eukaryotes; another reason is because prokaryotes are paraphyletic (don’t form a single, complete clade)
t or f: archaea is more closely related to eukaryotes
true
size of prokaryotes
1-10 um
features bacteria and archaea have in common
size, prokaryotic, circular chromosome, unicellular, some can fix nitrogen or grow at temp. above 80C
differences between archaea and bacteria
cell wall (archaea wall is protein), membrane (archaea based on nonfatty acids lipids), some bacteria use chlorophyll but archaea cannot, bacteria cant generate methane, archaea insensitive to streptomycin and genes may contain introns but bacterial genes dont
the region where a prokaryotic cells DNA is located, along with some RNA and a few proteins
nucleoid region
circles of DNA apart from the chromosome
plasmid
these genes may encode the proteins necessary to copy the plasmid and transfer it to another cell or other genes may provide the ability to resist an antibiotic or toxin, cause disease, or alter the cells metabolism
plasmid genes
structures that use the info in RNA to assemble proteins
ribosomes
a rigid barrier that surrounds the cells of most bacteria and archaea
cell wall
a complex polysaccharide that only occur in cell walls of bacteria, antibiotics take advantage of this by interfering with the cells synthesis
peptidoglycan
sometimes called capsule or slime layer, it is a sticky layer of proteins or polysaccharides that may surround the cell wall; helps with attachment to surfaces, resistance to drying, and protection from immune system cells (under microscope appears as the area that’s kinda clear)
glycocalyx
short-hairlike projections made of proteins that enable cells to adhere to objects
pili
when cells move toward or away from an external stimulus such as food, toxins, oxygen or light
taxis
dormant, thick-walled structures that can survive harsh conditions (examples clostridium botulinum)
endospores
what does the cell wall of a gram-positive cell look like and what color does it show
it is shown as purple and the cell wall looks like a sandwich with lettuce on top
what does the cell wall of a gram-negative cell look like and what color does it show
it is pink and it looks like a sandwich with lettuce in the middle
staphylo-
clusters (think of congestion = staph infection = clusters)
strepto-
chain like structure (think of feeling like your throat is chained shut during strept thoat)
organism that acquire carbon through consumption of other organisms
heterotroph
organism that acquires carbon from inorganic sources like CO2
autotroph
organism that derives energy from the sun
phototroph
organism that derives energy from chemicals
chemotroph
organism that uses O2 to produce ATP
aerobe
an organism that can produce ATP without O2
anaerobe
for these types of anaerobes, O2 is toxic and they live in habitats that lack it
obligate anaerobes
for these types of aerobes, they require O2 for generating ATP in cellular respiration
fucultative aerobes
anaerobes that include the intestinal microbes, (E. coli and salmonella), that can live with or without O2
facultative anaerobes
anaerobes that include the intestinal microbes, (E. coli and salmonella), that can live with or without O2
facultative anaerobes
ways biologists classify prokaryotes
DNA sequencing
t or f: molecular data can help construct evolutionary relationships
true
passage of DNA from one generation to the next; cell division
vertical gene transfer
when a cell receives DNA from another cell that is not its ancestor
horizontal gene transfer
