Studied by 13 people
positive phototaxis
a species moves towards light
negative phototaxis
a species moves away from light
endospore
a temporary state of a bacteria when it is dormant. helps survive harsh environment
binary fission
an asexual mean of reproduction. DNA copies itself, sticks to opposite sides of the cell wall, and then cell splits into two
phototroph
a species that gains energy from photosynthesis/light
chemotroph
a species that gains energy by chemical from environment
autotroph
a species that gets carbon from inorganics
heterotroph
a species that gains carbon organically (e.g. from eating someone)
obligate aerobe
a species that NEEDS oxygen to survive
obligate anaerobe
a species that CANNOT have oxygen (oxygen is poisonous)
facultative anaerobe
a species that can survive with or without oxygen
bioremediation
organisms will break down pollutants to help the environment
two main branches of prokaryotic evolution
bacteria and archaea
components of prokaryotic cell wall
bacteria has peptidoglycan and sometimes lipopolysaccharide, archaea do not have pg but have polysaccharides and proteins
gram-pos vs. gram-neg bacteria cell wall
pos: thick pg layer over plasma membrane
neg: thin pg layer between outer and plasma membrane, outer membrane has lipopolysaccharide
prokaryote cell wall function
keeps shape, physical protection, prevents bursting in a hypotonic environment
why is gram-neg more threatening than gram-pos?
better defends against host, when cell dies the toxic cell wall is revealed
how does penicillin inhibit prokaryotic growth?
inhibits cross-link formation which limits cell wall function and reproduction
capsule and its function
a thick, sticky outer layer created by prokaryotes to prevent dehydration, resist host attacks, and keep stick/clump cells together
fimbriae and its function
hair-like structures that do similar things as slime layer
major differences between prokaryotes and eukaryotes
prokaryotes have no organization and internal membrane, they have simpler and smaller DNA, has plasmids
plasmids and its function
a different set of DNA (may have increased antibacterial resistance) and can be donated to other cells
how do erythromycin and tetracycline inhibit bacteria growth?
erythromycin: inhibits protein synthesis
tetracycline: interferes with protein synthesis or destroys membrane
horizontal gene transfer
one cell gives its DNA to a cell of a different species
transformation (gene transfer)
recipient cell takes genes from surrounding environment. donor cell is usually dead
transduction (gene transfer)
virus takes donor cell DNA and puts it in the recipient cell
conjugation (gene transfer)
two cells directly connect and plasmid moves donor DNA to recipient cell
photoautotroph
photosynthetic organisms that synthesize nutrition from CO2 (such as plants and algae)
chemoautotroph
only need CO2 and synthesize inorganics (hydrogen sulfide, ammonia, iron)
photoheterotroph
use light for energy but need CO2 from organic source (carbs and fatty acids) (not common)
chemoheterotroph
consume organics for carbon and energy (humans)
metabolic cooperation advantages
different cells doing different task increases efficiency and productivity
biofilm
the sticky slime that keeps colonies of cells together
extreme thermophile
thrives at high temperatures
extreme halophile
thrives in high salt concentrations
extreme methanogen
microorganisms that produce methane in low oxygen environments
symbiosis
interaction between two organisms in close proximity
mutualism
both species benefit
parasitism
one species benefits while the other is harmed
commensialism
one species benefit while the other isn’t affected
opportunistic pathogen
only hurts host if their immune system is down
endotoxin
when a cell dies, it releases toxins that were inside the cell (gram-neg, lipopolysacchrides)
exotoxin
proteins that are secreted hurts host
cause of increases antibiotic resistance
being prescribed and taken too often/when not necessary
Note
Flashcard