chapter 27, quiz 1

bio 109 umkc

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