Ch. 24 - Prokaryotes Flashcards
Prokaryotes
An informal term for single called organisms in domains bacteria and archaea
When was life created
About 3.5 bill years ago
When did eukaryotes appear?
1.8 years ago
Four stages to produce life
- Abiotic synthesis of small organic molecules
- Joining the small molecule into macromolecules
- Packaging these molecules into protocells
- The origin of self replicating molecules making inheritance possible
Protocell
Droplets with membranes that maintain an internal chemistry different from their surrounding
What was the early atmosphere like?
Filled with nitrogen and oxides, mostly carbon dioxide
What was the oparin-haldene hypothesis?
The early atmosphere was a reducing environment where organic compounds can form simpler molecules.
What did Miller-Urey do?
Tested and legitimized the Oparin-Haldene hypothesis
What did Miller-Urey hypothesize?
The first organic compounds were formed near volcanoes and deep sea vents
Which was the first genetic material?
RNA
Ribozyme
and enzyme like protein that makes copies of pieces of RNA
What’s the difference between RNA and DNA shapes
DNA are double helix and RNA have 3D shapes
stromatolites
oldest fossils, layered rocks that formed from the activities of certain prokaryotes
what is the reason cyanobacteria had a big impact on the environment?
they release oxygen into the earth’s atmosphere
what is the purpose of a cell wall?
maintain cell shape, protects the cell, prevents it from bursting in a hypotonic environment
bacterial cell walls are made of what?
peptidoglycan
peptidogylcan
a polymer composed of modified sugars cross-linked by short polypeptides
gram-positive
simple walls with a relatively large amount of peptidoglycan, stain purple
gram-negative
less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides, stain pink/orange/red
G+ or G- which is most likely to be toxic?
gram negative
G+ or G- which is most likely to be antibiotic resistant?
gram negative
capsule
a dense and well organized sticky cell wall
slime layer
an unorganized sticky cell wall
endospores
a dehydrated copy of a chromosome that can remain viable for centuries, often created when the prokaryotes life is at risk
fimbriae
hairlike appendages used to stick to the substrate or other prokaryotes
pili
appendages that pull two cells together prior to DNA transfer
taxi
a directed movement toward or away a stimulus
flagella
little tail like things that allow mobility in many cells
three parts of bacteria flagellum
motor, hook and filament
exaptation
the process in which exxisting structures take on new functions through descent with modification
do prokaryotes have organelles?
no
how do prokaryotes perform metabolic functions?
specialized membranes
ex. a folded plasma membrane
do prokaryotes have less DNA than eukaryotes?
ya
to prokaryotes have a nucleus?
no
nucleoid
a region of cytoplasm that is not enclosed by a member
plasmid
smaller rings of independently replicating DNA molecules
phototrophs
obtain energy from lights
chemotrophs
obtain energy from chemicals
autotrophs
need CO2 or related compounds as a carbon source
heterotrophs
require an organic nutrient, like glucose, to make other organic compound
obligate aerobes
must use O2 for cellular respiration
obligate anaerobes
poisoned by O2 and live by fermentation
anaerobic respiration
substances other than O2, such as nitrate and sulfate ions, accept elections at the “downhill” end of election transport chains
facultatives anaerobes
use O2 if present but can also carry out fermentation or anaerobic respiration if needed
nitrogen fixation
the conversion of atmospheric nitrogen to ammonia
heterocysts
cells that carry out only nitrogen fixation
biofilm
a surface-coating colony of one or more species of prokaryotes that engage in metabolic cooperation
binary fission
a single prokaryotic cell divides into 2 cells
genetic recombination
when genes of new prokaryote come from different places
horizontal gene transfer
movement of genes from one organism to another
transformation
genotypic/phenotype are altered by the uptake of foreign DNA from the surrounding
transduction
viruses carry prokaryotic genes from one host to another
conjugation
DNA is transferred between two prokaryotic cells that are temporarily joined
f plasmid
plasmi form of the F factor
f factor
the ability to form pili and donate DNA between prokaryotes
r plasmids
genes from antibiotic bacteria were transferred to other bacteria
extremophiles
lovers of extreme conditions, archaea
extreme halophiles
live in high saline environments, need or tolerate salt
extreme thermophiles
thrive in very hot environments
methanogens
archaea that release methane as a by-product of obtaining energy
decomposers
prokaryotes that absorb nutrients from organic material and converts them to inorganic forms
symbiosis
an ecological relationship in which two species live in close contact with each other
host
the larger organism in symbiosis
symbiont
the smaller organism
mutualism
an interaction where both species benefit
commensalism
where one species benefits and the other is not harmed or helped
parasitism
where one species benefits and the other is harmed
pathogen
a parasite that causes diseases
exotoxins
proteins secreted by certain bacteria and other organisms that cause illness
endotoxins
on the outer membrane of G- bacteria that are only released when the bacteria die and their cell walls break down
bioremediation
the use of organisms to detoxify and restore polluted and degraded ecosystems
