Lecture 12: Prokaryotes Flashcards
prokaryotes vs eukaryotes: unicellularity
- prokaryotes: typically unicellular (can form colonies or filaments)
- eukaryotes: uni or multicellular
prokaryotes vs eukaryotes: internal structure
- prokaryotes: no membrane bounded organelles & cytoskeleton (thus enzymes and cell proteins are either free floating or embedded in cell membrane)
- eukaryotes: highly compartmentalized, many organelles
prokaryotes vs eukaryotes: chromosomes
- prokaryotes: single, circular DNA chromosome in a nucleoid region
- eukaryotes: double membrane bound nucleus with multiple linear chromosomes
prokaryotes vs eukaryotes: cell division
- prokaryotes: binary fission
- eukaryotes: mitosis
binary fission
- prokaryotes replicate by a type of simple cell division where they divide into two
- -> can reproduce every 20 mins or up to days
- -> can suspend their division for more than a century
prokaryotes vs eukaryotes: gene transfer
- prokaryotes: lateral transfer
- eukaryotes: recombination
lateral transfer
- the movement of chunks of DNA from one prokaryote to another
- crosses species’ borders
prokaryotes vs eukaryotes: cell wall
- prokaryotes: ubiquitous; have peptidoglycan or pseudomurein (ubiquitous= they all have cell walls)
- eukaryotes: in some organisms(plants, fungus, protists); no peptidoglycan
prokaryotes vs eukaryotes: size
- prokaryotes: typically small
- eukaryotes: typically large
flagella
-found on some cells in both groups always leading to mobility
peptidoglycan
- polysaccharide
- polymer of sugars and amino acids
- stiffened and made firm in varying amounts of this
pseudomurein
- does same thing as peptidoglycan
- found in archaea
- polysaccharide
thermotoga maritima
- bacteria that can survive in extremely high temperatures
- shows that their traits aren’t being passed down vertically through time but instead horizontally (lateral transfer)
gram + cells
- stains purple
- a lot of peptidoglycan
- their cell wall has a thick layer of peptidoglycan
gram - cells
- stains pink/red
- little/no peptidoglycan
- their cell wall has a thin layer of peptidoglycan
- i.e. Archaea
how was bacteria classified before genetic analysis?
- shape (sphere, rod, spiral)
- metabolism
- gram + or -
- motile or not
- photosynthetic or not
- unicellular, colony forming, or filamentous
types of bacterial shapes
- coccus
- bacillus
- spirillum
metabolism
-how organisms gain nutrients
obligate aerobes
-need oxygen
obligate anaerobes
-don’t oxygen
facultative anaerobes
-can move btwn anaerobic forms of metabolism (fermentation) and aerobic forms (cellular respiration)
aerotolerant anaerobes
- aka “air tolerant”
- cannot use O2 for their metabolism(don’t need it) but they’re not harmed by O2
autotrophs
-self feeders
heterotrophs
-other feeders
which group have all four metabolic styles?
-bacteria
photoautotrophs
- has chlorophyll
- energy source: light
- carbon source: CO2
- chlorophyll converts light to energy & this with water (electron donor) are used to break down the CO2 to gain carbon and release O2 in the process
- only in bacteria and archaea
chlorophyll
-pigment to gain energy
chemoautotrophs
- energy source: chemical bonds
- carbon source: CO2
- breaking bonds of inorganic chemicals and capture the energy stored within those bonds to break down CO2 as their carbon source to make sugars
- found on seafloor near hot hydrothermal vents; no sunlight
photoheterotrophs
- energy source: light
- carbon source: eating other organisms
- use bacteriochlorophyll to convert energy from the sun but can’t break down CO2 so they gain carbon from organic compounds that have been made by other organisms
heterotrophs
-energy & carbon source: other organisms
thermophilic
-heat loving
cryophilic
-cold-loving
halophilic
-salt-loving
acidophilic
-acid-loving
metagenomics
- study of genetic material recovered directly from environmental samples
- the techniques are helping us to learn more ab prokaryotic archaeans
archaea characteristics
- have no peptidoglycan
- gram -
- most love extreme environments but not all
what does prokaryote mean?
-pre-nucelus
