Nutritional diversity is greater in prokaryotes than eukaryotes Phototrophs-organisms that obtain energy from light Chemotrophs-those that obtain energy from chemicals Autotrophs-organisms that only require CO2 as a carbon source Heterotrophs-organisms that require at least 1 other organic nutrient to make other organic compounds
Photosynthetic organisms Capture light energy and use it to drive the synthesis of organic compounds from CO2 Ex: Cyanobacteria, plants and algae
Also only require CO2 as a carbon source and oxidize inorganic substances like ammonia, hydrogen sulfide Mode of nutrition unique to certain prokaryotes Ex: Sulfolobus
Use light energy but must get carbon in an organic form Used by some marine prokaryotes Ex: Rhodobacter and Chloroflexus
Their energy source is organic compounds and they require organic carbon Many prokaryotes, fungi, animals and some plants use this Ex: Clostridium
Obligate aerobes: use O2 for cellular respiration—cannot grow without it Facultative anaerobes: use O2 if present but can grow by fermentation in an anaerobic environment Obligate anaerobes: poisoned by O2; some live exclusively by fermentation
Other obligate anaerobes extract chemical energy by anaerobic respiration—substances other than O2 accept electrons at the “downhill” end of electron transport chain
Some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3) This „fixed‟ nitrogen is incorporated into amino acids and other organic molecules
Cooperation: working together Some proks can‟t use resources by themselves ◦ No specialized organelles! Cooperation between specialized cells Exchange of metabolic products
Ex. Cyanobacteria Anabaena can photosynthesis + nitrogen fix Photosynth. produce O2, inactives nitrogen fixing enzymes Live in colonies Most carry out photosynth., others nitrogen fix Heterocytes = “other cells” (nitrogen-fix) Heterocytes surrounded by cell wall, inhibits O2 entry Transport between cells FUNCTION OF CONCENTRATION GRADIENTS AND CELL SPECIALIZATION!!!!!
Biofilm = surface-coat colonies w/ metabolic cooperation Signaling molecules Channels between cells allow flow of nutrients Other species can cooperate as well
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.