2. 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
3. Photosynthetic organisms
Capture light energy and use it to drive the
synthesis of organic compounds from CO2
Ex: Cyanobacteria, plants and algae
4. 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
5. Use light energy but must get carbon in an
organic form
Used by some marine prokaryotes
Ex: Rhodobacter and Chloroflexus
6. Their energy source is organic compounds
and they require organic carbon
Many prokaryotes, fungi, animals and some
plants use this
Ex: Clostridium
7. 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
8. Other obligate anaerobes extract chemical
energy by anaerobic respiration—substances
other than O2 accept electrons at the
“downhill” end of electron transport chain
9. Some prokaryotes convert atmospheric
nitrogen (N2) to ammonia (NH3)
This „fixed‟ nitrogen is incorporated into
amino acids and other organic molecules
10. Cooperation: working together
Some proks can‟t use resources by
themselves
◦ No specialized organelles!
Cooperation between specialized cells
Exchange of metabolic products
11. 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!!!!!
12. Biofilm = surface-coat colonies w/ metabolic
cooperation
Signaling molecules
Channels between cells allow flow of
nutrients
Other species can cooperate as well
