1. Alex, Maya, Michelle

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