Powerpoint 20 Flashcards
– Use sunlight for energy and atmospheric carbon (CO2) as carbon source
Photoautotrphs
Use inorganic source for energy and use CO2 as carbon source
Chemolithoautotrophs
Use energy from sunlight, carbon from organic compounds
Photohereotrophs
– Use organic compounds for energy and carbon source
– Most common among humans and other animals
Chemoorganoheterotrophs
these are able to reduce inorganic chemicals as source of energy, they fall in to four groups
1) Hydrogen bacteria
2) sulfur bacteria
3) iron bacteria
4) Nitrifying bacteria
Chemolithotrophs
Oxidize hydrogen gas
hydrogen bacteria
Alcaligenes eutrophus
oxidize hydrogen sulfide
sulfur bacteria
oxidize reduced iron
iron bacteria
two groups of these
- one oxidizes ammonia to nitrate
- one oxidizes nitrite to nitrate
Nitrifying bacteria
generate ATP through oxidative phosphorylation
-amount of energy gained depends on energy source and terminal electron acceptor
Chemolithotrophs
these organisms thrive in specific environments
-particularly where reduced inorganic compounds are found
Chemolithotrophs
These * do not require external organic carbon source
-produce organic carbon from inorganic source through carbon fixation
Chemolithotrophs
These organisms harvest energy from sunlight
-use energy to power synthesis of organic compounds from CO2
Photosynthetic organisms
-photosynthesis
has two distinct stages
1) light dependent reactions
2) light independent reactions
photosynthesis
a. k.a. light reactions
- converts light energy to chemical energy
Light dependent reactions
a. k.a. dark reactions
- uses energy from light reactions to produce organic compounds
Light independent reactions
Photosynthetic organisms are highly visible due to light capturing pigments because of
Capturing radiant energy
these capturing pigments include
Chlorophyll and Bacteriocholorophylls
found in plants, alga and cyanobacteria
Chlorophyll
Found in purple and green photosynthetic bacteria
Bacteriocholorphylls
- Carotenoids found in eukaryotes and prokaryotes
- phycobillins found only in cyanobacteria
Accessory pigments
function as electron donors
reaction center pigments
funnels light energy to reaction center pigments
antennae pigments
In photosynthesis, converting radient energy to chemical energy, light reactions accomplish two tasks
1) synthesize ATP through photo-phosphorylation
2) generate reducing power *to fix carbon dioxide
- reducing power may be NADH or NADPH
- Choloroplasts
- PSI and PSII, Non-cyclic generates reducing power, electron source H2O, Calvin cycle, carotenoids
Plants and Algae
- Thykaoid membranes
- as above plus a specialized phycobillin
Cyanobacteria
cyanobacteria and plants and algae are
OXYGENIC reactions
- cytoplasmic membranes with invaginations
- PSII, BActeriochorophylls, reverse electron transport(GENERATE NADH!), Electron source H2S, H2 or other inorganic
Purple bacteria
- Cytoplasmic membrane
- PSI, non-cyclic, electron source H2S, H2 or other inorganic
Green bacteria
green bacteria and purple bacteria are
ANOXYGENIC reactions
- found in Archeae
- bacteriorhodopsin molecule is purple and is most efficient at absorbing green light ( absorption macimum at 568nm)
Bacteriorhodopsin
Carbon dioxide converted to organic carbon through what?
carbon fixation
- occurs in dark reactions in photosynthesis
- *consumes great deal of ATP
- Calvin cycle most common pathway
Carbon fixation
aka calvin-benson cycle
Calvin cycle
Has 3 essential stages
1) Incorporation of CO2 into organic compound
2) reduction of resulting molecules
3) * regeneration of starting compound ( PPP steps)
Calvin cycle
one molecule of fructose produces from 6 turns of cycle
-6 turns consumes 18 ATP and 12 NADPH
Calvin cycle
