Quiz 3 microbio photosynthesis and ch11 1-10

Four general groups chemolithotrophs

Hydrogen bacteria oxidize hydrogen gas sulfur bacteria oxidize hydrogen sulfide iron bacteria oxidize reduced form of iron nitrifying bacteria (2 groups) oxidize 1) ammonia to nitrite or 2) nitrite to nitrate

oxygenic photosynthesis cyanobacteria

location: in membranes of thylakoids primary light harvesting pigment is chlorophyll a source of electrons for reducing power comes from h2o co2 fixation: calvin cycle accessory pigments are carotenoids and phycobilins

Light reactions

(=light-dependent reactions) - capture radiant energy and use it to generate atp and reducing power

Light independent reactions

(dark reactions) -use ATP and reducing power to synthesize organic compounds -involves carbon fixation

plants, algae

in thylakoids in chloroplast

What are three essential stages of carbon fixattion

incorporation of co2 into organic compounds reduction of resulting molecule regeneration of starting compound

Accessory pigments absorb at additional wavelengths

- carotenoids (many photosynthetic prokaryotes and eukaryotes) -phycobilins (cyanobacteria, red algae)

Light-dependent reactions: cyanobacteria and eukaryotes (plants and algae)

- two distinct photosystems (I and ii) cyclic photophosphorylation non-cyclic photophosphorylation

non-cyclic photophosphorylation

-produces both ATP and reducing power -electrons from photosystem II drive photophosphorylation -electrons are then donated to photosystem I -photosystem II replenishes electrons by splitting watter -generates oxygen (process is oxygenic) -electrons from photosystem I reduce NADP+ to NADPH

How many turns of the cycle are there for carbon fixation

6 net gain of one fructose-6-phosphate - consumes 18 ATP, 12 NADPH per fructose molecule

photosyntesis equation

6 CO2 + 12 H2X ---> C6H12O6 +12 X +6H2O X= O or S

Chemolithotrophs extract electrons from

inorganic energy sources

T or F prokaryotes are metabolically diverse

T numerous approaches to harvesting energy to produce ATP

T or F Waste products of one organism may serves as an energy source for anthother

T one mans garbage is another mans treasure

Chemolithotrophs incorporate CO2 into ...

an organic form

what did early chemotrophs likely use

anaerobic respiration others may have used fermentation

Pigments can function as

antennae pigments: funnel light energy to the reaction-center pigments reaction center pigments: excited by radiant energy (=energy of light); emit electrons that are passed to the electron transport chain

Light dependent reactions

are anoxygenic photosynthetic bacteria - only one photosystem - cannot use water as electron donor, so anoxygenic - use electron donors such as hydrogen gas (h2), hydrogen sulfide (H2S) organic compounds

what are Methanogens

are group of methane producing archaea

What are the two distinct stages in photosynthesis

light reactions and light independent reactions

what does photosynthesis do?

captures and converts radiant energy into chemical energy

Carbon fixation

chemolithoautotrophs and photoautotrophs use co2 to synthesize organic compounds

Anaerobic Chemolithotrophs

chemolithotrophs oxidize reduced inorganic chemicals to obtain energy -ex. H2 (gas) anaerobes use alternative electron acceptor - ex co2, sulfur relatively few discovered - most in domain archaea - methanogens are on group some bacteria that inhabit aquatic enviornments

photosynthetic pigments

chlorophylls (in plants, algae, cyanobacteria) bacteriochlorophylls (in anoxygenic bacteria) - absorb different wavelengths than chlorophylls

How long was the atmosphere anoxic

for first 1.5 billion years that prokaryotes inhabited earth

what is produced by anaerobic respiration from inorganic molecules (sulfate, nitrate)

hydrogen sulfide and ammonia they serve as terminal electron acceptors

Photosynthesis Oxygen

in cyanobacteria and photosynthetic eukaryotic cells

purple bacteria

in cytoplasmic membrane

Carbon fixation

in photosynthetic organisms : light-independent reactions consumes lots of ATP, reducing power - reverse process of oxidizing compounds to co2 liberates a lot of energy calvin cycle most commonly used to fix carbon but others are possible

Photosynthesis Sulfur

in purple and green bacteria

green bacteria

in specialized structures called chlorosomes attached to cytoplasmic membrane

Oxygenic photosynthesis Plants, Algae

location: in membranes of thylakoids which are within the stroma of chloroplasts type of photosystem: I AND II primary light harvesting pigment is chlorophyll a mechanism for generating reducing power:non-cyclic photophosphorylation using both photosystems source of electrons for reducing power comes from h2o co2 fixation: calvin cycle accessory pigments are carotenoids

Anoxygenic photosynthetic green bacteria

location: primarily within the cytoplasmic membrane; chlorosomes attached to the inner surface of the membrane contain the accessory pigments type of photosystem is similar to photosystem I Primary light-harvesting pigment is bacteriochlorophylls mechanism for generating reducing power: non-cyclic use of the photosystem source of electrons for reducing power: varies among the organisms in the group; may include H2S, H2, or organic compounds co2 fixation: reversed TCA Cycle accessory pigments are carotenoids

anoxygenic photosynthesis purple bacteria

location: within the cytoplasmic membrane; extensive invaginations in that membrane increase the surface area type of photosystem is similar to photosystem II Primary light-harvesting pigment is bacteriochlorophylls mechanism for generating reducing power reversed electron transport source of electrons for reducing power: varies among the organisms in the group; may include H2S, H2, or organic compounds co2 fixation: calvin cycle accessory pigments are carotenoids

Aprox how many species of prokaryotes

over 1 million species

Chemolithotrophs

pass electrons to an electron transport chain that generates a proton motive force energy of gradient is used to make atp

cyclic photophosphorylation

photosystem 1 alone produces ATP (using energy from the proton motive force) reaction-center chlorophyll is the electron donor and the terminal electron acceptor

Light Dependent Reactions green bacteria

photosystem similar to photosystem - electrons can generate proton motive force or reduce NAD+

light-dependent reactions purple bacteria

photosystem similar to photosystem II energy of electrons insufficient to reduce NAD+ Instead expend atp to use reversed electron transport NAD+

cyanobacteria

photosystems in membranes of thylakoids (inside cell)

Pigments are located in

protein complexes; the photosystems located within the photosynthetic membranes

Prokaryotes have a unique ability that is used to

reduce inorganic compounds as sources of energy

Hydrogen sulfide and ammonia

used as energy sources for sulfur bacteria and nitrifying bacteria CO2 is the source (=chemlithoautotrophs)