Flashcards in Metabolic Diversity Deck (45)
What are the types of oxygen requirements?
- aerobes: require O2 for growth
- anaerobes: O2 not required for growth
- facultative aerobe: O2 is not required but it does enhance growth
What are the options for energy sources?
chemicals or light
What are the options for e- sources?
organic or inorganic compounds
What are the options for carbon sources?
organic or inorganic
Where do phototrophs get their energy from?
Where do chemoorganotrophs get their energy from?
Where do chemolithotrophs get their energy from?
Where do heterotrophs get their carbon from?
Where do autotrophs get their carbon from?
What is the formula for sulphur respiration and who uses it?
HS- to S0
facultative aerobes and obligate anaerobes
What is the formula for sulphate respiration/reduction and who uses it?
HS- to (SO3)2-
What is the formula for nitrate respiration and who uses it?
NO2- to NO3-
What is the formula for denitrification and who uses it?
N2 to NO3-
Denitrifying bacteria use ___ sources of energy/C/e-
Denitrifying bacteria: N compounds are common ___ (anaerobic), N2/NO/N2O are gasses that are commonly ___ (this is ___ for agriculture and ___ for sewage treatment)
final e- acceptor/lost/bad/good
What are the two steps of denitrifying?
1. nitrate reduction (NO3-->NO2) ex. E. coli using nitrate reductase
2. denitrifying: NO3-->NO2 (nitrate reductase) --> NO --> N2O --> N2
What is the energy/C/e- source for sulphate and sulphur reduction?
Bacteria can use ___ or ___ as e- acceptors and can use either organic or inorganic compounds for ___, it uses ___ as the terminal e- acceptor and ___ as the e- donor
(SO4)2/(SO3)2/e- donor/S0/acetate or ethanol or organic compounds
What is responsible for the rotten egg smell and is the end product of sulphur reduction?
True or false: in phototrophs the light sensitive pigments have diverse absorption spectrums
Define the reaction centre
the small fraction of pigments in the photo complexes formed by bacteriophyll/chlorophyll and PRO that participate directly in photosynthesis
pigments surrounding the reaction centre act as ___ to ___ and ___ to the reaction centre
antennae/harvest light/funnel energy
hydrophobic, light-sensitive pigments embedded in the photosynthetic membrane, their primary role is to protect from light damage
What are phycobilins?
they form complexes with PRO that are the main light harvesting system in cyanobacteria and harvest light from different wavelengths than chlorophyll
Where does photosynthesis happen in eukaryotes?
A pmf is generated across the thylakoid membrane (in the chloroplast)
The stroma is ___ and the thylakoid space is ___
alkaline and negative/acid and positive
Where does photosynthesis happen in bacteria?
the pigments are integrated int the internal membranes (heliobacteria=cytoplasmic membrane, purple bacteria=intracytoplasmic membrane, cyanobacteria/prochlorophytes=thylakoid membrane)
What are chlorosomes?
Present in green sulphur and non-sulphur bacteria, they are large antennae networks of bacteriophylls (c, d, and e) that transfer energy to the reaction centre ( bacteriophyll a)
What is the best system to capture light in low light environments?
Describe anoxygenic photosynthesis in purple bacteria
- H+ accumulates in the periplasm/vesicles/intracytoplasmic membrane
- cytoplasm is -
- light enters LH II and LH I and transports the electrons through the system
- NADH is made by reverse e- flow (e- go from C2 to C1 to reduce NAD)
- very low yield
Describe an oxygenic photosynthesis in green bacteria
- cyclic phosphorylation: no need for e- donor because e the e- cycle and create a pmf
- reducing power=needs an e- donor for NAD->NADH (ferredoxin), oxidation of reduced S compounds is an e- source
- two parallel systems: pmf->ATP and NAD->NADH
Describe oxygenic phosphorylation
H2O->O2+2H+2e-, e- ->e- chain->NADPH (creates pmf->ATP)
- noncyclic phosphorylation: pair of e- is used to produce pmf and NADPH
- when reducing power is enough for cell needs e- return to cyt bf because there is no need for additional e- source (cyclic)
In some cyanobacteria, H2S ___ PSII so ___ H2S becomes the main source of ___ which makes the e- chain become ___.
e- from ___ -> e- chain that creates ___
e- from ___ -> e- chain->NADPH
What are chemoautotrophs?
- primary producers
- inorganic energy/e-/C source
What classification do nitrifying bacteria and sulphur bacteria fall under?
Nitrifying bacteria use ___ as e- donor
inorganic N compounds
What do the two groups of nitrifying bacteria do and what is the total result?
1. HN3->NO3 (ox)
2. NO2->NO3 (ox)
Is nitrification aerobic or anaerobic?
For nitrosomonas: ___ is the final e- acceptor, 2e- are supplied by ___ which allows AMO to ___ NH3. NADH is produced by ___ (pmf energy source).
O2/Q/oxidize/reverse e- flow
For nitrobacter: ___ is the final e- acceptor, NXR=___, NADH produced by ___ with pmf energy source
O2/nitrite reductase/reverse e- flow
What do sulphur bacteria do?
- oxidize S compounds
- O2 is final e- acceptor
- produces SO4 and protons
What do methanogens do? What is the formula?
produce CH4 anaerobic
4H + CO2 -> CH4 + 2H2O + energy/ CH3COOH->CH4+CO2+energy
What do methanotrophs do? What is the formula?
use CH4 as an energy source aerobically
Where is CO2/Calvin cycle?
photoautotrophs (algae, cyanobacteria, purple sulphur bacteria, green sulphur bacteria), chemoautotrophs (nitrifying bacteria, sulphur bacteria, some methanogens), eukaryotes (in stroma), prokaryotes (in chloroplasts)