Phototrophy, Chemolithotrophy, & Biosynthesis (E2) Flashcards
Photoautotrophy combines the { } rxn (energy step) and { } rxn (carbon fixation).
1) Light
2) Dark
Another name for the light reaction.
What is photophosphorylation?
Another name for the dark reaction.
What is the Calvin cycle?
This type of phototrophy releases oxygen.
What is oxygenic?
This type of phototrophy is only seen in prokaryotes and doesn’t result in oxygen release.
What is anoxygenic/anaerobic?
This type of phototrophy converts sun energy to ATP in non-photosynthetic prokaryotes but can’t use CO2 to make organic molecules.
What is Rhodopsin-based?
What are the primary pigments for oxygenic and anoxygenic phototrophy, respectively.
Oxygenic - chlorophyll
Anoxygenic - bacteriochlorophyll
Oxygenic phototrophy uses { } photosystem(s) while anoxygenic uses { }.
1) 2
2) 1
What are the electron donors for oxygenic and anoxygenic phototrophy, respectively?
Oxygenic - H2O
Anoxygenic - H2, H2S, reduced iron
This type of phosphorylation produces only ATP.
What is cyclic?
This type of phosphorylation produces ATP, NADPH, and O2.
What is non-cyclic?
What molecule is split as a source of electrons to make NADPH in oxygenic phototrophy?
Water
Why is reverse electron flow considered energy-expensive?
It requires ATP
Why is reverse electron flow important to anoxygenic phototrophy?
Generating reducing power
What are the 3 requirements for biosynthesis?
1) Organic elements (HONC)
2) Reducing agents (NADPH)
3) Energy
What can biosynthetic reaction intermediates be used for?
Precursor metabolites for other pathways
What is the purpose of the Calvin cycle?
To consume energy (ATP, NADPH) to fix CO2
What are the 3 steps of the Calvin cycle?
1) Carboxylation
2) Reduction
3) Regeneration of RuBP
This organelle, present in some bacteria, increases the efficiency of light absorption.
What are thylakoids?
What is the purpose of the carboxysome?
To store enzymes required for reducing CO2 into sugars
Given that the Calvin cycle is a biosynthetic process, it can be said to be…
Anabolic
Since archaea have no true photosystems, what pigment complex do they use to capture radiant energy via light-driven PMF?
Bacteriorhodopsin
Given that the prefix “lith” in lithotrophy means stone, lithotrophy requires { } compounds to serve as electron donors and an energy source.
Inorganic
Name 3 chemolithotrophic electron donor processes.
1) Sulfur & metal oxidation
2) Nitrogen oxidation
3) Hydrogenotrophy
