for every 2 e transported from NADH to O2, 10 H+ are transported for every 2 e transported from FADH2 to O2, 6 H+ are transported

Week 7 Flashcards by Tami Ojewole

oxidative phosporylation (def.)

using reducing power from glycolysis + krebs cycle (citric acid cycle) to generate proton motive force which is used to make ATP

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aerobic respiration (def.)

use of O2 as final electron acceptor; uses ETC

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anaerobic respiration (def.)

use of an inorganic molecule other than oxygen as final electron acceptor; uses ETC (ex. NO3-, SO42-, CO2, Fe3+), uses ETC

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fermentation (def.)

not a respiration (doesn’t uses ETC); use of an organic molecule as final electron acceptor (ex. pyruvate)
-no ETC, no PMF, no oxidative phosphorylation

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ETC is located where?

-plasma membranes of chemoorganotrophs in bacteria and archaeal cells
-internal mitochondrial membranes in eukaryotic cells

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ETC generally contains _______

Complexes I, II, III, IV

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ETC is a series of _____ operating together to do what?

-e- carriers
-transfer electrons from NADH and FADH2 to a terminal e- acceptor (O2, NO3-, SO42-. CO2)

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e- flow in ETC from carriers with ______ to _____

-more negative reduction potentials (E0) to carriers with more positive E0

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entry point of ETC is at either _____, both reduce _____, electrons come from ____ and protons come from ____

Complex I or Complex II,
-ubiquinone (Q) to ubiquinol (QH2)
-NADH or FADH2
-cytoplasm

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ETC: Complex I takes 2 electrons from _______ in the cytoplasm, Also undergoes conformational changes that pump _____

-NADH, leaving H+ and NAD+
-4 H+ to the periplasm

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ETC: Complex II is the ______ complex, part of the _____; gives 2e- to _____

-succinate dehydrogenase (doesn’t add to PMP)
-citric acid cycle (makes FADH2)
-ubiquinone

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Even though both NADH and FADH2 only give 2 e- to _____,
NADH produces ______

-ubiquinone
-more energy overall because of additional 4 H+

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Complex III takes 2 e- and 2 H+ from _____, plus an additional 2 H+ as part of the Q cycle (transfers e- to ______, transfers H+ to ____). Cytochrome C shuttles e- to _____. Complex IV reduces _____, causes _____ to move from cytoplasm to periplasm

-ubiquinol (from cytoplasm)
-cytochrome C
-cytosol/periplasm
-Complex IV
-final electron acceptor
-2 more H+

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ETC summary (H+)

-Complex I (pumps 4H+)
-Complex III (pumps 4H+)
-Complex IV (pumps 2H+)

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ETC net result

for every 2 e transported from NADH to O2, 10 H+ are transported
for every 2 e transported from FADH2 to O2, 6 H+ are transported

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ATP synthase

-Fo in membrane; F1 in cytoplasm (catalytic component)
-ATP synthase can go backwards
-C protein spins gama to spin -> conformational change (ADP-> ATP)
-a/B after rotation of shaft gamma (y)

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Oxidative phosphorylation take _____ ions to make one ATP

-~3 H+ (not exact)

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Glycolysis + citric acid cycle yields a potential _____ per glucose (____ from substrate level phosphorylation and ___ from oxidative phosphorylation)

-38 ATP
-4
-34

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Factors affecting ATP yield

PMF is also used for other things (motility, active transport)
Intermediates may be used to synthesize other molecules
ETC may be shorter in some bacteria/archaea

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Fermentation can occur when: ______

-there is an abundant supply of sugars
-Can also occur when ETC is unusable (i.e. there is no oxygen)

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Fermentation: sufficient ATP is generated by _____; The final electron acceptor is an _____

-glycolysis
-organic molecule (i.e. pyruvate)

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Lactic acid fermentation

pyruvate —> lactate (NADH -> NAD+)
-glycolysis: glucose -> 2 pyruvate (make 2ATP, 2NADH)
-2 pyruvate + 2 NADH = 2 lactate + 2 NAD+

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fermentation that produces ______: alcohol/bread/beverages

CO2 AND H2

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fermentation that produces ______: alcoholic fermentation

ethanol

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fermentation that produces ______: cheese and yogurt but also food spoilage

lactic acid

alcoholic fermentation makes _____. homolactic? heterolactic?

-2 ethanol + 2 CO2 -2 lactate + 2H+ -lactate + ethanol + CO2

chemolithotroph can't undergo _____

fermentation

E.coli aerobic respiration is when _____. descr.

-O2 is present -Complex I (pumps 4H+), Complex II, Cytochrome bo3 (hybrid complex III & IV) (pumps 4H+) -NADH: 8 H+, FADH2: 4 H+

E.coli anaerobic respiration is when _____. descr.

-O2 is absent but NO3- is present -Complex I (pumps 4H+), Complex II, nitrate reductase (hybrid complex III & IV) (pumps 2 H+) -NADH: 6 H+, FADH2: 2 H+

Chemolithotrophs get reducing power from ____; almost all are ____

-oxidation of inorganic molecules -extremophiles

examples of chemolithotrophs (3) + source of e-

-iron bacteria (Fe2+) -nitrifying bacteria (NO2-) -chemotropic purple sulfur bacteria (S2-)

iron-reducing bacteria has ____

electrically conductive pili (has Fe3+ containing minerals), e- travel out through conductive pili to reduce iron oxide minerals outside the cell

Phototrophy (def.)

use of light to make chemical energy (ATP and NAD(P)H)

oxygenic photosynthesis uses _____ as an electron donor and makes ____ (ex. _______)

-water -O2 -eukaryotes and cyanobacteria

anoxygenic photosynthesis typically uses ____ as an electron donor to make ____ (ex. ________)

-sulfide -sulfate -purple and green sulfur bacteria)

nonphotosynthetic phototrophs use _____ to generate _____ (ex. ______)---> still uses ____

-bacteriorhodopsin -PMF -some bacteria like Roseobacter and some archaea, like the halophiles) -light but they don't undergo photosynthesis

anoxygenic photosynthesis does not produce ____ while oxygenic photosynthesis produces it

______ is the major light capturing molecule; Structurally similar to ____;Uses ___ instead of Fe

-Bacteriochlorophyll -heme -Mg

Accessory pigments can also transfer ____ to chlorophylls * e.g., ______ * accessory pigments absorb _____ of light than chlorophylls

-light energy -carotenoids and phycobiliproteins -different wavelengths

photosynthesis

* light is harvested by protein complexes containing bacteriochlorophyll * converts P870 into a strong electron donor * reduces ubiquinone to ubiquinol * transfers H+ and e to cytochrome, same as for chemoheterotrophs * electrons (lower energy) are transferred back to P870

Some archaea use a type of phototrophy that involves ____, a membrane protein which functions as a ______. A proton motive force is ____. An _____ is not involved

-bacteriorhodopsin (has retinal) -light-driven proton pump -generated -electron transport chain

carbon source= organic compounds: _____

hetero-

carbon source= inorganic compounds: _____

auto- (needs to contain C, usually CO2)

organic carbon sources include _____. inorganic carbon source is almost always ____

-peptides, sugars, lipids etc. -CO2

autotrophs do what?

fix CO2

cycles to fix CO2 by autotrophs

* Calvin cycle * Reductive TCA cycle * Hydroxypropionate bi-cycle * Reductive acetyl-CoA pathway * 3-hydroxypropionate/4-hydroxybutyrate pathway

Calvin cycle also called _____, used by _____

-reductive pentose phosphate pathway -most autotrophs to fix carbon

Calvin cycle summary

6 RubP + 6CO2 + 6 H20 = 12 PGA --> 12 G3P (makes 12ADP & 12NADP+) 2 G3P -> synthesis of organic molecules (glucose, sucrose etc.) 10 G3P + 6ATP = 6 RubP

calvin cycle occurs in ______

-carboxysomes in some bacteria (cyanobacteria, nitrifying bacteria and thiobacilli) -> carbonic anhydrase makes CO2 from carbonic acid & 3-phosphoglycerate (CO2 + ribulose-1,5-biPO4) -stroma of chloroplasts in eukaryotes

Three phases of Calvin cycle

* carboxylation phase * reduction phase * regeneration phase

Calvin cycle: _____ and _____ are used during the incorporation of one CO2

-Three ATPs -two NADPHs

Calvin cycle: ____is an intermediate in glycolysis→ used to make _____

-3-phosphoglycerate -glucose (gluconeogenesis)

the reductive TCA cycle aka _____; used by _____; makes ____

-opposite of Krebs/TCA cycle (requires e-, ATP) -some chemolithoautotrophs -acetyl-CoA -> G3P

Assimilation (def.)

incorporation of inorganic molecules (nitrogen, phosphate, sulfur) into organic ones

nitrogen is major component of _______. potential sources of nitrogen: _______. ______ easily incorporated into organic material because it is _____ than other forms of inorganic nitrogen

-protein, nucleic acids, coenzymes, and other cell constituents -ammonia, nitrate, or nitrogen -Ammonia nitrogen -more reduced

enzymes needed for ammonia incorporation

-glutmate dehydrogenase -glutamine synthetase (needs energy) -transaminase (moves NH3 around) -gutamate synthase forms 2 glutamates

glutamine synthetase produced by _____; does what?

-most bacteria -glutamate -> glutamine

Where does ammonia come from?

* Other organisms * Environment * N2 via nitrogenase (found only in bacteria and archaea, Requires large ATP expenditure, once reduced, NH3 can be incorporated into organic compounds)

nitrogenase is ____to O2, needs _____

-sensitive -Use thick glycocalyx to keep out O2 (Make a heterocyst --> Thick-walled cell that does not use aerobic respiration)

Phosphorus found in nucleic acids as well as _____

-proteins, phospholipids, ATP, and some coenzymes

Most common phosphorus sources are ____ and ______

- inorganic phosphate - organic phosphate esters

Inorganic phosphate (Pi) incorporated through the formation of ATP by ____

* oxidative phosphorylation * substrate-level phosphorylation

Organic phosphate esters

* present in environment in dissolved or particulate form * hydrolyzed by phosphatases, releasing Pi

Sulfur needed for: ____

* synthesis of amino acids cysteine and methionine * synthesis of several coenzymes

Sulfur obtained from

* external sources * intracellular amino acid reserves

Sulfate = ____

inorganic sulfur source

Sulfate comes from ______

oxidation of reduced sulfur (S0 or HS-)

sulfate reduced to ____ and then used to synthesize _____. Cysteine can then be used to form _____

-H2S -cysteine -sulfur containing organic compounds

Dissimiliative sulfate reduction

H2S is excreted; uses APS (SO4+ ATP)

Assimiliative sulfate reduction

H2S is incorpated into organ sulfur compounds (cysteine, methionine, and so on); uses PAPS(SO4+ 2ATP)

sulfur assimilation occurs in most _____; serine --->

bacteria -serine + AcCoA --> O-acetylserine + HS- --> cysteine + acetate

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Week 7 Flashcards

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