Chapter 11: Catabolism: Energy Release and Conservation PART 5 (slides 27-35)-Bacterial ETC and Anaerobic Respiration

Comparing ETCs, where is it located in prokaryotes? eukrayotes?

P=cell membrane

E=IMM

Comparing ETCs, both prokaryotes and eukaryotes have the same electron carriers, T or F?

false; they have different e- carriers

Comparing ETCs, what is the difference between prokaryotes and eukaryotes when it comes to formation?

P=branched

E=linear

Comparing ETCs, whos is shorter, prokaryotes or eukaryotes?

prokaryotes

Comparing ETCs, who has the lower P/O ratio, prokaryotes or eukaryotes?

prokaryotes

Is it better to have a low P/O ratio or a higer P/O ratio?

higher; the less protons pumped=less energy made

Who makes more energy, prokaryotes or eukaryotes?

eukaryotes

In bacteria. bring in more protons to make ATP is more efficient than bringing in less protons, T or F?

False, the less protons needed to be brought in to make ATP is more efficient

What complex is the most opitimal sites for bacteria?

Complex III (or HCOs)

E. coli is an example of a:

gram neg facultative anaerobic bacterium

What does Facultative anaerobic mean?

can grow in the presence or absence of oxygen (prefers oxygen)

Since bacteria has a branched ETC, the pathway is dependent on:

oxygen levels

in E. coli, what are the two possible branches it can have?

bd branch and bo branch

bd branch is seen in what phase of growth in E. coli? Why?

stationary phase; low aeration is found here (less nutrients which means less oxygen)

does bd branch have a low or high affinity for oxygen? B/c of this, does it move more or fewer protons?

higher affinity; fewer protons pumped out

bo branch is seen in what phase of growth in E. coli? Why?

log phase; high aeration is found here (more nutrients which means more oxygen)

does bo branch have a low or high affinity for oxygen? B/c of this, does it move more or fewer protons?

low affinity; more protons are pumped out

How many protons are pumped out in a bo branch? What can it make?

4; ATP

Can E. coli ferment? What does this mean?

yes; it would NOT use ETC

What is Paracoccus denitrificans?

a Gram neg facultative anaerobic soil bacterium

Can P. denitrificans ferment? What does this mean?

no; will use ETC

Can P. denitrificans use aerobic respiration?

it can

If P. denitrificans uses aerobic respiration, it will have similar ___ to mitochondrial ETC?

electron carriers

In bacteria, protons that are pumped out go to the:

periplasmic space

P. denitrificans uses what carbon source?

can be hetero or autotrophic

If P. denitrificans is hetero, where does the ETC get its NADH to donate e- from? Where does it donate the e-?

glucose; to NADH dehydrogenase (Complex I)

If P. denitrificans is auto, where does the ETC get its NADH from to donate e-? Give an example

a 1-carbon molecule such as methanol; e- is donated to cytochrome c via methanol dehydrogenase (MD)

MD=

methanol dehydrogenase

(review) a strict aerobe has what?

SOD and catalase

SOD and catalase has everything to do with whether or not an organism will:

do respiration or fermentation

What drives ATP synthesis?

PMF

ATP synthase is what complex?

Complex V

What is the best studied ATP synthase? Where is it found?

F1F0 ATP synthase; found in mitrochondria, cholorplasts, and bacteria

F1F0 ATP synthase can also catalyse:

ATP hydrolysis

F0 is the:

proton conducting channel

proton conducting channel is:

F0

F1 is a complex that catalyzes:

ATP synthesis

Where is F0 found?

in the membrane

Where is F1 found?

on top of the ceiling of the membrane (cytoplasm)

Theoretical maximum total=

total yield of ATP during aerobic respiration

What is the theoretical maximum total yield of ATP in aerobic respiration?

32 ATP (in a perfect world)

What is the theoretical maximum total yield of ATP in eukaryotes

30 ATP

Do prokaryotes have more or less theoretical maximum yield of ATP than eukaryotes? Why?

less; because of shorter ETC and lower P/O ratio

P/O ratio=

phosphate/oxygen ratio

The higher the P/O, the better or worse?

better

During aerobic respiration, 1 round of glycolysis goes through both OP and SLP. Where does this happen and how many ATP does it yield?

OP= when G3P generates NADH (2 of them since we have two G3P due to the cleaving of F6P); yields 5ATP

SLP= happens when G3P goes to 3-phosphoglycerate and when 3-phosphoglycerate foes to PEP (2 per cycle since we have two G3P; while 4 are made, we used 2 ATP in the 6 carbon stage, so ATP yield is 2)

During aerobic respiration, how many turns does the TCA cycle do after glycolysis?

two (for the two pyruvates)

Between pyruvate and Acetyl-CoA, does OP occur or SLP? What is generated and where does it go? How many ATP are yield?

OP occurs; 2 NADH are generated; goes to ETC; 5 ATP are produced

Per every 2 turns of the TCA cycle, how many NADHs are generated? Where do they go? Does this go through OP or SLP? How many ATP are yielded?

6 NADH; ETC; OP; 15 ATP

Per every 2 turns of the TCA cycle, how many FADH2 are generated? Where do they go? Does this go through OP or SLP? How many ATP are yielded?

2 FADH2; ETC; OP; 3 ATP yielded

Is there anywhere that SLP is seen in the TCA cycle? If so, where? What does it produce?

Yes; when succinyl CoA turns to succinate; produces 2 ATP yielded

In anaerobic respiration, is the elctron acceptor exo or endogenous?

endogenous

In anaerobic respiration, O2 is NOT the final electron acceptor, T or F?

true

Why foes anaerobic respiration yield less energy?

Because of the E0 of acceptor

Anaerobic respiration only happens in bacteria, T or F?

false; it is done by all three domains

What are the most common non-oxygen electron acceptors?

nitrate, sulfate, and carbon dioxide

Electron donors are ____ and in turn become ____

oxidized; reduced

What kind of bacteria commonly uses nitrate as an electron acceptor?

Enteric bacteria, pseudomonas, bacillus, and paracoccus species

What organism commonly uses CO2 as its electron acceptor?

Methanogens

In high oxygen environments, what is the general bacterial ETC for E.coli? What type of branch is this? Aerobic or anaerobic?

e-donor--->dehydrogenase--->quinone--->cytochrome c bd oxidase--->O2

branch=bd; aerobic

In low oxygen environments, what is the general bacterial ETC for E.coli? What type of branch is this? Aerobic or anaerobic?

e- donor--->dehydrogenase--->quinone--->cytochrome bo oxidase--->O2

branch=bo; aerobic

In anaerobic respiration, what is the general bacterial ETC for E. coli? What determines the final electron acceptor?

e- donor--->dehydrogenase--->quinone--->(PATH 1= fumarate reductase--->fumarate--->succinate) OR (PATH 2= nitrate reductase--->NO3--->NO2--->NH4+)

depends on what is available to these bacteria in the environment

In P. denitrificans, what does it do in anoxic conditions

dissimilatory nitrate reduction/denitrification

What does P. denitrificans do the soil? Is this good or bad for plants?

it reduces the nitrogen in the soil; bad b/c plants need nitrogen to grow

What is the terminal electron acceptor for P/ denitrificans in anoxic condtions?

Nitrate

In dissimilatory nitrate reduction/denitrification, what is inhibited by O2?

enzymes

What also uses dissimilatory nitrate reduction/denitrification?

pseudomonas and bacillus (both are facultative anaerobes)