Exam 3: ETC Flashcards
Where does the ETC happen
in mitochondrial inner membrane
What kind of complexes are in the ETC
transmembranes, complex 2 not quite across full membrane
Describe how electrons travel through complex 1
FMN picks up H+ from NADH and transfers it to iron sulfur clusters then to ubiquinone
What is ubiquinone
an organic molecule with a long HC tail that can take an e- from complex 1 and or 2 to complex 3
What other name does complex 3 have
cytochrome BC complex
What is the Q cycle
process of moving through complex 3 to cytochrome C
What does UQ do after the e passes through complex 3
takes e- and transfers it to cytochrome C
How many e- are transferred from cytochrome C to complex 4
4e-
What is the respirazome / supramolecular complex
complex 1-3 to cytochrome C, complex is close together to help reduce RO species
How does antimycin allosterically inhibit the ETC
blocks NADH and FADH from using O2 in complex 3
How is O2 consumption affected when complex 1 is allosterically inhibited
NADH no O2 consumption
still allows some O2 consumption from FADH2
What is the process happening after ETC in the ATP synthase called
oxidative phosphorylation
What are the tallies of H+ for ETC from NADH and FADH2
NADH: complex 1-3 (4H+ each), complex 4 (2H+), total 10 H+
FADH2: complex 3: 4H+
complex 4: 2 H+, total 6H+
Name 2 uncouplers that can disrupt the ETC
dinitrophenol: sits in membrane can pick up H+
gramicidin: transmembrane protein that forms pure form of H+ (deadly)
What are the 2 subunits of ATP synthase
Fo (rotor) and F1 (enzyme activity)
What subunits does Fo have
1a (stationary, attached to c-ring), has 2 half channels
1b: attaches the Fo to F1
What does the F1 unit do, what is it made of
catalyzes rxn, made of 3 alpha and 3 beta subunits forming hexomer together
What does the stalk do and what is it made of
anchor, E (epson) and gamma subunits form stalk, sigma subunit is achor
Where does H+ enter the ATP synthase
half channel in subunit 1A from innermembrane space goes to C subunit
Explain the steps after H+ enters ATP synthase
C subunit gets H+ binds to Asp, causes shifting of C unit, Ring A unit is stationary. shift causes conformation change in epson and gamma subunits of FO, causes conformation shift of alpha beta subunits in F1, this catalyzes ADP+ Pi –>ATP
Where do the 2 half channels of subunit 1a go
1 open to matrix
1 open to innermembrane space
Where do the 3 conformation changes LTO happen
beta subunit of F1
Explain what L, T and O mean
L: loose, inactive high affinity for ADP+Pi
T: tight, active, high affinity for ADP+Pi
O: open, inactive, low affinity for ADP, Pi and ATP
What does it mean when the P/O ration is high
high: ETC and ATP synthase are making lots of ATP
low: making less ATP but pumping lots of H+
What is the P/O ratio
moles of Pi consumed (ATP synthase)/ O2 reduced to H2O (complex 4)
What risk is there to having a low P/O ratio?
can cause increase in O2 reactive species
What are the ADP and ATP translocators
allow ATP out and ADP in, an antiport, negatively regulated by ADP in
What is phosphate translocase
HPO4 and H+ symport
How many H+ does ATP synthase need to produce 1 ATP
3H+
The ultimate e- acceptor if the mitochondrial electron transport system is
O2
In complex 3 electrons are transferred from UQH2 to
cytochrome C
The final product of oxidative phosphorylation is
ATP
The reducing power generated in the cytoplasm can be transferred to the mitochondrion by which processes?
glycerol phosphate and malate asp shuttle
Which of the following is not a step of ATP synthesizing process
The O conformation binds to ADP and pi
How many protons are needed to drive the phosphorylation of ADP by the mitochondrial ATP synthase
4H+
What is not a component of ETC and not an e- carrier
coenzyme A
In the ATP synthase, the Fo factor
has 3 types of subunits and is a transmembrane proton channel
