ETC / OxPhos (complete) Flashcards
What is the energy currency in the cell
ATP
What is the difference between anabolic and catabolic processes
Anabolic processes build up things and use energy
Catabolic processes break things down, and produce energy
What are the three different phases of cellular respiration
- Nutrient catabolism
- Citrate/Krebs cycle
- Oxidative phosphorylation
what is nutrient catabolism
the breakdown of molecules, and preparation of them to enter the krebs cycle
What is the main precursor to the citrate cycle
Acetyl-CoA
What is the main function of the citrate cycle
to produce ATP and reducing agents (NADH, FADH)
is the citrate cycle better at producing ATP or reducing agents
reducing agents
Which metabolic fuels are converted into Acetyl-CoA before entering the Krebs cycle
- glucose
- ketones
- fatty acids
- Some amino acids
Which metabolic fuels don’t need to be converted into Acetyl-CoA before entering the Krebs cycle
some amino acids
how many NADH, FADH, and ATP does one cycle of the Krebs cycle produce
3 NADH
1 FADH
1 ATP
How many ATP does one cycle of the krebs cycle lead to (after the NADH and FADH go through ETC/OxPhos
10
For a glucose molecule in aerobic conditions how many cycles of the krebs cycle do we get
2
for a ketone how many cycles of the krebs cycle do we get
2
For Beta Oxidation how many NADH’s FADH’s and Acetyl-CoA’s do we get
you take the number of carbons in the fatty acid, divide that number by two. that is the number of Acetyl-CoA’s you get.
Take the number of carbons in the fatty acid, divide that number by two, then subtract one from that number. that is the number of FADH, and NADH you get
How many ATPs do you get from the beta oxidation of palmitate
106.
Don’t forget to subtract 2 for charging the fatty acid
What are the intermediates of the Krebs cycle
Acetyl-CoA Citrate Isocitrate alpha-ketoglutarate Succinyl-CoA Succinate Fumarate Malate Oxaloacetate
Which of the steps of the krebs cycle are irreversable
Citrate synthase
Isocitrate dehydrogenase
alpha-ketoglutarate dehydrogenase
What is the citrate synthase step
the step of taking oxaloacetate and Acetyl-CoA and making Citrate
What are the regulators of citrate synthase
None, but it is indirectly impacted by high levels of NADH
(this lowers Oxaloacetate and Acetyl-CoA
What is the isocitrate dehydrogenase step
the step that creates NADH and CO2
goes from isocitrate to alpha-ketoglutarate
What are the regulators of isocitrate dehydrogenase
ATP, and NADH (high energy in the cell will inhibit the krebs cycle)
What is the alpha-ketoglutarate dehydrogenase step
The second step that creates NADH and CO2
goes from alpha-ketoglutarate to succinyl-CoA
What are the inhibitors of alpha-ketoglutarate dehydrogenase
ATP/GTP and NADH
what is the purpose of the Electron transport system, and oxidative phosphorylation
to Use FADH and NADH to create ATP
where is oxidative phosphorylation occuring
the inner mitochondrial membrane
What is the electron transport system and what does it do
it is the transport of electrons from NADH, or FADH until they are used to reduce O2 to H2O. (it forms the H+ gradient)
What is oxidative phosphorylation
the generation of ATP by ATP synthase using the H+ gradient established by the electron transport system
How many complexes are there in the ETS
4
What are the two transporters in the ETS
ubiquinone (CoQ) Cytochrome C (Cyt C)
What happens at complex one of the ETS
- NADH donates 2 electrons
2. pumps 4 hydrogens
What happens after complex one of the ETS
the 2 electrons go to ubiquinone
What happens at complex two of the ETS
- FADH donates 2 electrons
2. , No hydrogen is pumped
What happens after complex two of the ETS
the 2 electrons go to ubiquinone
What happens with the electrons in ubiquinone
they are donated to complex 3
What happens at complex three
2 protons are pumped
electrons are moved to Cyt C
What happens to the electrons that Cyt C has
they are donated to complex 4
what happens at complex 4 of the ETS
- 4 protons are pumped
2. protons received from Cyt c are added to O2 to create H2O
how many H2O are produced from each NADH and FADH that goes through the ETS
2 per each NADH
2 per each FADH
What are the two sections of ATP synthase
F (knot) - imbedded in the inner mitochondrial membrane
F 1 -extends into the mitochondrial membrane
what are the parts of the F (knot)portion of ATP synthase
c subunits
a subunit
gamma subunit
what is the function of the c subunits of the F (knot) portion of ATP synthase
form a protein rotor that rotates as proteins bind from the intermembrane space
What is the function of the a subunit of the F (knot) portion of the ATP synthase
this is next to the c subunits, it creates the channel through which H+ moves into the mitochondrial matrix
What is the function of the y subunit of the F (knot) portion of the ATP synthase
the connecting portion between F (knot) and F1 sections. maintains the turning of the c subunits
what are the parts of the F 1 portion of atp synthase
alpha and beta subunits
What is the function of the alpha and beta subunits of the F 1 portion of ATP synthase
bind ADP and Pi and catalyzes the synthesis of ATP
for each ATP formed by ATP synthase, how many H+ are pumped through ATP synthase
4
why do we need ATP and ADP to move in and out of the mitochondria
ATP needs to leave to supply energy to the cell
ADP needs to enter so that ATP can be made by ATP synthase
since the mitochondrial membranes are impermeable to ions, how do we move ATP and ADP in and out of the mitochondria
transmembrane proteins
what are the transmembrane proteins that transport ATP out of the mitochondria and ADP into the mitochondria
ANT (Adenine nucleotide translocase)
VDAC (Voltage-Dependent anion channel)
What is the difference between ANT and VDAC
ANT is found in the inner mitochondrial membrane, it allows ATP out from the matrix into the intermembrane space, and ADP from the intermembrane space into the matrix
VDAC is found on the outer mitochondrial membrane, it allows ATP to go from the intermembrane space out to the cytosol, and ADP from the cytosol into the intermembrane space
Can NAD/NADH diffuse across the mitochondrial membranes
nope
What are the two types of NADH shuttles
Malate-Aspartate Shuttle
Glycerol-3-phosphate shuttle
How does the Malate-Aspartate Shuttle work
- NADH in the cytosol is converted into NAD, and reduces Oxaloacetate into Malate
- Malate is shuttled into the Mitochondial matrix through the Malate transporter
- Malate is reoxidized to oxaloacetate and reduces NAD+ to NADH in the mitochondrial matrix
- Oxaloacetate is then converted into aspartate in the matrix
- aspartate leaves the mitochondrial matrix through the aspartate transporter and enters the cytosol
- Aspartate then is reconverted to oxaloacetate in the cytosol
Why doesn’t oxaloacetate just move straight through the mitochondrial membranes in the malate-aspartate shuttle and cut out the process of converting back and forth with aspartate
because there are no oxaloacetate transporters
how does the glycerol-3-phosphate shuttle work for transporting NAD/NADH into the mitochondrial matrix?
- NADH in the cytosol is converted to NAD during synthesis of glycerol-3-P using Cystolic Glycerol 3-P DH
- Glycerol-3-P moves into the intermembrane space
- Glycerol-3-P is oxidized by mitochondrial G3P DH (creating FADH2)
- Dehydroxyacetone phosphate leaves the mitochondria
- Glycerol 3-P acts like complex two of the ETS and transfers its FADH2 electons to Ubiquinone
What is the main difference between the malate aspartate shuttle and the Glycerol-3-P shuttle
the malate aspartate conserves the energy better because it takes an NADH in the cytosol and gets an NADH in the mitochondrial matrix.
the glycerol 3 phosphate shuttle doesn’t conserve energy as well because it takes an NADH in the cytosol and gives you an FADH in the mitochondria.
how much less energy do you get from the glycerol-3-phosphate shuttle than the malate aspartate shuttle
1 less ATP
