lipid unique to the mitochondrial inner membrane
abnormal mitochondria with a disorganizedappearance and crystal structures within
voltate-dependent anion channels (VDACs
large non-selective pores on the outer membrane that allow meovement of anions such as phosphate, chloride, pyruvate, citrate, and adenine nucleotides
beta barrel structure hints a bacterial origins of mitochondria
mitochondria contain their own DNA and tRNAs
proteins need to bew synthesized in the cytoplasm and then transported into mitochondria
only 13 subunits of the ETC are expressed in the mitochondrial genome
import of proteins into the mitochondrion
must have amphipathic
recognized by protein complexes TOM and TIM (transport outer and transport inner membrane
proteins transported as a linear peptide
the process of using the energy from the electrochemical potential gradient generated by oxidation in the ETC to create ATP from ADP
Describe the electron flow through the ETC.
oxygen is the best electron receptor and has the largest positive reduction potential
more energy is released from the oxidation of NADH by O2 than the oxidation of FADH2 by O2 because NADH has a more negative reduction potential than FADH2
accepts a free proton plus the hydride ion carried by NADH, has an Fe-S center
does not span the membrane, contains succinate dehydrogenase
takes electrons from FADH2 and passes it onto CoQ
Coenzyme Q or ubiquinone
mobile carrier that accepts electrons from complexes I and II and donates them to complex III
linked to a 50 carbon lipid that allows it to diffuse through the membrane
cytochrome proteins have bound heme with an iron atom
electrons are transfered to cytochrome c
cytochrome c oxidase
complex passes electrons from cytochrome c to final electron acceptor O2
heme a, b, and c
heme a - long isoprenoid tail that can bind to proteins
heme b - more loosely bound
heme c - covalently attached to alpha helices
iron int he middle important for electron transport because can be oxidized from ferric to ferrous state and back
a protein that acts like a motor to add phosphates onto ADP to make ATP, uses the proton motive force
couples energy of proton movement with conformational changes to carry out the reaction
adenine nucleotide translocase (ANT)
exchanges ATP and ADP in a 1:1 exchange
Name the five major mitochondrial inner membrant transporters.
ATP-ADP translocase, dicarboxylate carrier, tricarboxylate carrier, pyruvate carrier, phosphate carrier
What are the two methods of transporting electrons into the mitochondria?
glycerol 3-phosphate shuttle and malate-aspartate shuttle
Describe the glycerol 3-phosphate shuttle.
major shuttle in most tissues
Describe the malate-aspartate shuttle
cytosolic NADH is necessary for shuttle function
Describe the creatine phosphate shuttle.
muscle needs high ATP, needs a way to keep cytosolic ATP low but also store energy for action
prevents ATP from being used up by other processes
mitochondrial permeability transition pore
mitochondria become more permeable to small molecules, leads to mitochondrial swelling and cell death through apoptosis or necrosis
uncoupling proteins (UCP)
found in the inner mitochondrial membrane, creating a proton leak without generation of ATP
energy is released as heat, up to 20% of adult resting metabolic rate is due to energy expended to restore proton gradients lost to UCPs
babies have brown fat that have UCPs to generate heat
compound that can uncouple OXPHOS because it transfers protons across the inner membrane down their concentration gradient
How do the following inhibitors affect the ETC? - cyanide, carbon monoxide, hydrogen sulfide, and sodium azide
bind to the iron in the heme of the cytochrome aa3 component of cytochrome oxidase, preventing electron transfer to O2
How does antimycin affect the ETC?
it binds to cytochrome c reductase in complex II, inhibiting the oxidation of CoQ in the electron transport chain of oxidative phosphorylation
Howe do barbituates such as Amytal and Rotenone affect the ETC?
inhibit the transfer of electrons from iron-sulfur centers in Complex I to CoQ
How does atractyloside affect the ETC?
inhibits the ADP-ATP transporter in the inner membrane
How does oligomycin affect the ETC?