| Term | Definition |
|---|
| the function of mitochondria | generate ATP by oxidative phosphorylation via respiratory chain, allows 15 times more ATP to be generated than is produced by glycolysis alone |
| pyruvate is imported into mitochondria and oxidized by the O2 to | CO2 and H2O |
| mitochondria move around constantly and frequently | change their shape, fuse and then separate |
| frequently associated with ___________ and concentrated at sites of high _____ consumption | microtubules, ATP |
| inner mitochondrial membrane – | folds into cristae which increase surface area, Important for ATP synthesis- contains the proteins that make up the respiratory chain |
| intermembrane space | between inner and outer membranes, where the H+ are pumped from the inner membrane |
| matrix | large internal space within inner membrane that contains enzymes, mitochondrial genome, mitochondrial ribosomes, mitochondrial tRNA, all proteins fro metabolic events. |
| outer mitochondrial membrane | is permeable to molecule <5000 MW and has porins |
| release of intermembrane space proteins like cytochrome c occurs during | apoptosis |
| inner membrane proteins | proteins involved in ETC, includes ATP synthase |
| ATP synthase | converts ADP to ATP, via this enzyme complex, H+ enter from inner membrane space to matrix |
| The matrix also includes enzymes involved in | metabolism of pyruvate and fatty acids to acetyl CoA; citric acid cycle |
| How are cytosolic proteins targeted to specific locations in mitochondria? | . this is accomplished by protein translocators in mitochondrial membranes; multimeric membrane protein assemblies that catalyze protein transport |
| TOM complex | Transfers proteins across OUTER membrane |
| TIM complexes | Transfers proteins across INNER membrane |
| SAM complex | Helps fold proteins in OUTER membrane |
| OXA complex | Mediates insertion of inner membrane proteins that are made in mitochodrial matrix |
| cytoplasmic proteins that will enter mitochondria remain unfolded by interacting with other proteins | include chaperones of Hsp70 family |
| mitochondrial signal peptides | are 20-80 aa at amino terminus that signal protein to mitochondria and also has a α helix with + charged AAs |
| proteins associated with chaperones interact with | import receptors of TOM complex |
| passage of a protein into the matrix can occur through both membranes (inner and outer) at | contact sides, locations where the two mitochondrial membranes appear to be fused |
| release of polypeptides from Hsp70 family member requires | ATP hydrolysis |
| TOM-TIM coordination is needed to | get protein into mitochondria |
| translocation of positively charged signal peptide through TIM channel requires | membrane potential (electrochemical H+ gradient across inner membranes) |
| mitochondrial Hsp70 binds tightly to | import protein as it emerges from TIM translocator and releases the protein in an ATP-dependent step |
| imported proteins are passed over to mitochondrial Hsp60, which promotes | proper folding (requires cycles of ATP hydrolysis) |
| insertion of proteins into outer mitochondrial membrane- after translocation through TOM complex, β-barrel proteins bind to | chaperones in intermediate space, SAM complex then inserts unfolded protein into outer membrane and helps them fold properly |
| transport of proteins into inner mitochondrial membrane and intermediate space (several mechanisms) | only N-terminal signal sequence enters matrix space |
| hydrophobic amino acid sequence placed after N-terminal signal sequence acts as | a stop-transfer sequence, preventing further translocation across inner membrane |
| TOM complex pulls remainder of protein through outer membrane into | intermembrane space, signal sequence is cleaved off in matrix, hydrophobic sequences, released from TIM23, remain anchored in inner membrane |
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