SFP: mitochondria Flashcards
name the major structural components of mitochondria
outer membrane, inner membrane, inter-membrane space, matrix
describe the outer membrane
it contains porins, making it permeable to small molecules
describe the inner membrane
folded into cristae that contain ETC and ATP synthase. these help maintain the protein gradient
describe the matrix
has enzymes for TCA cycle and FA oxidation; also contains mitochondrias DNA< ribosomes, tRNAs, and calcium
what determines the concentration of mitochondria in a cell
the cells energy needs! cardiac muscle for example will have a lot of mitochondria
what is the general shape of cristae?
lamellar; steroid hormones have tubular ones. the length of cristae is related to how active and energy producing they are
how are mitochondria able to move
traveling along microtubules
what kind of issues are linked to problems with mitochondrial division?
diabetes and neurodegenerative disease
what is the presequence pathway
delivers matrix proteins and some inner membrane proteins
what are Tom and tim?
tom: translocase of the outer membrane
tim: translocase of the inner membrane
what is a presequence
a specific AA sequence that directs the protein to the mitochondria
what is an internal sequence
a hydrophobic targeting sequence that allows proteins to exit tim laterally to be inserted into the inner membrane
what are heat shock proteins
chaperones that protect proteins from degradation and help them fold
what is a matrix processing peptidase
enzyme in the matrix that snips off the presequence to allow for proper folding of a protein
describe the presequence pathway
- proteins are targeted to the outer mitochondrial membrane by binding of the presequence to tom
- protein passes through tom and inter the intermembrane space
- protein passes through tim in the inner membrane. process is driven by a gradient attracting positive charges
- if the protein has an internal sequence it will move laterally into the inner membrane. if not it enters the matrix.
- once in the matrix, the protein is driven into the mitochondria via a heat shock protein
- presequence is cleaved off. protein is folded.
describe the insertion of proteins into the outer membrane
- synthesized porin goes through tom
- tiny tim shuttle the porin to the SAM complex
- SAM complex inserts the porin
what are beta barrels
the porins on the outer membrane; often called VDAC. they transport small hydrophilic molecules like ATP, ADP, pyruvate
what is CPT1
enzyme that transports long chain FA into the intermembrane space from the cytosol
the inner membrane of the mitochondria is ___ to ATP, ADP, FA, Pi
impermeable
what is ANT?
transports one ATP out of the matrix in exchange for ADP from the intermembrane space
what is a Pi symporter
brings Pi and H into the matrix
what is a. pyruvate symporter
brings pyruvate and H into the membrane
what is a calcium uniporter
brings calcium into the matrix
what is CPT II
trantsports FAs from the intermembrane space into the matrix
