Bio exam part 2

  1. charge of the mitochondria matrix
    negative charge
  2. general characteristics of mitochondria presequence
    • usually n-terminus
    • hydrophobic 
    • positive
  3. steps to transport peptide to mitochondrial outer membrane
    • hsp70 binds hydrophobic presequence and goes to mitochondria
    • TOM-translocase of outer motichondrial membrane
    • SAM- refolds protein into outer membrane
  4. TOM
    translocase of outermitochondrial membrane
  5. SAM
    sorting assembly mechinery
  6. TIM
    translocon across inner mitochondrial membrane
  7. transport of peptide to mitochondria matrix
    • TOM to TIM23/17
    • MPP cleaves targeting sequence
  8. trasport peptide to innermitochondrial membrane
    • TOM to TIM 22 which export peptide into the membrane
    • signal not cleavable
  9. tiny TIMS
    • low molecular weight proteins that live in the intermembrane space
    • mostly chaperones and folding proteins
  10. transport peptide to intermembrane space
    • TOM to TIM 23/17
    • TIM to MPP cleave targeting sequence
    • TIM 44 transports sequence to intermembrane space
  11. Proteins and process involved in peptide transport into chloroplasts
    • TIC TOC proteins 
    • similar mechanism as mitochondria
  12. Endoplasmic reticulum
    • site of production and the beginning of processing of proteins that are not cytoplasmic
    • lipid production
    • small molecule production
  13. examples of ER processed proteins
    membrane and secreted proteins
  14. remember structure of ER
    paltes, rough ER, smooth tubular structures
  15. do all cell types have the same amount of smooth and rough ER
    naw son
  16. what does the smooth ER produce
    cholesterol, hormones, membrane phospholipids, drug detoxification
  17. structure of export domains in the ER
    regions in the ER that are branched so vesicle can bud and transport
  18. where is calcium stored
  19. proteins involved with manipulation and maintaining smooth ER structure
    • reticulons: alpha helical proteins assist in bending of plasma membrane and cause it to form tubular structure
    • atlastins: GTPases exist at the branch point, GTPase activity causes the fusion of 2 tubule membranes
  20. relationship between cytoskeleton and ER
    ER binds side of microtubules and can be moved as microtubules move
  21. how to get proteins into the ER
    cotranslational insertion governed by n-terminus signal sequence
  22. cotranslational insertion into the ER steps
    • free ribosome in cytoplasm starts translation
    • translated signal sequence binds SRP
    • SRP binds and inactivates a couple of elongation factors and pauses the ribosome
    • SRP diffuses to the ER and binds to SRP receptor and translocon
    • SRP and SRPR when in contacts hydrolyze their GTPs
    • SRP and SRPR dissociates from translocon Sec61
  23. proteins involved in transport of protein into ER lumen
    • powered by ribosome w/ chaperone help BiP
    • binds specific hydrophib portions and ratchet the polypeptide into the ER
    • other chaperones help with folding
  24. chemical characteristics of the ER
    really crowded, oxidizing environemnt, favorable for disulfide bonds
  25. transmembrane proteins in the ER
    • Type I: n-terminal in the ER, contains stop transfer sequence at the beginning
    • Type II: N-terminal in the cytoplasm, contains an internal start transfer sequence
  26. features of post-translational insertion
    • common in yeast, and bacteria
    • rare in vertebrates
    • usually small proteins
    • includes some tail-anchored
  27. where does disulfide bond formation takes place
    in the ER
  28. what enzyme catalyzes disulfide formation
    protein disulfide isomerases
  29. difference between lipids in the ER and golgi/plasma membrane
    • contains more unsaturated lipids (kinks)
    • more flexible
    • more dynamic, favors folding
  30. protein modifications that occur in the ER
    Glycosylation, disulfide bond formation, folding
  31. where do preassembled sugars attach in the ER
    attach to asparagine residues
  32. Relationship between protein degradation and sugars
    ER degrades sugars over time and eventually signals ERAD
  33. what events can signal ERAD
    • protein misfolding which leads to aggregations
    • overexpression, stress overload the ER
  34. ERAD
    • ER -associated degredation
    • mutants are translocated back through sec61 into the cytoplasm and proteolysis
  35. CTFR
    • cystic fibrosis (recessive gene)
    • chloride channel in the ER
    • mutation make protein stay in the ER
  36. HMG-CoA-reductase
    on of the last enzymes in biosynthesis of cholesterol
  37. hypercholersterolmia
    • result of over activity of HMG-CoA reductase
    • males too much cholesterol
  38. drug used for hypercholesterolmia
    statins- they inhibit HMG-CoA-reductase
  39. where does lipid production take place
    • on cytoplasmic leaflet of the ER bilayer
    • flippases flip the lipid enzyme
Card Set
Bio exam part 2