FA Biochem 1

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FA Biochem 1
2015-01-21 15:40:01

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  1. Transition
    purine to purine (e.g., A to G) or pyrimidine to pyrimidine (e.g., C to T).
  2. Transversion
    purine to pyrimidine (e.g., A to T) or pyrimidine to purine (e.g., C to G).
  3. Missense and give an example
    • Nucleotide substitution resulting in changed amino acid (called conservative if new amino acid is similar in chemical structure).
    • example: Sickle cell disease
  4. Nonsense
    Nucleotide substitution resulting in early stop codon.
  5. Frameshift and give an example
    • Deletion or insertion of a number of nucleotidesnot divisible by 3, resulting in misreading of all nucleotides downstream, usually resulting in a truncated, nonfunctional protein.
    • example: Duchenne muscular dystrophy
  6. mRNA start codons
    AUG (or rarely GUG).
  7. mRNA start codons in Eukaryotes codes for
    Codes for methionine, which may be removedbefore translation is completed
  8. mRNA start codons in Prokaryotes codes for
    Codes for formylmethionine (f-met).
  9. mRNA stop codons
    UGA, UAA, UAG.
  10. RNA polymerases Eukaryotes 
    makes rRNA
    RNA polymerase I
  11. RNA polymerases Eukaryotes 
    makes mRNA
    RNA polymerase II
  12. RNA polymerases Eukaryotes 
    makes tRNA
    RNA polymerase III
  13. tRNA structure
    • 3' end has CCA
    • T-arm
    • D-arm 
    • Anti-codon loop
  14. T-arm in t RNA?
    contains the TΨC (thymine, pseudouridine, cytosine) sequence necessary for tRNA ribosome binding.
  15. D-arm: in tRNA?
    contains dihydrouracil residues necessary for tRNA recognition by the correct aminoacyl tRNA synthetase
  16. Acceptor stem: tRNA
    the 3′ CCA is the amino acid acceptor site
  17. Rough endoplasmicreticulum 2 functions
    • 1)Site of synthesis of secretory (exported) proteins
    • 2) N-linked oligosaccharide addition to many proteins.
  18. where do u find Nissl bodies? what is the func?
    • RER in neurons
    • synthesize peptide neurotransmitters for secretion
  19. what cells are rich in RER?
    • Mucus-secreting goblet cells of the small intestine and antibody-secreting plasma cells
    • are rich in RER.
  20. SER function?
    Site of steroid synthesis and detoxification of drugs and poisons. Lacks surface ribosomes.
  21. where do u find SER mostly?
    Liver hepatocytes and steroid hormone–producing cells of the adrenal cortex and gonads are rich in SER.
  22. Golgi func
    distribution center for proteins and lipids from the ER to the vesicles and plasma membrane. Modifies N-oligosaccharides on asparagine.  Adds O-oligosaccharides on serine and threonine. Adds mannose-6-phosphate to proteins for trafficking to lysosomes.
  23. I-cell disease defect in
    phosphotransferase Ž failure of the Golgi to phosphorylate mannose residues (i.e.,  mannose-6-phosphate) on glycoproteins Ž proteins are secreted extracellularly rather than delivered to lysosomes.
  24. I-cell disease cc
    coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes. Often fatal in childhood
  25. Signal recognition particle (SRP) func
    Abundant, cytosolic ribonucleoprotein that traffics proteins from the ribosome to the RER. Absent or dysfunctional SRPŽ proteins accumulate in the cytosol.
  26. AB against SRP --> what disease?  
    also Anti-Jo-1 and anti-Mi-2
    polymyositis and dermatomyositis
  27. Vesicular trafficking proteins
    • COP I 
    • COP II
    • Clathrin
  28. Vesicular trafficking proteins 
    COOP I func?
    Golgi Ž--> Golgi (retrograde); GolgiŽ --> ER.
  29. Vesicular trafficking proteins
    COP II func?
    • Golgi -->Golgi (anterograde);
    • ERŽ --> Golgi.
  30. Vesicular trafficking proteins
    clathrin func?
    Clathrin: trans-Golgi -->Ž lysosomes; plasmamembrane -->Ž endosomes (receptor mediated endocytosis [e.g., LDL receptor activity]).
  31. Peroxisome
    Membrane-enclosed organelle involved in catabolism of very-long-chain fatty acids, branched-chain fatty acids, and amino acids.
  32. Proteasome
    Barrel-shaped protein complex that degrades damaged or ubiquitin-tagged proteins.
  33. Defects in the ubiquitin-proteasome system have been implicated in some cases of
    Parkinson disease.
  34. Drugs that act on microtubules
    • (Microtubules Get Constructed Very Poorly):
    • ƒƒMebendazole (anti-helminthic)ƒƒ
    • Griseofulvin (anti-fungal)
    • ƒƒColchicine (anti-gout)ƒƒ
    • Vincristine/Vinblastine (anti-cancer)ƒƒ
    • Paclitaxel (anti-cancer)
  35. Molecular motor proteins— Dynein
    Dynein = retrograde to microtubule (+ --> Ž -).
  36. Molecular motor proteins Kinesin
    Kinesin = anterograde to microtubule (- -->Ž +).
  37. Immunohistochemical stains for intermediate filaments
    • 1-Connective tissue
    • 2-Muscle
    • 3-Epithelial cells
    • 4-NeuroGlia
    • 5-Neurons