BHCM 307 Exam II

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BHCM 307 Exam II
2013-10-26 16:14:51
Not included Quiz III

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  1. Explain why the genetic code is degenerate
    • because it is redundant
    • most aa have more than one codon
    • first 2 nucelotides are most important
  2. Start and Stop codons
    • Start is AUG (Met)
    • 3 stop codons no aa listed
  3. Wobble
    • because third base pair isn't as important
    • There for several tRNAs for each aa
    • Inosine can bond with A, U, or C = wild card
  4. Check pH question
  5. aminoacyl- t RNA sythetases
    • at least one sythetase for each aa
    • catalyze reaction
    • aa + ATP -> aminoacyl-AMP +PPi
    • aminoacyl-AMP + tRNA -> AMP + aminoacyl-tRNA
    • they are specific to the aa and tRNA
    • aa linked to 3' hydroxyl
  6. Open Reading Frame
    • ORF
    • sequence starting with AT(U)G and ending with a stop codon
  7. Translation In Eukaryotes
    • ATG is usually the initiator codon
    • 1 mRNA = 1 protein
  8. Shine-Dalgarno Sequence
    • sequence that binds to ribosomal RNA and initates translation by makin an initiation complex
    • In prokaryotes
    • can be anywhere in mRNA = can code for more than one protien
  9. Chain initiation in Prokaryote
    formation of initiation complex (mRNA, ribosomes subunits, initiation factors, fMet-tRNA)
  10. Chain Elongation in Prokaryote
    • Ribosome attaches to P site and A site
    • Step 1: aminoacyl-tRNA binds to A site and anticodon loop binds to next codon
    • Step 2: peptide chain moves from P to A site
    • -catalyzed by peptidyltransferase
    • -forms new peptide bond
    • -proteins synthesized N to C
    • Step 3: release tRNA at P site and translocation of peptidyl-tRNA from A to P
  11. Chain termination in Prokaryotes
    • Release factors bind to A site with a stop codon
    • peptide is released from final tRNA hydrolysis
    • mRNA is relased
    • ribosomal subunits dissociate
  12. cloning
    isolating the gene in a form that can be replicated in abundance in another host
  13. nucleases
    • enzymes that degrade nucleic acids
    • exonucleases: degrade from 5' to 3' end
    • endonucleases: degrade nucleic acids by¬† cleaving at specific internal sequences
    • Developed by bacteria to kill virus DNA
  14. Restriction endonucleases
    • cut DNA at specific sequences
    • usally palindromes
    • hydrolyze the phosphodiester backbone
  15. recognition sequence
    • place were enzymes cleave
    • usually even numbered
    • size determines frequency
    • longer more rare 6 bp = relatively rare
  16. Sticky ends
    • can rebind with H-base pairing
    • weak and easily comes apart
    • DNA ligase can can reform the phosiester covalent bond and make it strong
    • It is like molecular glue
  17. Vectors
    • what DNA can be cloned into
    • Used to use bacteriophages to make single strand DNA
    • Now use plasmids circular DNA
  18. Plasmids
    • Circular DNA
    • In bacteria
    • Carry their own origin of replication
    • carry antibiotic resistance genes
    • many convenient restriction enzyme sites for cloning
    • Engineered more sites
  19. DNA RNA both neither
  20. DNA RNA both neither
  21. Purines
    hexose and pentose
  22. pyrididines
  23. DNA replication begins at the
  24. peptidyltransferase
    • enzyme encoded by ribosomes
    • makes new peptide bond
    • fMet transfers
  25. formation of intitation complex
    • RNA
    • small ribosomal sub units
    • Initiation factor
    • fMet-tRNA
    • large ribosomal sub unit
  26. cDNA
    • copy DNA
    • complementary DNA
    • synthesized in vitro by reverse transcriptase using mRNA as a template
    • represents genes expressed in a cell or tissue
    • There are cDNA libraries
  27. cloning DNA in Plasmid vectors
    • digest wanted DNA and plasmid with same restriction enzyme
    • mix DNA and allow sticky ends to anneal
    • add DNA ligase and ATP
    • add mixture to antibiotic sensitive bacteria that can take up the DNA
    • grow in antibiotic
  28. DNA electrophorese
    • DNA is negatively charged
    • smaller moves faster
    • ethidum bromide- makes it floress
  29. dideoxy nucleotides
    • don't have the 3' or 2' OH
    • therefore end the sequence
    • if you know where it ends you can figure out the sequence
  30. microray v. northern blot
    • microray: does thousands at once
    • attaches them to a chip
    • tags and floresses them
    • northern blot:puts it on a nylon sheet
    • hybridizes it with DNA probe
  31. PCR
    • uses taq polymerase
    • heat to 94 for 30 seconds
    • cool to ~55 for 30 seconds
    • heat to 74 for how ever long you want the bp