BHCM 307 Exam II

  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
    • Image Upload 2
  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
    adenosine
    both
  20. DNA RNA both neither
    ribose
    RNA
  21. Purines
    hexose and pentose
  22. pyrididines
    hextose
  23. DNA replication begins at the
    origin
  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
Author
MRK
ID
241358
Card Set
BHCM 307 Exam II
Description
Translation
Updated