LS 3 Lecture 2

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LS 3 Lecture 2
2012-01-18 22:35:30
LS week DNA

Week 1/2 of LS 3
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  1. Gene
    The entire DNA sequence required to encode a functional polypeptide (protein) or RNA
  2. Cistron
    An old name for gene
  3. Pseudogene
    A DNA sequence that looks like a gene but is not transribed
  4. Promoter
    • - the DNA sequence that determines transcription (RNA synthesis) initiation
    • - always at the 5' end of the transcribed region
  5. Transcription regulatory sequences
    Sequences that are not promoters but can also regulate transcription
  6. Transcribed sequence
    The sequence that is actually transcribed into RNA
  7. Terminator
    • - The sequence that terminates transcription
    • - it always occurs at the 3' end
  8. Poly vs. Monocistronic
    • Poly (prokaryotic genes): one promoter directs the synthesis of a mRNA that can encode more than one protein
    • Mono (eukaryotic genes): ...only one protein
  9. Introns vs. Exons
    Introns are non-coding sequences that are transcribed into RNA, but never translated into a protein. Exons are eventually translated.
  10. Why is ssDNA stable in alkaline solution, but not RNA?
    The 2' hydroxyl group makes RNA unstable in alkali because it can attack the phosphodiester bonds of the RNA chain and break it (hydrolysis) into nucleotide monomers
  11. Two common secondary structures of RNA
  12. mRNA function and structure
    • "message RNA"
    • - template for protein translation
    • - usually a linear structure
  13. tRNA function and structure
    • "transfer RNA"
    • - brings amino acids for the translation reaction
    • - has a unique clover-leaf structure
  14. rRNA function
    • "ribosomal RNA"
    • - RNA molecules found in ribosomes, which are the protein synthesis apparatus
  15. What special modifications does eukaryotic mRNA have?
    A cap at the 5' end and a poly(A) tail at the 3' end
  16. Describe the bond that holds together two amino acids
    It is a covalent peptide bond
  17. How stable is a peptide bond?
    How can you break one?
    Stable, but can be broken by acid hydrolysis or proteolysis
  18. Components of an amino acid
    • - amino group
    • - carboxyl group
    • - side chain (R)
  19. Hydrophobic amino acids
    Alanine (Ala), Valine (Val), Isoleucine (Ile), Leucine (Leu), Methionine (Met), Phenylalanine (Phe), Tyrosine (Tyr), Tryptophan (Trp)
  20. Hydrophilic amino acids
    Lysine (Lys), Arginine (Arg), Histidine (His), Aspartate (Asp), Glutamate (Glu), Serine (Ser), Asparagine (Asn), Threonine (Thr), Glutamine (Gln)
  21. Special amino acids
    • Cysteine (Cys)
    • Glycine (Gly)
    • Proline (Pro)
  22. Function of:
    • Degrades proteins
    • adds phosphate to a protein
    • removes phosphate
  23. Function of:
    • Synthesize RNA
    • DNas and RNase
  24. How can you measure protein function? (three ways)
    • Affinity - binding strength
    • specificity - binding preference
    • velocity - speed of reactions
  25. Antigens
    Antibody-inducing agents
  26. Epitope
    The region of an antigen recognized by the antibody
  27. Complementarity Determining Region (CDR)
    The region of an antibody that binds to an antigen
  28. How do enzymes catalyze chemical reactions?
    • - bringing two substrates together at the right orientation
    • -changing +/- charges of the substrate
    • -inducing tensions in chemical bonds of the substrate molecule
  29. The Central Dogma states that...
    The flow of genetic information is always from DNA to RNA
  30. Transcription is catalyzed by...
    RNA polymerase
  31. Transcription is the process by which...
    RNA is synthesized
  32. What are the components needed for translation?
    • - mRNA
    • - tRNA
    • - ribosome
  33. Semiconservative rule
    DNA replication results in a newly synthesized dsDNA that contains one parental strand and one new strand
  34. DNA replication is catalyzed by...
    DNA polymerase
  35. Three types of point mutations
    • - Nonesense (change of amino acid codon to the stop codon)
    • - Missense (change from one amino acid to another)
    • - Silent (change to a different codon for the same amino acid)
  36. Sickle cell anemia
    - person inherits two mutant alleles, resulting in a mutant HbS protein that cause their erythrocytes to change shape, which results in anemia
  37. How are sickle cells different from normal red blood cells?
    • - they are sickle-shaped and rigid
    • - they only last about 10-20 days instead of 4 months
  38. Describe the HbS mutation
    A point mutation in the beta-globin gene causes the glutamate codon GAG to change into the valine codon GUG