biochem 314 U6

  1. How is dietary cholesterol taken into the body
    packed into chylomicron with fatty acids and glycerol, travels to  fatty acid target cell in chylomicron, fatty acids and glycerols deposited, cholesterol repackaged into chylomicron remnant and sent to liver.
  2. what is synthesis of cholesterol in the body called
    de novo
  3. how does caloric intake affect de novo synthesis
    increase in calories makes increase in cholesterol synthesis because insulin works as an acitvator to the transcription of the HMGCoA reductase enzyme
  4. what is the committed step of cholesterol synthesis
    HMGCoA + 2 NADPH --> Melavonate + 2 NADP+
  5. endogenous / hepatic absorption of lipids
    • FA TG Cho into VLDL
    • VLDL to target cell, drop off FA TG
    • LDL to target cells, receptor endocytosis drop off Chol
    • Nascent HDL returns to Liver, receptor endocytosis
    • OR LDL returns to liver for receptor endocytosis
  6. draw ribose
    • pentagon, O at top, clockwise:
    • CHOH
    • CHOH
    • CHOH
    • CH, CH2OH
  7. draw 2- deoxyribose
    • pentagon with O at top, clockwise
    • CHOH
    • CH
    • CHOH
    • CH, CHOH
  8. How are the pyrimidines alike 
    • all have hexagon structure
    • NH at the 6 oclock  
    • =O at the 8 oclock
    • double bond inside ring between 2 and 4oclock
  9. How are thymine and uracil similar and different from each other
    • both have 
    • =O at 8 oclock
    • =O at 12 oclock
    • NH at 10 oclock

    difference is thymine has an extra CH3 off the 2oclock carbon
  10. How is cytosine different from the other pyrimidines
    • only N at 10 oclock (instead of NH)
    • NH2 at 12 oclock (instead of =O)
  11. how are the purines alike
    • hexagon with right side pentagon
    • pentagons are identical with N at top point = to rt side C and NH at bottom point
    • both have N at bottom of hexagon
  12. How are adenine and guanine different
    • the 8 oclock adenine is blank, guanine has attached NH2
    • the 10 oclock adenine has N, guanine has NH
    • the 12 oclock adenine has NH2, guanine has =O
  13. what is the order of the 8, 10, and 12 oclock positions of the hexagon on guanine
    • NH2
    • NH
    • =O
  14. what is the order of the 8, 10, and 12 oclock on cytosine
    • blank
    • N
    • NH2
  15. what happens to LDL after they are endocytosized
    catabolized by lysosomes, LDL receptors recycled, repackaged as HDL and returned to liver
  16. function of HDL
    return excess cholesterol to liver for bile excretion
  17. FULL central dogma of genetics
    DNA -(transc)->PremRNA-(proc)->mRNA-(transl)->protein
  18. how do nitrogenous bases attach to sugar in nucleic acids
    the bottom NH and the 1'C perform dehydration synthesis so N is directly bonded with the 1'C
  19. which carbon does the phosphate group attach to on the sugar of a nucleic acid
    5' carbon
  20. how are nucleic acid polymers elongated
    • 1. a template strand is required
    • 2.. a primer strand (only needed inDNA) is formed
    • 3. appropriate polymerase uses the high energy triphosphate of the nucleoside triphosphate to bond the closest phosphate group to the 3'C of the nucleotide on the primer
  21. histone (octamer)
    a set of 8 chromosomal positively charged proteins that dna wraps around to keep its negatively charged phosphate groups from repelling each other when they try to package
  22. nucleosome
    the wrapped, neutral structure of dna around histone octamer
  23. 5' to 3' synthetic activity
    • addition of DNA to fill in blanks left by the excise of RNA primers during DNA replication
    • performed by DNA polymerase
  24. 3' to 5' exonucleolytic activity
    editing step of removing improperly paired nucleotides or tautomeric nucleotides
  25. 5' to 3' nucleolytic activity
    removal of RNA primers from daughter strand of DNA replication
  26. chain polarity
    one end of the chain has the 5' phosphate, the other has the 3' hydroxyl group. all are laid head to toe
  27. tautomeric forms
    nitrogenous bases of nucleotides with hydrogens that have changed locations and can base pair with other nucleotides
  28. helicase
    separates hydrogen bonds of the double stranded DNA
  29. single-stranded DNA proteins
    • prevent the two separated strands of dna from rejoining and
    • protects the ssDNA from reacting with other chemicals
  30. primase
    enzyme that creates a shrot RNA primer for the DNA polymerase to begin from
  31. DNA polymerase
    enzyme that adds nucleotide residues to the RNA polymerase and then to each nucleotide. It catalyzes the 3'-5' phosphodiester linkage by utilizing the triphosphate of the nucleotide triphosphates
  32. DNA ligase
    • used to "patch together" repairs or areas of RNA primer removal. catalyzes the phosphodiester linkage in the backbones. 
    • This is needed because the nucleotide residues are monophosphates, so not carryin the energy of a triphosphate.
  33. small nuclear RNA snRNA
    splices pre-mRNA to prepare it for use by ribosomes
  34. small nucleolar RNA snoRNA
    direct processing of rRNA
  35. microRNA miRNA
    increases expression of mRNA
  36. Transcription
    • RNA polymerase binds to PROMOTOR
    • RNA polymerase elongates the complementary strand
    • 5' end may be capped
    • 3' has poly A tail attached
    • splicing/maturation by snRNA
  37. TFIID and TFIIB
    upstream transcription factors that bind to the 5'TATA3' box and signal to RNA polymerase where the start of the gene is
Card Set
biochem 314 U6
study for unit 6 exam UW Madison Tom Neal summer session