Nucleic Acid Structure Flashcards
nucloside
base+ ribose
nucleotide
base + ribose + phosphATE
Draw ribose
picture
draw deoxyribose
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bond between sugar and backbone
N-glycosidic
strong, but less so than C-N
DRAW adenine
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DRAW thymine
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DRAW cytosiine
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DRAW guanine
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DRAW uracine
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symbol for: nucleoside, nucleobase, nucleotide
N
ACTG
pN or Np
how many rotatable bonds in nucleotide?
which notable?
7
chi angle - between base and sugar- either anti or syn
base away from sugar or on top of
sugar pucker
so what?
sugar base not planar - C2; endo/exp (up/dow) C3’
given base and C5 up
changes “inclination of phosphate of
charactaristic - RNA and DNA tends toward endo
3 reading frames per strand bc
codons in triplets
charge per nucleotide
1 negative: shared between 2 ox in phos - pKALOW
5’ phosphate ends have 2: one with low PKA, other about 7 for enzymes to distinguish from s
RNA vs DNA
chemical stability
low chemical stability(acid/base) because of 2’ OH: perfectly oriented to undergo esterification to 3’ophosphate to break chain; DNA needs enzyme to do so.
+base-> backbone cleavag
+acid -> 3’-2’ migration (not bioactive) or depurination
DNA: good, but still acid labile
code for purine, pyrimidine
R, Y
isomer of bases: it makes a ___
base tautomer: o=c-nh to HO-c=n
ionization of adenine
PICTURE
ionizaon of guanine
PICTURE
responsible of depurination
depuination mechanism
PICTURE
most common DNA modification
methylation - post-transcriptional
6-me adenine in prok; 5-methyl cytosine both
prokaryotes: tag parental strand and self, restriction/modification system(in bateria-cut other dna)
5-methyl cytosine: 1st signal for silence by pack up into bundle