NUCLEIC ACID CHEMISTRY I Flashcards
two types of nucleic acids
deoxyribonucleic acid
ribonucleic acid
monomers of a polymeric nucleic acid
nucleotide
nucleotides (monomer) connected by _____________ bonds to form nucleic acid (polymer)
phosphodiester bonds
sugar puckering
prevalent in RNA and a form of DNA
produces shorter phosphate-phosphate distance resulting in a more compact helical conformation
C3 pucker
sugar puckering
in B-form DNA
C2 endo
purines
adenine guanine
pyrimidine
cytosine
thymine
uracil
a base linked to a sugar without a phosphate group
___________ are named by changing the nitrogen base ending to -osine for purines and -idine for pyrimidines
nucleoside
a ______– is named using the name of the nucleoside followed by the phosphate group
nucleotide
the base composition of DNA generally _______ from one species to another
varies
DNA specimens isolated from different tissues of the same species have the ______ base composition
same base
the base composition of DNA in a given species does not _________- with an organism’s age, nutritional status or changing environment
change
a sequence that is read the same way in either direction
palindrome
when the inverted repeat occurs within each individual strand of DNA
mirror repeats
hoogsteen pairing
triplex DNA
occurs readily for DNA sequences with a very high proportion of guanosine residues
tetraplex
tetraplex structure is involved in holding chromosome ends together during _________
mitosis
when DNA is ___________ it winds around itself to form interwound supercoil
negatively supercoiled
___________- supercoil (left hand direction), it coils around a protein core to form toroidal supercoil
positive
in the case of eukaryotes
linear DNA complexed with _________- histones to form nucleosomes
histones
in the case of eukaryotes
one nucleosome has ______________ histone molecules
8
______ histone facilitates the coiling of the beaded fiber into higher order structures
H1
