lecture 5 Flashcards
dna structure and properties pt.2
what is the shape of DNA?
double helix of two complementary polynucleotide chains
what is a two-ringed heterocyclic nitrogenous base?
purine
how many atoms are in the ring structure of a purine atom?
9
what is a single-ringed nitrogenous base?
pyrimidine
how many atoms are in the ring structure of pyrimidine atom?
6
what are the TWO purines?
adenine, guanine
what are the THREE pyrimidines?
cytosine, thymine, uracil
what is a nucleoside comprised of?
nitrogenous base and deoxyribose sugar
what is a nucleotide comprised of?
nitrogenous base, deoxyribose sugar, phosphoric acid
what type of bond holds together the nitrogenous base and the deoxyribose sugar?
N-glycosidic bond
what type of bond connects the deoxyribose sugar to the phosphate group?
phosphodiester bond(5’carbon to 3’carbon)
what type of configuration is favored by purines?
anti
what type of configuration has a role in the creation of Z-DNA in purines?
syn
what type of bond is the phosphodiester bond on the 5’ carbon end?
covalent
what type of bond is the phosphodiester bond on the 3’ carbon end?
hydrogen bond
how many hyrdogen bonds connect an adenine to a thymine?
2 hydrogen bonds
how many hydrogen bonds connect a cytosine to a guanine?
3 hydrogen bonds
what is the hydrated form of DNA known as?
B-DNA
what type of DNA has a right-handed double helix and has bases that are stacked?
B-DNA
what is the unhydrated form of DNA known as?
A-DNA
what type of DNA is wider and shorter than B-DNA?
A-DNA
what type of DNA has a right-handed double helix and has bases that are tilted inwards?
A-DNA
what configuration are the bases of A-DNA and B-DNA generally?
anti configuration
what type of DNA is found most often in protein binding to specific nucleic acids?
Z-DNA
what characteristics does the form of Z-DNA have?
left-handed helical formation with a zig-zag pattern
what type of DNA often has repeating purine-pyrimidine sequences?
Z-DNA
what kind of base configuration is found in Z-DNA?
BOTH anti and syn
