nucleic acids and chromosomes Flashcards
nucleic acid structure: explain the structure of DNA and RNA, list the bases found in DNA and RNA and indicate which ones are purines and which ones are pyrimidines
nucleotide and nucleoside
nucleotide: 1 (or more) phosphate on C5; deoxyribose sugar; nitrogenous base on C1 (B-glycosidic link); nucleoside: no phosphate group on C5
DNA structure
double stranded; deoxyribose sugar; phosphate on C5; nitrogenous base on C1 (B-glycosidic link)
RNA structure
single stranded; oxyribose sugar; phosphate on C5; nitrogenous base on C1 (B-glycosidic link)
DNA purines
A, G; 2 rings
DNA pyrimidines
T, C; 1 ring
RNA purines
A, G; 2 rings
RNA pyrimidines
U, C; 1 ring
primary structure of DNA chain
linear polymer of nucleotides; primary: 3’OH → PO4 2- → 5’OH (adjacent) so asymmetrical 3’ and 5’ ends; written from 5’ (free phosphate) to 3’ (free OH)
secondary structure of DNA helix
minor and major grooves; right-handed double helix; antiparallel strands; -ve PO4 2- on outside (3’ to 5’ and 5’ to 3’); base stacking increases stability; flat base plane perpendicular to helix
