DNA structure function Flashcards
define central dogma
how DNA self replicates, is transcribed into RNA and translated into a polypeptide
different between nucleoside and nucleotide
nucleoside: no phosphate group
nucleotide: po43-, nitrogenous base, pentose sugar
pentose sugar names in DNA and RNA?
In RNA, there is B-D-ribose; in DNA, there is B-D-2-deoxyribose (second carbon missing oxygen)
describe purine structure? what are they?
2 rings - 5/6 membered
adenine, guanine
describe pyrimidine structure? what they are?
one 6 membered ring; uracil, thymine, cytosine
describe polymerisation
condensation
requires polymerase
forms phosphodiester link
how long is DNA
10^6-7 nucleotides long
how was DNA discovered, and by who
1869: Miescher found substance from white blood cells rich in phosphorus and nitrogen; called it nuclein as it was found in nucleus
now we konw its dna
why does DNA have double helical shape
due to hydrophobicity of bases
describe how DNA double helix shape was discovered
• Rosalind Franklin did X ray crystallography of DNA
o X rays passed through DNA sample and photographed
• James Watson and Francis Crick explained the diffraction pattern through double helical structure
are DNA strands antiparallel
yes
how many bases per turn of helix
10-10.5
diameter of helix
2nm
describe major and minor groove
major groove a bit bigger than minor groove
describe hoechst dye
binds to minor groove, fluoreseces blue under UV light
