Studied by 10 people
content on nucleic acid from bio unit A1.2
dna
genetic material of all living organisms
double helix
made of nucleotides
dna nitrogenous bases
adenine, thymine, guanine, cytosine
nucleotide structure
phosphate, sugar, base
nucleotide
single unit of nucleic acid
difference in rna and dna sugar
one less oxygen in dna sugar (on second carbon)
how is a strand of nucleotides joined
covalent bonds between phosphate and sugar (phosphodiester bond)
sugar-phosphate backbone
condensation reactions
anabolic - join monomers to make polymers
endothermic - require energy to take place
creates covalent bond
water is produced as byproduct
which bases are purines
adenine and guanine - larger bases with additional ring
which base are pyramindines
thymine, uracil, cytosine - single ring
complementary base pairing
each base will only line up properly with one other (a-t and g-c)
hydrogen bonds hold them together (2 for at and 3 for gc)
nucleosomes
regions of dna wrapped around 8 proteins called histones with an additional one to lock it into place
euchromatin
loosely bound nucleosomes to each other
can be transcribed
heterochromatin
tightly bound
