Topic 9: DNA structure Flashcards
what do DNA and nucleic acid (DNA and RNA) all have in common
they are polynucleotides
what are nucleic acids
DNA and RNA
linar polymers of nucleotides
what is the structure of a nucleotide
pentose sugar connected to base and phosphatew
what is the structure of a nucleoside
pentose base and sugar
what are the two types of pentose sugar and where are they found
ribose in RNA, deoxyribose in DNA
how does structure of types of pentose sugar differ
in ribose - c2 is hydroxyl, in deoxyribsose on C2 just as hydrogen
what are the two types of nitrogenous base
purine and pyrimidine
what bases are purines
guanine
adenine (AG)
what bases are pyrmidines
cytosine, uracil, thymine (CUT)
what is the difference between purines and pyrmidines
purines are 2 rings, pyrmidines one ring
where is thymine found
only in dna
where is uracil found
only in RNA
what are the two types of nucleoside
nucleoside (RNA) and deoxyribonucleoside (DNA)
what can nucleosides be used for
precursors for nucleotides
phosphorylated to form them (C5 = phosphate)
if the base of a nucleoside was adenosine what would the nucleoside be called
deoxyadenosine monophosphate
what are the bases
A, T, C, G, U
what are the nucleosides
adenosine, guanosine, uridine, cytidine (RNA)
deoxyadenosine, deoxyguanosine, deoxythymidine, deoxycytidine (DNA)
what are the nucleotides
AMP, GMP, UMP, CMP (RNA)
dAMP, dGMP, dTMP, dCMP (DNA)
what are the monomers of polynucleotides
nucleotides
how are nucleotides bonded together
phosphodiester bond
chain has a 5 to 3 prime polarity
5 prime end = phosphate, 3 prime end = hydroxyl groups
how does base pairing work
NH3 - delta positive, C=O = delta negative on O which attract each other to form hydroge bonds
how many Hydrogen bonds in G-C
3
how many hydrogen bonds in A-U
2
what is base pairing between
between pyrimindine and purine
how many hydrogen bonds in A-T
2
how is a secondary structure formed
one in 5-3 prime end from top to bottom
one in 3-5 prime end from bottom to top
antiparallel strands bring complementary base together
what is secondary structure
double stranded
how are sugars and phosphates held together in single strand of DNA
covalent bonds
how are complementary base pairs held together
hydrogen bonds and london forces as tightly stacked
what is the tertiary structure of DNA
right handed double helix with anti parallel strands
major groove - bases accessible
minor groove - bases hidden in helix
what is the quarternary structure of DNA
from double helix to nucelosomes
nucleosomes to hetero and euchromatin
how is a single stranded nucleic acid depicted
5 end sugar, phosphate, S, P, S, P 3 end
5 prime ACCT 3 prime
5 prime end is on the
left
how is a duplex sequence depicted
double strand antiparallel so
5 prime ACCTCG 3 prime
3 prime TGGAGC 5 prime
(may only be top strand as know what bottom strand will be)
