structure of a nucleotide
phosphate group
5 C sugar (dna-deoxyribose, RNA-ribose)
nitrogenous base (dna: A,T,G,C rna: A,U,G,C)
differences between dna and rna
5 C sugar: dna-deoxyribose; rna-ribose
DNA-double stranded; RNA-single stranded
DNA-thymine; RNA-uracil
4 dna bases and 4 rna bases
DNA: adenine, thymine, cytosine, guanine
RNA: adenine, uracil, cytosine, guanine
base pairing rules for DNA and RNA
DNA: adenine bonds to thymine; cytosine bonds to guanine
RNA: adenine bonds to uracil; cytosine bonds to guanine
chargaff’s rule
in a given sample of DNA, the amount of A=T and C=G
purines vs. pyrimidines
purines: double ring structure, adenine and guanine
pyrimidines: single ring structure, cytosine and thymine (also uracil in rna)
purines always bond to pyrimidines
rosalind franklin
used x-ray crystallography to determine the structure of dna
watson and crick
credited with discovering the structure of dna
structure of dna
sugar phosphate backbone; nitrogen bases form the “rungs”
all the bonds are covalent EXCEPT the hydrogen bonds holding the nitrogen bases together in the center
where replication occurs
the nucleus
template for replication
dna (both strands)
enzyme required for replication
dna polymerase (main enzyme; polymerizes dna nucleotides and proofreads)
helicase (unwinds dna double helix), primase (makes an rna primer)
final product of replication
exact copy of dna
error rate of replication
1 in 10,000,000,000 bases
definitions
helix: spiral
complementary base pairs: in dna, A bonds with T and C bonds with G
replication: copying dna
semi-conservative replication: at the end of replicatIon, each new DNA strand is made up of two strands; one is an old, template strand and one is a new strand
mutagen: anything that causes a mutation (example: UV light, some chemicals, radiation)