DNA the basics Flashcards
how do DNA strands run relative to each other
anti-parallel
what is found at the end of the 5’ side of DNA
phosphate
what is found at the end of the 3’ side
OH group
name the purines
adenine
guanine
name the pyrimidines
thymine
cytosine
uracil
what direction are DNA sequences written in
5’ to 3’
what RNA sequence will be generated from this DNA sequence
5’-AGTTGCACG-3’
3’-TCAACGTGC-5’
5’ AGUUGCACG 3’
what type of replication occurs in replication of DNA
semi-conservative replication
what is semi-conservative replication
each daughter strand contains one conserved strand and one new strand
where does DNA unwind
at the replication origin
where does DNA synthesis begin
at the replication forks
how are new bases linked to a replicating DNA strand
via a phosphate group to the 3’ OH group of the growing strand
what is released when new bases are added
pyrophosphate P207 4-
what catalyses DNA replication
DNA polymerase
what is the name of the fragments added to the lagging strand
what enzyme joins these fragments and through what process
Okazaki fragments
DNA ligase
‘backstitching’
what is proof reading
when DNA polymerase checks the previous base added is correct before adding a new base
what is mismatching
where DNA polymerase corrects a mistake if one has occurred
what is transcription
DNA —–> mRNA
transcription start site
where the copying of the DNA strand into RNA begins
TATA box site
signal for start of transcription
promoter
where transcription factors bind to regulate transcription
terminator sequence/ stop site
the signal for RNA polymerase to stop carrying the DNA template into RNA
describe the processing of mRNA
splicing to remove introns
(coding exons join to form mRNA)
addition of polyA tail and 5’ cap
(stability and export from the nucleus)
alternative splicing
different tissues can express different versions of the same RNA generated by alternative splicing
