termination signal: The intrinsic terminator sequence An inverted repeat of GC-rich sequence followed by 4 or more adenines. The transcribed RNAforms stem-loop structureat inverted repeats via internal base pairing The formation of this stem-loop structure disrupts hydrogen bonding between RNA uracils and DNA adenines at site of transcription (weak because only 2 H-bonds between A and U as compared to 3 between G and C) As a result, RNA is released from the DNA templateWhat is an inverted repeat? A sequence of several bases in double-stranded DNA that is repeated in an inverted fashionExample:•5'.....GCCAGTGG........CCACTGGC....3'•3'.....CGGTCACC........GGTGACCG....5' (template strand)transcribed RNA: 5'.......GCCAGUGG.......CCACUGGC.....3'Consequently there are internal sequences in the transcribed RNA that are complementary and can therefore base pair to form a stem-loop structureSome termination sequences lack the series of adenines which are transcribed in to URACILS on the RNA. The RNA in such situations needs assistance from a specific
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