In benzene the Pi electrons are delcoised whereas in an alkene the Pi electrons are loated inbetween 2 carbon so it has a higher electon density, this means bromie more attracted to alekenes
- takes place in the nucleus
- DNA double helix unzip/ unwind strands are broken this reaction is catalysed by the enzymes DNA HELICASE
- The exposed DNA Nucleotides complenary base pairs with free activated RNA nucletioides in the nucleus’s
- Enzyme RNA POLYMERASE joins RNA nucleotide together in a condensation reaction.
- m-RNA detaches from the DNA
- m-RNA Protected is completed to the DNA coding strand
- m-RNA leaves the nucleus though the pore in the nucleus envelope and attaches to the ribosome in the cytoplasm.
Steps of Transcription
Transcription takes place in steps: initiation, elongation, and termination.
- Initiation is the beginning it when the enzymes catalyst RNA polymerase which makes the DNA to unwind
- This helps m-RNA
- Elongation is the when you add more nucleotides to the mRNA strand.
- Termination is the ending of transcription, its when the rna polymerase meets a STOP CODON.
- Purines – 2 double rings
- – GUANINE
- Pyrimidines – 1 ring
- Order of bases contains the ‘code’ to make proteins
- In a DNA molecule it must be made of a purines and a pyrimdines which makes it an exact length g if it was 2 purines it would be too long and if it was 2 pyrimidines it would be too short!