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Question 1

Transcription

Answer 1

Initiation: When 6 general transciption factors come to promoter region of gene, transcriptional activator binds to enhancer on the DNA, attracts RNA polymerase to come unwind the DNA, seperates into two strands

Elongation: RNA nucleosides base pair with template strand. Triphosphate ribonuclosides join, forms pre mRNA

Termination: Elongation happens till stop codon. Polydentation occurs. Methylated guanine cap added.

Question 2

DNA replication

Answer 2

RNA primase produces short strand/primer to start the process
DNA polymerase then takes over and adds nucleotides to 3’ end of replicating strand , can only add nucleotides to the end of the 5’ strand
Triphosphate nucleosides get added when the inner most inter phosphate bond gets broken, and the two phosphates are released. This provides energy for the joining of the nucleotides
replication is continuous in leading strand, while in lag strand it is discontinuous and makes fragments which are joined by DNA ligase
Lagging strand must loop round to be replicated
Polymerase proofreads the forming strands