Transcription

Question 1

Transcription

Answer 1

Occurs when a segment of DNA acts as a template to direct the synthesis of a complimentary sequence of mRNA, with the enzyme RNA polymerase

Question 2

Transcription Process

Answer 2

1) DNA Helicase breaks the hydrogen bonds in specific sections of DNA
2) DNA bases in the template strand in this section are exposed
3) RNA polymerase attaches to the template strand of DNA and moves along it inserting the complementary base pairing (A,U,C,G)
4) Temporary hydrogen bonds are formed between the complementary base pairs
5) When RNA Polymerase reads a stop codon on the DNA it detaches
6) The free mRNA nucleotides join together by phosphodiester bonds, forming a sugar phosphate backbone
7) The mRNA strand detaches (H bonds break) and is called pre-mRNA (Contains both introns and exons)
8) The DNA will then re-zip and rewind

Question 3

Post-Transcriptional Modifications

Answer 3

Eukaryotes:
-Introns are removed from the pre-mRNA through splicing, to form mature mRNA

-The mature mRNA leaves via the nuclear pores