Transcription

Question 1

What is Step 1?

Answer 1

1) 5’ TATA 3’ is the initiation code. Transcription factors bind at this site which is upstream of the actual gene (towards 5’end). Promotor regions are also upstream of the actual gene. This attracts RNA polymerase to start mRNA production. RNA polymerase separates DNA strand.

Question 2

What is Step 2?

Answer 2

2) RNA polymerase starts mRNA production. RNA polymerase separates DNA strand. RNA polymerase continues picking up base pairs and copying them onto complementary RNA strand

Question 3

What is Step 3?

Answer 3

3) methyl guanine ‘cap’ added to 5’ end (Methylguanine bonded with 5-5 triphosphate linkage to stabilise the mRNA).

Splicing occurs

At the 3’ end stop codon AAUAA causes cleavage of the mRNA. This is followed by adenylation (around 200 adenine added)

Question 4

In transcription what is the template strand and what is the coding strand?

Answer 4

Coding strand is 3 to 5, template is 5 to 3.