GENETICS Processes Transcription

 

- Info:

- Transcription is process of synthesising messenger RNA, called mRNA from part of DNA.

- This tutorial is based on http://learn.genetics.utah.edu/content/begin/dna/transcribe.

 

- Example:

 

- Lets suppose that part of DNA sequence looks like this.

 

    

T

A

A

T

G

C

T

A

C

A

C

G

T

G

T

T

C

T

A

G

G

A

 

A

T

T

A

C

G

A

T

G

T

G

C

A

C

A

A

G

A

T

C

C

T

 

- Enzyme RNA polymerase binds to the DNA strand at a specific sequence of the gene called a promoter.

Then it unwinds and unlinks the two strands of DNA.

 

    

T

A

A

T

G

C

T

A

C

A

C

G

T

G

T

T

C

T

A

G

G

A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A

T

T

A

C

G

A

T

G

T

G

C

A

C

A

A

G

A

T

C

C

T

 

- Uses one of the DNA strands, lower one in this example. as a template for synthesising messanger RNA mRNA.

Adds new nucleotides to the strand attaching U to A, A to T, G to C and C to G.

Process continues until it encounters a termination sequence of bases (stop codon)

 

    

U

A

A

U

G

C

U

A

C

A

C

G

U

G

U

U

C

 

 

 

 

 

 

A

T

T

A

C

G

A

T

G

T

G

C

A

C

A

A

G

A

T

C

C

T

 

- Result is mRNA strand which looks just like upper DNA strand having U instead T.

 

    

U

A

A

U

G

C

U

A

C

A

C

G

U

G

U

U

C

U

A

G

G

A