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In the following DNA sequence, transcribe into mRNA and translate into the appropriate...

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cenicienta | Valedictorian

Posted May 23, 2012 at 7:03 PM via web

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In the following DNA sequence, transcribe into mRNA and translate into the appropriate amino acid sequence. TAC/TTC/AAA/CCG/CGT/GGG/ATT.

 

Please explain how to do it (DNA to mRNA). Indicate an example of how a mutation could affect the characteristics of the protein.

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thilina-g | College Teacher | (Level 1) Educator

Posted May 23, 2012 at 7:39 PM (Answer #1)

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TAC/TTC/AAA/CCG/CGT/GGG/ATT

mRNA code can be derived as follows. In RNA instead of Thymine (T) you have Uracil (U)

mRNA string will have the complementary base pair to the DNA string

Complementary paring -

A-T here U

G-C

 

Therefore mRNA code is,

DNA    - TAC/TTC/AAA/CCG/CGT/GGG/ATT

mRNA -  AUG/AAG/UUU/GGC/GCA/CCC/UAA

 

To find the appropriate amino acid sequence we need a the codon code.

The amino acid squence is,

AUG is the start codon and it will represent Methionine.

UAA is the stop codon

 

Therefore the sequence is,

 

Methionine-Lysine - Phenylalanine-Glycine-Alanine-Proline (Stops)

 

Suppose the DNA code was changed like below through a mutation.

DNA    - TAC/TTC/ATA/CCG/CGT/GGG/ATT

mRNA -  AUG/AAG/UAU/GGC/GCA/CCC/UAA

Then the mRNA code also changes and protein will change as below.

Methionine-Lysine -Tyrosine-Glycine-Alanine-Proline (Stops)

 

Phenylalanine is replaced by tyrosine. Then the whole nature of the protein can be changed and it will have a different function.

 

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