Explain how a deletion mutation in a strand of DNA can affect the primary, secondary and tertiary structures of the protein for which it codes.

A deletion in a strand of DNA would result in a frameshift mutation, where the other base pairs following the deletion would move 'to the left' which would change the base pairs throughout the rest of the strand of DNA. This would result in a different mRNA strand being formed by pairing with the mutated DNA strand during transcription. During translation at the ribosome, the tRNA molecules bonded to their respective amino acids would create a different amino acid sequence due to the altered mRNA sequence, this would effect the primary structure of the protein (polypeptide). The altered amino acid sequence would then form a different secondary structure due to the hydrogen bonds forming between the different amino acids. An altered secondary structure results in a different tertiary structure, as different parts of the sequence would interact in different ways, creating ionic or disuphide bonds, or hydrophobic/philic regions in different places to the position in which they would reside in the protein coded from the original DNA sequence.

WS

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