3.35B understand how a change in DNA can affect the phenotype by altering the sequence of amino acids in a protein

- Mutations involving a change in DNA sequence can affect the structure and function of proteins. This causes an alteration to the base pair sequence in the genetic code.

- Remember that for protein synthesis to occur, DNA sequence needs to be transcribed and translated.
Each gene acts as a code for a specific protein, and each triplet of bases (codon) codes for one particular amino acid. The amino acid molecules join together to form a protein molecule.

- When mutations change the base sequence of DNA, this will change the base sequence of the complementary mRNA transcript during transcription.



- Modified mRNA transcript will be translated to code for different amino acids, changing the structure of the polypeptide chain (amino acid chain). So if there is a change in bases due to a mutation, there can be a change in amino acid sequence resulting in a change in protein structure and function.