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4.10 process information to construct a flow chart that shows that changes in DNA sequences can result in changes in cell activity
process information to construct a flow chart that shows that changes in DNA sequences can result in changes in cell activity
- If there is a simple substitution for a single base pair on a strand of DNA such as a G-C replaced by A-T, then this will result in a different amino acid codon forming a different polypeptide. If one base pair is lost from the sequence there will be a shift along the DNA molecule producing different polypeptides.The flow chart below shows the reaction if thymine is lost from the start of a DNA sequence.

- Cell activity is controlled by enzymes. Enzymes are formed from chains of polypeptides. If the chain of amino acids forming the polypeptide is not in the right sequence, then the enzyme formed will not be functional. In this case, there is a premature stop.
For another example, go to the following webpage.
What does DNA code for?
genome.org, Wellcome Trust Sanger Institute.