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4.9 analyse information from secondary sources to outline the evidence that led to Beadle and Tatum’s ‘one gene – one protein’ hypothesis and to explain why this was altered to the ‘one gene – one polypeptide’ hypothesis

analyse information from secondary sources to outline the evidence that led to Beadle and Tatum’s ‘one gene – one protein’ hypothesis and to explain why this was altered to the ‘one gene – one polypeptide’ hypothesis

 

Sample

Beadle and Tatum used bread mould to investigate nutritional mutations. Using X-rays, they produced mould that was unable to produce a specific amino acid.  The mould was unable to grow unless the amino acid was added. They showed that genes controlled biochemical processes. Their hypothesis was that for each gene there was one enzyme or protein. The enzymes that they studied consisted of one polypeptide but many enzymes consist of chains of polypeptides. Therefore, the hypothesis has been changed to the “one – gene one – polypeptide” hypothesis.