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Diabetes can be an autoimmune condition where the body is activated to destroy the beta cells in the pancreas that produce insulin - VCE - SSCE Biology - Question 6 - 2023 - Paper 1
Question 6
Diabetes can be an autoimmune condition where the body is activated to destroy the beta cells in the pancreas that produce insulin. Human insulin is a peptide hormon... show full transcript
Worked Solution & Example Answer:Diabetes can be an autoimmune condition where the body is activated to destroy the beta cells in the pancreas that produce insulin - VCE - SSCE Biology - Question 6 - 2023 - Paper 1
Step 1
Outline how human insulin is made using recombinant plasmids.
Answer
Human insulin is produced through the following steps:
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Isolation of Insulin Genes: The genes coding for chains A and B of human insulin are isolated using restriction endonucleases, which cut DNA at specific sequences.
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Insertion into Plasmid: Each insulin gene is inserted into separate plasmids. These plasmids are circular DNA molecules that are engineered to carry foreign DNA into host cells.
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Transformation of Bacteria: The recombinant plasmids are introduced into bacteria (usually E. coli), which undergo transformation. This allows the bacteria to uptake the insulin genes.
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Selection and Screening: Antibiotic selection is often used to ensure that only the bacteria containing the recombinant plasmids survive, while others are eliminated.
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Expression of Insulin: The transformed bacteria are cultured to produce insulin chains. The bacteria express the insulin genes, resulting in the production of polypeptide chains A and B.
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Protein Processing: Finally, the two chains are harvested and treated to form functional insulin via disulfide bond formation between them.
Step 2
Identify which type of insulin is rapid acting compared to regular insulin. Use data from the graph to justify your response.
Answer
The rapid-acting insulin is lispro. According to the data from the graph, lispro peaks quickly at around 2 hours, reaching approximately 7 arbitrary units, compared to regular insulin which peaks later at about 5 units after roughly 7 hours. This indicates that lispro acts more rapidly than regular insulin, with its duration of action being shorter at around 2 hours.
Step 3
Step 4
What should scientists consider when altering the primary structure of insulin? Justify your response.
Answer
Scientists should consider the tertiary structure of insulin when altering its primary structure. Changes in the amino acid sequence can affect how the protein folds and its overall functionality. If the tertiary structure is disrupted, it may lead to a loss of biological activity. Therefore, modifications should ensure that the functional conformation is preserved, maintaining insulin's efficacy in regulating blood glucose levels.