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The path to human insulin In the 1970s, recombinant deoxyribonucleic acid methods for cloning and expressing genes in the bacteria *Escherichia coli* were under intense development - VCE - SSCE Biology - Question 10 - 2021 - Paper 1
Question 10
The path to human insulin In the 1970s, recombinant deoxyribonucleic acid methods for cloning and expressing genes in the bacteria *Escherichia coli* were under int... show full transcript
Worked Solution & Example Answer:The path to human insulin In the 1970s, recombinant deoxyribonucleic acid methods for cloning and expressing genes in the bacteria *Escherichia coli* were under intense development - VCE - SSCE Biology - Question 10 - 2021 - Paper 1
Step 1
What is meant by recombinant deoxyribonucleic acid in the context of this article?
Answer
Recombinant deoxyribonucleic acid (DNA) refers to DNA molecules that have been artificially created by combining genetic material from different sources. In this context, it involves taking the human insulin gene and integrating it into a plasmid, which can then be introduced into bacteria such as E. coli for expression and production of human insulin.
Step 2
The article states that the researchers knew the structure of insulin and the amino acid sequence before they created recombinant human insulin in the laboratory. How might the researchers have used this information to genetically engineer a human insulin gene from human DNA?
Answer
The researchers could work backwards from the known amino acid sequence of insulin to determine the corresponding mRNA or DNA sequence. This is because the sequence of amino acids in a protein is dictated by the nucleotide sequence in the DNA. They would account for potential redundancy in the genetic code and the possibility of introns being present in the natural gene.
Step 3
Outline the steps that show how researchers clone and express the gene in bacteria.
Answer
- Isolate the human insulin gene: Extract human insulin gene from human DNA or artificially synthesise the insulin gene based on the known sequence.
- Insert the gene into a plasmid: Utilize restriction enzymes to cut the plasmid and ligases to join the human insulin gene to form a recombinant plasmid.
- Transform into bacteria: Introduce the recombinant plasmid into E. coli bacteria, which are then cultured to propagate the insulin gene and produce insulin.