Q.Mention the chemical change that proinsulin undergoes, to be able to act as mature insulin.
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Recombinant Protein Therapeutics
Imagine you need a specific medicine—say, insulin for diabetes—but the only way to get it used to be from the pancreas of cows or pigs. That was expensive, risky (animal proteins could trigger allergies), and never quite identical to human insulin. Now, we can take the human gene that makes insulin, put it into a harmless bacterium or yeast, and let that microbe churn out perfect human insulin in huge vats. That is the core idea of recombinant protein therapeutics.
Recombinant means "made by combining DNA from different sources." Protein therapeutics means "a protein used as a medicine." So, recombinant protein therapeutics are medicines that are proteins, made by genetically engineered living cells, to treat or prevent disease.
The NCERT textbook (Class 12 Biology, Chapter 12, Biotechnology and its Applications) introduces this under "Biotechnological Applications in Medicine." It specifically mentions human insulin (Humulin) as the first recombinant therapeutic approved for human use. The textbook explains that the human insulin gene was inserted into E. coli bacteria, which then produced insulin identical to our own.
How does it work, step by step?
- Identify the gene that codes for the therapeutic protein (e.g., the gene for human insulin, growth hormone, or clotting factor).
- Insert that gene into a "vector" (a carrier DNA, often a plasmid from a bacterium) using restriction enzymes and DNA ligase.
- Introduce the vector into a host cell (usually E. coli bacteria, yeast, or mammalian cells). This host cell is now "transformed" – it carries the human gene.
- Grow the host cells in large fermenters. As they multiply, they follow the human gene's instructions and produce the human protein.
- Purify the protein from the culture. The final product is a pure, human-identical therapeutic protein, free from animal contaminants.
Why does this matter? (The "why" for a commerce/humanities student)
- Safety and Efficacy: Because the protein is exactly human, the body rarely rejects it. No risk of animal viruses or allergic reactions to animal proteins.
- Scalability: You can produce massive quantities in a lab, independent of animal supply. One batch of engineered bacteria can make more insulin in a day than thousands of pig pancreases.
- Cost (eventually): While initial R&D is expensive, mass production drives down cost, making life-saving drugs accessible to more people.
- New Treatments: It enables therapies that were impossible before—like monoclonal antibodies for cancer, or erythropoietin for anaemia in kidney patients.
The NCERT textbook emphasises that recombinant therapeutics are "relatively free from risk of infection and immune response" compared to products extracted from animals or human cadavers. This is the single biggest advantage: purity and human compatibility.
Examples you should know (from NCERT and common knowledge) …
Insulin is first made as a longer precursor, pro-insulin, which must be processed before it becomes functional — a key example in the NCERT Class 12 Biology chapter on biotechnology and its applications (genetically engineered insulin). …
Pro-insulin becomes mature insulin by the removal of the C-peptide (the connecting peptide), leaving the A and B chains linked by disulphide bonds.
Concept. Insulin is a peptide hormone made of two short polypeptide chains, A and B, held together by disulphide bridges. In humans (and mammals) it is synthesised first as a pro-hormone (pro-insulin) that needs processing to become fully mature and functional.
Why the change is needed. Pro-insulin contains an extra polypeptide stretch — the C-peptide — in addition to the A and B chains. This extra peptide is not present in the mature, functional hormone.
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Showing the 12 most recent of 14 on this concept.
- GUJCET 2026Set 051 markMCQQ.At present, about _______ recombinant therapeutics have been approved for human-use, the world over. (A) 10 (B) 25 (C) 15 (D) 30
›Reveal solutionSolution
Roughly 30 recombinant therapeutics are approved for human use.
As stated in the textbook, at present about 30 recombinant therapeutics have been approved for human use the world ove …
- GSEB Higher Secondary Certificate (HSC) Examination 2026Set ANNUAL1 markMCQQ.At present, how many recombinant therapeutics have been approved for human - use the world over.(a) 30(b) 12(c) 20(d) 24
›Reveal solutionSolution
Biotechnology-derived (recombinant) therapeutics such as insulin, growth hormone and several vaccines number about 30 approved products globally.
Genetic engineering has enabled the production of numerous therapeutic proteins (e.g. recombinant human insulin, human growth hormone, various vaccines and clotting factors) in microbial or cell-culture systems, avoiding the impurities and immune reactions associat …
- GSEB Higher Secondary Certificate (HSC) Examination 2026Set ANNUAL1 markMCQQ.From the transgenic animal, which human protein is used for the treatment of emphysema?(a) alpha - lactalbumin(b) Thyroxin(c) alpha - 1 - antitrypsin(d) Insulin
›Reveal solutionSolution
Transgenic animals (e.g. sheep) have been engineered to produce human alpha-1-antitrypsin in their milk, a protein used to treat emphysema.
Emphysema is a lung disease that can be treated with the human protein alpha-1-antitrypsin. Transgenic technology has been used to produce this protein in the milk of transgenic animals (such as sheep), providing a source for treating patients with emphysema and related conditions. Alpha-lactalbumin, thy …
- GSEB Higher Secondary Certificate (HSC) Examination 2025Set ANNUAL1 markMCQQ.The polypeptide chain-A and chain-B of insulin are joined to each other by which bond?(a) Glycosidic(b) Disulfide(c) Dipeptide(d) Diester
›Reveal solutionSolution
Mature insulin consists of two polypeptide chains (A and B) held together by disulfide (–S–S–) bonds.
Insulin is synthesised as a single precursor, proinsulin, which contains a connecting (C) peptide. During maturation this C peptide is enzymatically excised, leaving two separate polypeptide chains, chain A (21 amino acids) and chain B (30 amino acids), which remain linked to each other by disulfide bonds formed between cysteine residues on the two chains. This is also why recombinant hum …
- GSEB Higher Secondary Certificate (HSC) Examination 2025Set ANNUAL1 markMCQQ.Which human protein is used for the treatment of emphysema?(a) α-1 antitrypsin(b) α-1 erepsin(c) α-1 trypsin(d) α-1 enterogastrin
›Reveal solutionSolution
Alpha-1 antitrypsin, produced via genetic engineering (e.g. in transgenic animals/microbes), is used to treat emphysema.
Emphysema is a lung disease that can result from a genetic deficiency of the protein alpha-1 antitrypsin, which normally protects lung tissue from damage by the enzyme elastase. Recombinant alpha-1 antitrypsin (produced, for example, in the milk of transgenic animals such as sheep, …
- GSEB Higher Secondary Certificate (HSC) Examination 2024Set ANNUAL1 markMCQQ.In mature insulin, chain A and chain B interlinked by which bond?(a) Peptide bond(b) Hydrogen bond(c) Glycosidic bond(d) Disulphide bond
›Reveal solutionSolution
Mature (functional) insulin is a two-chain protein, A chain and B chain, covalently joined only by disulphide (-S-S-) bonds between cysteine residues.
Insulin is first synthesised as a single-chain precursor, pro-insulin, which contains an extra connecting C-peptide between what will become the A and B chains. During maturation this C-peptide is enzymatically removed, leaving the A and B chains as two separate polypeptides — but they do not fall apart, because cysteine residues on each chain form covalent disulphide bridges that link A to B (this is exactly why recombinant human insulin, produced by inserting the A and B chain genes separately into E. coli, has to be c …
- GSEB Higher Secondary Certificate (HSC) Examination 2024Set ANNUAL1 markMCQQ.In which disease alpha-1 antitrypsin is used to treat?(a) Asthama(b) Common cold(c) Pneumonia(d) Emphysema
›Reveal solutionSolution
Alpha-1 antitrypsin, produced using transgenic technology (famously in the milk of transgenic sheep), is used to treat emphysema, a lung disease caused by deficiency of this protective protein.
Emphysema results when the lungs' elastic tissue is progressively destroyed by an enzyme (elastase) that is normally kept in check by alpha-1 antitrypsin; when a person is genetically deficient in this protein, lung damage accumulates. Producing recombinant alpha-1 antitrypsin (e.g. via transgenic animals whose milk is engineer …
- GSEB Higher Secondary Certificate (HSC) Examination 2023Set ANNUAL1 markMCQQ.The first human hormone produced by recombinant DNA technology is ________(a) Progesterone(b) Insulin(c) Thyroxin(d) Estrogen
›Reveal solutionSolution
Insulin (Humulin) was the first human hormone produced by recombinant DNA technology.
In 1983 the company Eli Lilly used recombinant DNA technology to make human insulin: the two chains A and B were produced separately in E. coli and then joined by disulfide bonds. This 'Humulin' wa …
- GSEB Higher Secondary Certificate (HSC) Examination 2022Set ANNUAL1 markMCQQ.In the formation of insulin, the 'A' and 'B' polypeptide chains are joined to each other by which bond?(a) Glycosidic bond(b) Peptide bond(c) Phosphodiester bond(d) Disulfide bond
›Reveal solutionSolution
Mature insulin consists of two separate polypeptide chains, A and B, that are linked together by disulfide bonds.
Insulin is initially synthesised as a single precursor polypeptide (proinsulin) containing a connecting C-peptide between what will become the A and B chains. During processing, the C-peptide is excised, and the resulting A chain and B chain remain joined together only by disulfide (S-S) bonds — not by peptide bonds (which link amino acids within a single chain), glycosidic bonds (which link sugar units), or phosphodiester bonds (whic …
- GSEB Higher Secondary Certificate (HSC) Examination 2022Set ANNUAL1 markMCQQ.The human protein Alpha-1 antitrypsin is used in the diagnosis of which disease?(a) Emphysema(b) Phenylketonuria(c) Cystic fibrosis(d) All of the above
›Reveal solutionSolution
The human protein Alpha-1-antitrypsin, produced using biotechnology, is used in relation to emphysema, a chronic lung disease.
Alpha-1-antitrypsin is a protease inhibitor normally produced by the liver; its deficiency allows destructive enzymes to damage lung tissue, leading to emphysema. Biotechnologically produced Alpha-1-antitrypsin (e.g., from transgenic sources) is used to treat/diagnose this deficiency-related condition, …
- GUJCET 2021Set 151 markMCQQ.Human protein α-1-antitrypsin is used to treat which disease? (A) lukemia (B) emphysema (C) cancer (D) AIDS
›Reveal solutionSolution
Recombinant human alpha-1-antitrypsin treats emphysema.
Concept. α-1-antitrypsin deficiency causes emphysema; the human protein is administered to treat it. …
- GSEB Higher Secondary Certificate (HSC) Examination 2020Set ANNUAL1 markMCQQ.Insulin chain A and Chain B are linked together by ________.(a) Disulfide bond(b) Peptide bond(c) Sulphur bond(d) Hydrogen bond
›Reveal solutionSolution
Mature human insulin is composed of two polypeptide chains, A and B, held together by disulfide bonds (bonds between two sulfur-containing cysteine residues).
Insulin, when finally processed and secreted by the pancreas, consists of two separate polypeptide chains — chain A and chain B — that are connected to each other by disulfide (–S–S–) bridges formed between cysteine residues on the two chains (with an additional intra-chain disulfide bond within chain A). In the recombinant production of human insulin by genetic engineering, the A and B chains are produced separately (e.g …
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