Biotechnology Applications

Q1. (2 marks)

• (a) A transgenic organism is an organism whose genome has been altered by the introduction of one or more genes from another species/source. (1)
• (b) A GMO (genetically modified organism) is any organism whose genetic material has been altered using genetic engineering/recombinant DNA technology. (1) Why: transgenic is a subset of GMO (foreign gene added); GMO is the broader term.

Q2. (6 marks)

• (a) Escherichia coli (E. coli). (1)
• (b) The A chain and B chain, joined by disulphide (—S—S—) bonds. (1 + 1)
• (c) The DNA sequences for the A and B chains were synthesised/inserted separately into plasmid vectors; the vectors were introduced into E. coli; bacteria expressed the two chains; the chains were extracted and combined/joined by disulphide bonds to form functional insulin. (3: 1 for cloning genes into vector/bacteria, 1 for expression, 1 for combining chains)

Q3. (6 marks)

• (a) Bacillus thuringiensis; encodes a Cry protein / Bt toxin (insecticidal crystal protein). (1 + 1)
• (b) The Bt protein is produced as an inactive protoxin that is only activated (cleaved) in the alkaline gut of insects, where it binds specific gut receptors; humans have an acidic stomach and lack these receptors, so it is broken down harmlessly. (2)
• (c) A crop genetically engineered to tolerate a specific herbicide so the herbicide kills weeds but not the crop. (1) Advantage: allows effective weed control / less tillage / higher yield (any one). (1)

Q4. (3 marks)

• (a) Biofortification = increasing the nutritional (vitamin/mineral) content of crops through breeding or genetic engineering. (1)
• (b) Produces beta-carotene (provitamin A) in the endosperm; aims to reduce Vitamin A deficiency (which causes blindness). (1 + 1)

Q5. (4 marks) Any two valid differences, 2 marks each:

• mRNA vaccine delivers mRNA coding for antigen → host cells make the antigen; subunit vaccine delivers the ready-made recombinant protein antigen. (2)
• mRNA vaccines are faster to design/manufacture and need cold-chain storage; recombinant protein vaccines are produced in cell cultures and are generally more thermostable. (2) (Other valid contrasts accepted.)

Q6. (5 marks)

• (a) B lymphocyte (antibody-producing plasma B cell) and myeloma (cancer/tumour) cell. (1 + 1)
• (b) B cell provides the specific antibody-producing ability; myeloma cell provides immortality / unlimited division in culture. (1 + 1)
• (c) Any one: cancer therapy / diagnostic tests (pregnancy test) / treating autoimmune disease. (1)

Q7. (3 marks)

• (a) Reproductive cloning produces a whole new organism genetically identical to the donor; therapeutic cloning produces embryonic stem cells/tissues for treatment (no whole organism produced). (1 + 1)
• (b) Dolly the sheep. (1)

Q8. (3 marks)

• (a) iPSCs are adult/somatic (differentiated) cells reprogrammed back to a pluripotent state by introducing specific transcription factors. (2)
• (b) Avoids ethical issues of using embryos / can be patient-specific (reduces rejection). (1)

Q9. (3 marks)

• (a) Any two: temperature, pH, oxygen/aeration, agitation, nutrient supply. (1 + 1)
• (b) Any one: antibiotics (penicillin), ethanol, insulin, enzymes, citric acid, vitamins. (1)

Q10. (5 marks)

• (a) Bioremediation = use of living organisms (microbes/plants) to remove or detoxify pollutants from the environment. (1)
• (b) e.g. Bioethanol produced by yeast (Saccharomyces) fermentation of sugars; or biogas by anaerobic bacteria. (1 + 1)
• (c) Synthetic biology aims to design and construct new biological parts/pathways or redesign existing ones for useful purposes. (2)

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  {"claim":"Paper has 10 questions","code":"result=(len([2,6,6,3,4,5,3,3,3,5])==10)"},
  {"claim":"Q6 marks breakdown (2+2+1) equals 5","code":"result=(2+2+1==5)"},
  {"claim":"Q2 marks breakdown (1+2+3) equals 6","code":"result=(1+2+3==6)"}
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