3D tissue and organ printingIB MYP Biology: Subtopic test

1. 1
   A hospital research laboratory in Singapore uses a bioprinter to make small pieces of human skin. A computer controls a nozzle that deposits a gel containing living human skin cells and nutrients, one thin layer at a time, to build up the tissue. The printed skin is then placed in a warm incubator.

   (a)

   What is the gel, containing living cells and nutrients, that is used in the printer called?

   [1 mark]

   • ABioink
   • BPlastic resin
   • CAntibiotic
   • DAntiseptic

   (b)

   What term is used for a group of similar cells that work together to do a job?

   [1 mark]

   • AOrgan
   • BTissue
   • COrganism
   • DOrgan system

   (c)

   Explain why the printed skin must be kept in a warm incubator with nutrients after printing.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   In many countries, patients with kidney failure wait years for a donor kidney. A donated organ must match the patient's tissue type, otherwise the patient's immune system may attack it and reject it, so patients take drugs that weaken their immune system for the rest of their lives. Researchers hope one day to print a replacement kidney using cells taken from the patient.

   (a)

   Why would a kidney printed from the patient's own cells be less likely to be rejected?

   [1 mark]

   • AIt would be made from plastic
   • BThe patient would not need any surgery
   • CIts cells carry the patient's own antigens, so the immune system does not see them as foreign
   • DIt would be made in a sterile laboratory

   (b)

   Which of these is a current limit of printing whole organs?

   [1 mark]

   • APrinters cannot print living cells
   • BHuman cells cannot divide
   • CNo computer can control a printer
   • DIt is difficult to build the network of blood vessels that supplies every cell

   (c)

   Describe two advantages of a printed kidney made from the patient's own cells compared with a donor kidney.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A pharmaceutical company wants to test a new drug for its effect on the liver. Scientists print human liver tissue and place 20 samples of it in each of four solutions containing 0, 10, 50 and 100 micromolar concentrations of the drug for 48 hours. They then count the percentage of cells that are still alive. The mean percentages of living cells were 98%, 95%, 71% and 32% respectively.

   (a)

   Explain why the scientists included samples with 0 micromolar of the drug and used 20 samples at each concentration.

   [3 marks]

   (b)

   Describe the trend in the results and evaluate the use of printed human liver tissue, instead of rats, to test the drug.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A hospital in Mexico City treats many patients with severe burns and others who are waiting for organ transplants. Bioprinted skin has already been used in small trials on burns, and printed cartilage has been tested, but no printed organ such as a kidney has yet been transplanted into a person. A bioprinter costs hundreds of thousands of dollars. Some doctors say the hospital's money would be better spent on campaigns to increase organ donation.

   (a)

   Discuss the benefits and drawbacks of bioprinting skin and organs for patients, and give a justified conclusion.

   [6 marks]

   (b)

   Evaluate the argument that the hospital should spend its money on organ donation campaigns instead of bioprinting.

   [6 marks]

   Total for question 4: 12 marks

End of questions