Applications of biotechnology

MDCAT Biology · Biology · Biotechnology. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.

Test this topic free All MDCAT Biology topics

The idea

Once a gene can be moved from one organism to another, it can be put to use. An organism that carries a gene from another species is called transgenic. In medicine, bacteria or yeast with human genes make human proteins such as insulin, growth hormone and vaccine antigens. Gene therapy goes further and puts a normal allele into a patient's own cells.

In agriculture, crops are given genes for pest resistance, herbicide resistance or better nutrition.

DNA fingerprinting identifies people from their DNA, and cloning makes genetically identical copies of an organism. These methods raise questions of safety, fairness and privacy that science alone cannot settle.

Rules to remember

Human insulin from recombinant bacteria treats diabetes mellitus; recombinant growth hormone treats pituitary dwarfism
Hepatitis B vaccine is a viral surface protein made in yeast; it has no whole virus, so it cannot cause the disease
Gene therapy of body (somatic) cells is not inherited, because the eggs and sperm still carry the faulty allele
Bt crops carry a gene from Bacillus thuringiensis for a protein that kills insect larvae; golden rice makes beta-carotene, which the body turns into vitamin A
DNA fingerprinting compares repeated non-coding sequences (VNTRs or STRs); only identical twins share a profile, and every band in a child comes from the mother or the father
Reproductive cloning by nuclear transfer (Dolly, 1996): the clone is genetically identical to the animal that gave the nucleus
Ethical issues include gene flow to wild plants, long-term safety of GM food, privacy of genetic data and the cloning of humans

Common mistake

A clone made by nuclear transfer is not a copy of the egg donor or of the surrogate mother. Its nuclear DNA comes only from the animal whose body cell supplied the nucleus.

Worked example

Before genetic engineering, people with diabetes were treated with insulin taken from the pancreas of cattle and pigs. Why is insulin made by recombinant bacteria better?

The bacteria carry the human insulin gene, so they make a protein identical to human insulin.
Animal insulin differs slightly in its amino acids, so it can cause an immune or allergic reaction in some patients.
Bacteria multiply quickly in fermenters, so large and reliable amounts can be made at low cost, with no need for animal tissue.

Answer: Recombinant insulin is identical to human insulin, so it is less likely to cause an immune reaction, and it can be produced in large amounts.

Ask about this

Type what you are stuck on. The helper finds the explanation, worked examples and the notes to read, free and instant.

Keep going

← Recombinant DNA techniques Take a MDCAT Biology test