Engineering Life: Miracles in Biotechnology (Advanced)

Using living things to make useful products: traditional and modern biotechnology, making insulin in bacteria, Bt crops, bio-enzymes, fermenters and how microbes grow.

Key ideas

• Traditional biotechnology uses natural microbes (curd, bread, idli, kanji); modern biotechnology moves genes between organisms.
• Microbes are ideal tools: they grow fast in little space on simple food, and their DNA is easy to change.
• Insulin: cut the gene and a plasmid with the same restriction enzymes, join them with DNA ligase, put the plasmid in E. coli, grow, purify.
• Bt crops carry a toxin gene from Bacillus thuringiensis and kill the pests that feed on them; Golden Rice makes beta-carotene.
• Blue biotechnology uses marine and freshwater organisms, green serves farming and food, red serves medicine.
• A fermenter is sterilised first, then stirred, aerated, cooled and kept at the right pH.
• Microbes pass through lag, log, stationary and decline phases; a continuous culture keeps them in the log phase.

Remember

Watch out

• Adding the starting number at each doubling instead of multiplying by 2.
• Calling the fastest growth the stationary phase: it is the log phase.
• Calling curd-making modern biotechnology: no genes are moved.

Worked example