Worksheets › Class 9 › Engineering Life: Miracles in Biotechnology (Advanced) › Cheat sheet
Class 9 Engineering Life: Miracles in Biotechnology (Advanced): cheat sheet
CBSE Science. 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
| Doubling | number = start × 2ᵏ, where k = time ÷ doubling time |
| Growth rate | change in number ÷ time taken |
| Fermenter parts | impeller mixes; sparger adds air; cooling jacket removes heat; pH sensor triggers adding a base |
| Bio-enzymes | protease → protein; amylase → starch; lipase → fats and oils |
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
A continuous-culture fermenter holds 8,000 litres. Fresh medium flows in at 310 litres per hour and the same volume of spent broth is removed. (a) How many litres are removed in a day? (b) How many hours does it take to replace a volume equal to the whole tank? (c) In which growth phase does this keep the microbes? (Give the answer to 2 decimal places where needed.)
Working: (a) 310 × 24; (b) 8,000 ÷ 310; (c) fresh food in and waste out keep them growing fast
Answer: (a) 7,440 litres; (b) 25.81 hours; (c) log phase
Practise Engineering Life: Miracles in Biotechnology (Advanced)
Revise with this page, then practise: every Engineering Life: Miracles in Biotechnology (Advanced) sheet in the app is new, with an answer key and working.
Coming soon for Android and iPhone.