Biotechnology and Genetic Engineering


Biotechnology involves using living organisms to carry out processes that make substances that we eat.

For example,

  • Yeast has been used to make bread and alcohol.
  • Lactobacillus bacteria have been used to make yoghurt and cheese
  • Microorganisms can also be used to extract some enzymes
  • Genetic engineering also uses microorganisms for obtaining substances such as insulin

Why microorganisms?

No ethical issues in using them

  • Share the same genetic code of DNA
  • Also have little loops of DNA called plasmids that can be used in moving genes from one organism’s cells into other
  • Microscopic structure- easy to store
  • Easy to grow in laboratory
  • Take up less space
  • Able to produce wide range of substances
  • Their reproduction rate is high


  • Yeast is a unicellular fungus.
  • It is able to respire anaerobically, and it produces ethanol and carbon dioxide as it does so.

Uses of yeast

  • Bread making
  • Making bio-fuels
  • Making alcohol (brewing)

Bread making

Wheat flour contains lot of starch and a protein called gluten.

To make bread:

  1. Flour is mixed in water
  2. Yeast is added
  3. A dough is prepared
  4. In the dough, amylase (enzyme) breaks down starch in the dough to maltose and some glucose.
  5. These products are used by the yeast in anaerobic respiration.
  6. Yeast produces bubbles of carbon dioxide, that get trapped in the dough
  7. Gluten in the flour makes the bread stretchy.
  8. Carbon dioxide bubbles help the dough to rise.
  9. The dough is baked
  10. Baking removes the alcohol and kills the yeast.


Bio-fuels are made by yeast and it produces ethanol. They are crucial in order to replace non-renewable energy sources such as petroleum.

Making bio-fuels:

  1. Maize is treated with amylase
  2. Addition of amylase breaks down stored starch to glucose.
  3. A solution of sugars made by plants is extracted.
  4. Yeast is added to the solution.
  5. The solution is enclosed in a container with vacuum to support anaerobic respiration in the yeast.
  6. An air lock is added so that bacteria cannot enter the solution.
  7. At the end of fermentation, ethanol is produced
  8. The ethanol is then purified using distillation.
Advantages Disadvantages
Alcohol burns well Doesn’t contain as much energy per litre, as fossil fuels do
It is a sustainable source Crops take up land

may harm natural habitats

Helps to reduce amount of carbon dioxide in the atmosphere Growing enormous amounts of such crops increases its price

makes it unaffordable for  people to buy food

Making use of enzymes

Enzyme production is one of the most prominent uses of Genetic Engineering (to know more about enzymes click here)


Lactase is an enzyme that breaks down lactose, a sugar found in milk, to glucose and galactose.

Lactose à glucose + galactose

Milk is treated with lactose, so that people of Asian descent can readily digest it and not feel ill.

Reasons of using lactase:

  • Babies start secreting lactase in the early months of their life to break down the lactose in the milk to simple molecules.
  • Some people of the Asian descent stop making lactose when they grow older.
  • Hence for such people, it is tough to digest milk products. They often feel unwell when they eat food such as cheese or butter.
  • Moreover, glucose and galactose is used commercially to make sweets.


Penicillium - Genetic Engineering and Biotechnology

Genetic engineering

Changing the genetic material of an organism by

  • Removing
  • Changing
  • Inserting

…Individual genes is called as genetic engineering.

Where genetic engineering has been used:

  • In the production of insulin (for people with type 1 diabetes)
  • For crop plants to get resistant towards herbicides and insect pests.
  • For rice to produce more vitamin A (so that people with severe vitamin A deficiency can be cured)

The process for genetic engineering

Production of human insulin using bacteria is an important component of biotechnology.

  1. Some human cells are liquidized
  2. The DNA is made to precipitate by addition of chemicals
  3. Restriction enzymes are added to cut the DNA into pieces with specific length.
  4. Human DNA with sticky ends are formed
  5. Simultaneously, restriction enzyme is used again to cut the plasmid(s) DNA
  6. Again DNA with sticky ends forms.
  7. Both the sticky ends are complementary (similar) to each other.
  8. Using ligase enzyme, the human gene for insulin and the plasmid DNA are joined
  9. The plasmid acts as a vector putting the human insulin gene into a bacterium
  10. This forms a genetically engineered bacteria
  11. The genetically engineered bacteria are grown in a fermenter
  12. They reproduce asexually and make human insulin
  13. The insulin is filtered and purified and used.

External Links

  1. Genetic Engineering

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