Microorganisms: Friends and Foe Chapter 1

Microorganisms: Friends and Foe

• Microorganisms are living organisms that cannot be seen with the naked eye and are present all around us.
• Examples of microorganisms include the greyish white patches that grow on moist bread and the tiny organisms found in water and soil.

Observation of Microorganisms

• Using a magnifying glass, you can observe tiny, black, rounded structures on the surface of moist bread.
• Under a microscope, you can see microorganisms in water and soil, such as tiny organisms moving around in a drop of pond water.

Classification of Microorganisms

• Microorganisms can be classified into four major groups: bacteria, fungi, protozoa, and some algae.
• Examples of microorganisms are shown in Figs. 1.1-1.4.

Viruses

• Viruses are microscopic and can only reproduce inside the cells of a host organism, which can be a bacterium, plant, or animal.
• Viruses cause common ailments like cold, influenza, and most coughs, as well as serious diseases like polio and chicken pox.
• Examples of viruses are shown in Fig. 1.5.

Diseases Caused by Microorganisms

• Protozoans cause diseases like dysentery and malaria.
• Bacterial diseases include typhoid and tuberculosis (TB).

Microorganisms: Habitat and Structure

• Microorganisms can survive in various environments, including extreme temperatures (ice cold to hot springs), deserts, marshy lands, and inside animal bodies.
• Single-celled microorganisms include bacteria, algae, and protozoa.
• Multicellular microorganisms include algae and fungi.

Microorganisms: Role in Human Life

• Microorganisms play a crucial role in human life, with both beneficial and harmful effects.
• Beneficial microorganisms are used in various industries, such as food, medicine, and environment.
• Harmful microorganisms can cause diseases in humans.

Beneficial Microorganisms

• Microorganisms are used in food production, such as:
  • Curd preparation (Lactobacillus promotes curd formation)
  • Bread making (yeast reproduces rapidly, producing carbon dioxide)
  • Cheese, pickles, and other food items
• Microorganisms are used in:
  • Medicinal production
  • Environmental cleanup
  • Increasing soil fertility by fixing nitrogen

Microorganisms in Food Production

• Lactobacillus is a bacterium involved in curd formation.
• Yeast is used in bread making, producing carbon dioxide and causing dough to rise.
• Yeast is also used in the baking industry for making pastries, cakes, and other products.