Chapter 3: MICRO-ORGANISMS



  Introduction

Micro –organisms are of four types: bacteria [TB, typhoid, cholera, diphtheria, and plague], algae, protozoa [dysentery, malaria] and fungi. Virus [jaundice] reproduces only inside host organisms.


Lactobacillus multiplies in milk and turns it into curds.




Amoeba is a single celled organism. It has pseudopodia which are finger like projections. These capture the food particle and put it in the food vacuole. After digestion the leftover matter is expelled by the vacuole. Amoeba reproduces asexually by binary fission.


Hen egg is also single cell.


Bacteria living in our mouth break food and leave acid that causes tooth decay. Tooth decay is caused when the pH of mouth goes below 5.5. Calcium phosphate, insoluble in water and is the hardest substance in the body but at pH 5.5 it starts dissolving.


Female Anopheles mosquito carries malaria parasite and female aedes mosquito carries dengue virus.




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