The big picture
One spoon of curd. Seven ideas about the crowd inside it.
| Idea | Remember | Example |
|---|---|---|
| A world below the eye | Size seen = real size × power. The eye sees about 0.1 mm. | 0.005 mm × 100 = 0.5 mm |
| Four kinds | Bacteria, fungi and protozoa are cells. A virus is not. | Yeast is a fungus |
| Where they live | Water, soil, air, food and living things. | A drop of pond water |
| The useful ones | Yeast, bacteria and fungi do jobs for us. | Dough, curd, compost |
| When food spoils | Warm and damp help them. Cold slows them. | Cut mango on a shelf |
| Helps or harms | Many help us. Some harm us or our food. | Damp grain goes mouldy |
| Keeping them from growing | A lot of salt or sugar stops them. | Mango pickle |
Open your NCERT book. Chapter 2 is The Invisible Living World: Beyond Our Naked Eye. Curd, dough, compost and pickle all show what microbes do.