Track quiz
Before the questions, here are the seven rules this track worked with.
| Idea | The rule, as the lab applies it |
|---|---|
| A world below the eye | A microscope lens makes a thing look bigger. Size seen = real size × power. An eye can see about 0.1 mm or more. Anything smaller needs a lens. |
| Four kinds | Bacteria and protozoa are single cells. A fungus is one cell (yeast) or many threads (mould). A virus is not a cell. It multiplies only inside a host. |
| Where they live | Microbes live in water, soil, air, food and inside living things. Some live in hot springs and in snow. |
| The useful ones | Yeast needs sugar, water and warmth. Then it makes carbon dioxide gas. The gas fills a balloon. It turns lime water milky. |
| When food spoils | Microbes grow on food. Warmth and moisture make them grow faster. Cold makes them grow slower. It does not kill most of them. |
| Helps or harms | Many microbes help us. Some harm us or our food. Judge a microbe by what it does for us where it is. |
| Keeping them from growing | A lot of salt or sugar stops most microbes growing. A little does not. |
A microbe is 0.005 mm across. How big does it look through a ×100 lens?
A microbe looks 0.05 mm through a ×10 lens. Can an eye see it?
A clue card says: not a cell, multiplies only inside a host. Which kind is it?
Yeast makes dough rise. Which kind of microbe is yeast?
A drop of pond water shows Amoeba. Which kind is it?
Warm sugar solution with no yeast has a balloon on top. What happens?
Curd sets in a warm bowl of milk, not a cold one. Why?
Two cut mango slices: one on a shelf, one in a fridge. Which gets mould first?
A farmer grows beans and adds no nitrogen fertiliser. Why can she?
Which helps keep microbes from growing in a jar of pickle?
Every rule here is one you tried. Now open your NCERT book. Meet the same ideas in its questions.
Some microbes make people ill. Next is Health: The Ultimate Treasure. It tells how the body fights back.