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💡 Fuzz on the bread
Leave a moist roti in a warm, dark corner and by the third day it wears a fuzzy patch. Those are moulds — fungi that arrived as invisible spores drifting in the air.
In this Activity, we will experiment to grow bread mould and observe how fungi reproduce by forming spores.
- Lightly moisten a small slice of bread or a roti with a few drops of water.
- Prepare a moist chamber: line a box with wet cotton and tissue paper, and place the bread on it.
- Keep the chamber in a warm, dark place away from direct sunlight, keeping it moist.
- Observe the bread daily without touching it; after three days look for mould with a magnifying glass.
- With a needle, transfer a little mould to a slide, add cotton-blue stain, observe under the microscope and compare with Fig. 11.8.
What we observe
Thread-like structures with round sacs of tiny
spores
grow on the bread — the mould reproduces by forming huge numbers of spores.
How do fungi reproduce by spores?
- Fungi such as Rhizopus and Aspergillus form spores in a sac-like structure or on a swollen vesicle (Fig. 11.8).
- Spores are light, usually single-celled and produced in huge numbers (millions from one colony).
- They float in air currents and, on reaching a moist, nutrient-rich spot, germinate quickly into new individuals.
Why are the offspring of asexual reproduction called clones?
- The central process behind asexual reproduction is mitosis .
- Mitosis produces two daughter cells with the same number of chromosomes , identical to the parent cell.
- So the offspring are genetically identical to the parent and are called clones ; this is a fast way to increase numbers when conditions are favourable.
NCERT Question 4 — Why does asexual reproduction produce
Why does asexual reproduction produce offsprings that are genetically identical to the parent?
View Answer →
🧵 Threads of Curiosity
- We kept the moist chamber warm, about 25–35 °C.
- Mould spores in the air need warmth and moisture.
- Lower temperatures slow or stop their reproduction.
- That is why we refrigerate perishable food.
- Before refrigerators, fresh food lasted only 1–2 days.
🌎 Bridging Science and Society
- Moulds look unpleasant, but fungi benefit society greatly.
- They grow fast by forming spores.
- They degrade organic wastes and pollutants.
- They even help remove heavy metals from industrial wastes.
- Many antibiotics (penicillin, amoxicillin) come from fungi, saving lives.
- Do you know any fungus that can degrade plastic?
Important Definitions
- Asexual reproduction — reproduction involving a single parent, producing genetically identical offspring.
- Vegetative propagation — new plants arising from the vegetative parts (roots, stems, leaves) of a plant.
- Cutting — growing a new plant from a cut piece of shoot or stem planted in soil.
- Grafting — joining a stem piece of one plant onto a rooted plant so they grow as one.
- Layering — burying part of a twig until it roots, then cutting it to grow as a new plant.
- Tissue culture — growing many plantlets from shoot-tip cells in the laboratory.
- Budding — a bud grows on the parent body, enlarges and separates to live independently.
- Spore — a light, usually single-celled reproductive unit of fungi that germinates into a new individual.
- Mitosis — cell division giving two daughter cells identical to the parent cell.
- Clone — an offspring genetically identical to its single parent.
