Page 24 - Science Class 08

Advantages of Food Preserva on v It reduces wastage of food.

v It increases the period of storage of the v It increases the food supply and food can
food. be stored for a longer period.

v It increases the availability of food in every
season.

Microbe : A short term for a micro-organism especially for that causes disease
Cyst : The hard outer covering that develops round the body of a microbe
Host : The organism on whose body a parasitic organism feeds

Antibiotic : A substance that prevents the growth of or destroys a disease-causing microbe
Mildew : A kind of fungi that destroys clothes, paper and even wood

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i Microbes are tiny living beings that cause diseases in human beings, animals and plants.
i Microbes can survive in all environments, can multiply very fast, are very tough, but they
are useful too.
i Five common groups of microbes are bacteria, fungi, algae, protozoa and viruses.

i Microbe could be discovered only after the invention of the microscope.
i Microbes live on body-surfaces, in the noses, mouths, throats and digestive canals of human
beings and animals only.
i Microbe can be reared on PDA (Potato Dextrose Agar).
i Bacteria are of four chief kinds— bacilli, cocci, vibrio and spirilla.

i Bacteria are harmful, but most of them are useful.
i Fungi are flora (plants) that lack chlorophyll and so cannot make their food.

i Algae are a group of organisms that develop in wet places.
i Protozoa falls into four classes— flagellates, sarcodines, ciliates and apicomplexans.
i Viruses are microbes that live in the cells of other organisms.

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A. Tick (3) the correct op on.
1. ____________ are ny forms of life that surround us and too small to be seen by the
naked eyes.
(a) Microbes (b) Virus
(c) Protozoa (d) Bacteria

24 Science-8