Question

.
th
us.
Microorganisms - Our friends or
foes?
Fig. 1: Cups containin
bowl do not add anything. Keep the in
In which of the tw
Microorganisms are present in air, water,
bowls in a warm place and observe the mi
added to maida do
soil and within the bodies of animals and
plants. Some microorganisms are very
in the bowls after 5 to 6 hours.
In bakery when yea
useful and help us in many ways while some
• What changes did you observe?
dough for preparing bre:
This is due to the pro
of them are harmful.
. What is the reason for this?
dioxide gas during
In this section we will study about how
Curd or buttermilk contains bacteriun
fermentation. Bubbles
microorganisms help us and how they harm
named Lactobacillus which converts dough spongy in nature
milk into curd.
Activity-3
Useful Microorganisms
Activity-2
Commercial use of
Some microorganisms are very useful
to our everyday life. For example in making
Take 100 grams of maida in a bowl, ad Take two bowls, ha
of curd and in preparation of idly, dosa,
one or two spoons of yeast powder, ad Add 5 to 10 spoons of
bread and cake. Some microorganisms are
some hot water and knead it to make doug then add 2 to 3 spoons
also useful in the preparation of medicines
Keep the dough in a warm place. Obsery of the two bowls. C
required to cure different diseases. Some
the dough after 3-4 hours.
with lids and keep th
After 3 to 4 hours rem
of them are farmer friendly as they
• What changes did you observe in th
the contents.
increase soil fertility. Let us do some
dough?
• What difference
activities to grow microbes and produce
• What might be the reason? Discuss with between the two
products used by us.
your friends and write about it.
• What may be the
You might have observed your mother in yeast mixed b
preparing fermented foods like Idli and This is the c!
Dosa. What could be the reason for alcohol. Sugars are
prepearing Idli and Dosa dough a day before by yeast. This pro-
cooking it?
sugars into alcc
fermentation. This
‘ge scale in the r
Activity-1
Take some lukewarm milk in two small
bowls. Add a few drops of butter milk or
little curd in one of the bowls. In the second​

Answer 1

Answer:

helps the mass to build an opinion about the happenings around them. 5) It caters to persuade people in their beliefs, opinions, attitudes and thinking on several issues like voting, religious convictions, culture etc. 6) It educates us. 7) It entertains us and provide pleasure by the various media broadcasts.