Assertion (A): Microbes especially yeasts have been used for the production of beverages like wine, beer, whisky, brandy or rum.
Reason (R): The yeast Saccharomyces cerevisiae is used for bread-making and commonly called baker’s yeast.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → The A and R both are true but R is not the correct explanation of A.
Assertion (A): Microbes especially yeasts have been used for the production of beverages like wine, beer, whisky, brandy or rum. — True. Yeasts have been used from very old times to ferment malted cereals and fruit juices and produce these alcoholic drinks.
Reason (R): The yeast Saccharomyces cerevisiae is used for bread-making and commonly called baker’s yeast. — True. Bread dough is fermented using baker’s yeast, Saccharomyces cerevisiae.
A is about the use of yeasts to make alcoholic beverages. R is about the use of the same yeast in making bread.
Why R does not explain A? R tells us one more use of Saccharomyces cerevisiae, but its use in bread-making is not the reason it is used for drinks. Yeast is used for beverages because it ferments malted cereals and fruit juices to produce ethanol. The two statements describe two separate uses of the same microbe, so both are true, but R is not the correct explanation of A.
NCERT Extract:
Fermented Beverages – “Microbes especially yeasts have been used from time immemorial for the production of beverages like wine, beer, whisky, brandy or rum. For this purpose the same yeast Saccharomyces cerevisiae used for bread-making and commonly called brewer’s yeast, is used for fermenting malted cereals and fruit juices, to produce ethanol.”
Microbes in Household Products – “… Similarly the dough, which is used for making bread, is fermented using baker’s yeast (Saccharomyces cerevisiae).”