Hint: Fermentation occurs in yeast cells and bacteria as well as animal muscles. This is an anaerobic pathway to break down glucose. The tiny level of respiration in our body, namely the respiration in cells, is called cellular respiration.
The fermentation is carried out under aerobic or anaerobic conditions. Any type of cellular respiration begins with glycolysis, in which 3 -C molecule pyruvate is formed as the final product. Different cells process this pyruvate in two main ways, and fermentation is one of them.
Type of fermentation
There are three different types of fermentation:
i) Lactic acid fermentation: In this way, starch or sugar is converted into lactic acid by yeast strains and bacteria. During exercise, energy consumption is faster than oxygen provided to muscle cells. This leads to the formation of lactic acid and muscle pain.
ii) Alcohol fermentation: Pyruvate is the final product of glycolysis and is broken down into alcohol and carbon dioxide. Wine and beer are produced through alcohol fermentation.
iii) Acetic acid fermentation: The starch and sugar present in grains and fruits will ferment into vinegar and condiments. E.g. Apple cider vinegar.
Saccharomyces cerevisiae is a fungus commonly referred to as baker's yeast. Add yeast cells to the batter of idli and dosa. The fungus undergoes anaerobic fermentation. Fungi use fermentable sugars and convert them into ethanol and carbon dioxide.
The carbon dioxide gas raises the dough and becomes soft and fluffy. Carbon dioxide bubbles are trapped in the dough, and after baking is complete, the bubbles burst and form pores.
Thus, the correct answer is option ‘C’.
Note: Natural fermentation means that you use the grape skins and yeast naturally present on the winery equipment to ferment for you. Some people will perform true natural fermentation, that is, they have never introduced commercial yeast in the wine cellar.