Microbes in Household Products - Curd, Bread, Toddy - Unsolved Practice Set
Chapter: Microbes in Human Welfare | Topic: Microbes in Household Products Curd Bread Toddy
MICROBES IN HOUSEHOLD PRODUCTS - CURD, BREAD, TODDY - UNSOLVED PRACTICE SET
Topic: Microbes in Household Products Curd Bread Toddy
Multiple Choice Questions
Q1. Curd formation from milk is primarily brought about by the bacterium:
- Saccharomyces cerevisiae
- Lactobacillus (lactic acid bacteria)
- Escherichia coli
- Rhizobium
Q2. The souring and thickening of milk into curd occurs due to:
- The bacteria converting milk sugar (lactose) into lactic acid
- The complete removal of all bacteria from milk
- Boiling milk at high temperature
- Adding sugar to milk
Q3. The rising ("puffing up") of bread dough is caused by:
- Bacteria producing lactic acid
- Yeast (Saccharomyces cerevisiae) fermenting sugars and releasing carbon dioxide gas
- Direct heating of the dough
- Addition of preservatives
Q4. Toddy, a traditional fermented beverage in parts of India, is prepared from the fermentation of:
- Milk
- Sap collected from palm trees
- Wheat flour
- Rice water only
Q5. The main microorganism responsible for the alcoholic fermentation seen in preparing toddy is:
- Lactobacillus
- Yeast (Saccharomyces species)
- Rhizobium
- Penicillium
Short Answer Questions
Q6. Name the microorganism responsible for curd formation, and briefly explain how it converts milk into curd.
Q7. Why does bread dough rise before baking? Name the microorganism responsible.
Q8. What is toddy, and which type of microorganism is primarily responsible for its preparation?
Q9. Give one reason why a small amount of curd is traditionally added to warm milk to prepare fresh curd at home.
Long Answer Questions
Q10. Explain the role of Lactobacillus in the preparation of curd from milk, describing the biochemical changes that occur during this process.
Q11. Discuss the role of yeast in bread-making, explaining how fermentation contributes to the texture and rise of the dough.
APPLICATION / ANALYSIS
Q12. A student notices that curd set overnight in a warm kitchen turns out thicker and more sour than curd set in a cold refrigerator over the same period. Explain, using your understanding of Lactobacillus activity, why temperature affects the rate and extent of curd formation.
Q13. A baker forgets to add yeast to their bread dough by mistake, and the bread comes out flat and dense after baking, unlike the usual soft, airy loaf. Explain, using your understanding of fermentation, why the missing yeast caused this outcome.