This set of Class 12 Biology Multiple Choice Questions & Answers (MCQs) focuses on “Microbes in Household Products-2” for Schools.
1. Which of the following is not a type of cheese?
Explanation: Cheese is pressed and flavoured milk curd and more than 2000 varieties of cheese are known. Some of the types include Raw cheese, cottage cheese, Swiss cheese, camembert cheese, Roquefort cheese, etc.
2. Which of the following statements is not related to cottage cheese?
a) Ripened soft cheese
b) Prepared by inoculating skimmed milk first
c) Rennin or chymosin are added
d) Cheese culture of Streptococcus lactis is used
Explanation: Cottage milk cheese is an unripened soft cheese which is prepared by inoculating skimmed milk first with cheese culture of Streptococcus lactis and then rennin or chymosin which is obtained from a fungus source.
3. Which of the following is not a type of ripened cheese?
a) Soft cheese
b) Semi-soft cheese
c) Hard cheese
d) Unbreakable cheese
Explanation: Ripening of cheese is carried out to provide cheese with a characteristic texture, flavour and taste. There are three types of ripened cheese- soft cheese, semi-soft cheese and hard cheese.
4. Moisture content in soft cheese is about 75 per cent.
Explanation: Moisture content in soft cheese is about 50 per cent, e.g., Camembert cheese, in semi-soft cheese is about 45 per cent, e.g., Roquefort cheese and hard cheese is about 40 per cent, e.g., Cheddar cheese.
5. Which of the following helps in the ripening of Camembert cheese?
a) Penicillium roquefortii
b) Propionibacterium sharmani
c) Penicillium camembertii
d) Leuconostoc citrovorum
Explanation: Ripening of cheese is carried out with the help of specific microbes. For example, Camembert cheese is ripened with the help of Penicillium camembertii. Roquefort cheese and Swiss cheese are ripened with the help of Penicillium roquefortii and Propionibacterium sharmani respectively.
6. Which of the following statements is incorrect regarding sausages?
a) These are fermented meats
b) Their taste depends upon the fermenting agent
c) The lactic acid bacterium is the least favoured bacterium
d) Lactic acid bacterium preserves sausages
Explanation: Sausages are fermented meats which possess particular flavour and its taste depends upon the fermenting agent. The most commonly employed microbe is a lactic acid bacterium. The bacterium also preserves the sausages.
7. The LAB plays no role in the stomach.
Explanation: A small amount of curd added to the fresh milk as inoculum contains millions of LAB, which at suitable temperatures multiply, thus converting milk to curd, which also improves its nutritional quality by increasing Vitamin B12. In our stomach too, the LAB plays a very beneficial role in checking the disease-causing microbes.
8. Which of the following statements is not related to toddy?
a) Prepared by fermentation of coconut water
b) Traditional drink in some parts of Northern India
c) Jaggery is produced by boiling it
d) Arrack is obtained from toddy
Explanation: Coconut water is fermented to produce a refreshing drink called toddy. It is a traditional drink in some parts of Southern India. Palm sugar or jaggery is produced by boiling it. Arrack is obtained by the distillation of fermented toddy.
9. Who discovered pasteurisation?
a) Arthur Eddington
b) Ernst Haeckel
c) Carl Woese
Explanation: In 1864, Pasteur discovered the process of pasteurisation. It is a process of preservation of milk, wine and other liquids by heating for a short period and then cooling suddenly. This kills most of the microbes.
10. Which of the following is also known as Single Cell Protein?
Explanation: Live microbial food is called as probiotics, therefore single-cell protein is also referred to as probiotics. It is protein-rich microbial biomass which can be used as food and feed.
11. Which of the following statement is the only correct statement regarding single-cell protein?
a) SCP has all the non-essential amino acids
b) Only autotrophs are used as SCP
c) Fat content is high
d) The protein content is high
Explanation: SCP has all the essential amino acids. Both autotrophs and heterotrophs are used as SCP. SCP is low in fat content and high in protein content.
12. Which of the following is used amongst heterotrophs as SCP?
Explanation: Amongst heterotrophs, yeast and mushrooms are being raised as SCP. There is increasing use of low-cost organic matter for raising SCP like filamentous fungus and common mushrooms.
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