Tag: introduction to microbiology

Questions Related to introduction to microbiology

........... is used to make wine and bread.

  1. Amoeba

  2. Yeast

  3. Tradescantia

  4. Rheo leaf


Correct Option: B
Explanation:

Yeast is a single-celled, microscopic fungus which uses sugar as food. Ethanol fermentation is a biological process of converting sugars to alcohol and carbon dioxide. It is performed by yeasts in the absence of oxygen. 

So, the correct answer is option C.

Why yeast is used in baking industry

  1. It reproduces rapidly

  2. Yeast produces carbon dioxide during respiration

  3. Both A and B 

  4. None of these


Correct Option: C

What is the basis of using yeast is baking industry? 

  1. Bubbles of gas fill the dough

  2. Bubbles of gas increase its volume

  3. Both A and B

  4. None of these


Correct Option: C
Explanation:

Yeast reproduces rapidly and produces carbon dioxide during respiration. Bubbles of the gas fill the dough and increase its volume.

........... is used in the making of bread and yoghurt.

  1. Virus

  2. Bacteria

  3. Yeast

  4. None of the above


Correct Option: C
Explanation:

Fermentation is the process which is carried by anaerobic respiration of microorganism which leads to the production of lactic acid or alcohol with the release of carbon dioxide. When the yeast is added to the dough of the bread it converts the sugar to ethanol and carbon dioxide which forms bubbles. Yeast has a lot of economical value to the mankind. It is used in the production of bread, wine, curd etc.

So, the correct answer is option C.

Streptococcus lactis is responsible for

  1. Conversion of molasses into alcohol

  2. Conversion of milk into curd

  3. Tanning of leather

  4. Flavouring the leaves of tea and tobacco


Correct Option: B
Explanation:

Streptococcus lactis is an important bacteria responsible for manufacturing of  dairy product, curd. It converts milk into curd by the process of fermentation. It breaks the sugar present in the milk and produces lactic acid. This lactic acid results in the curdling of the milk proteins and produces curd with a tangy taste.

Thus, the correct answer is 'Conversion of milk into curd.'

The bread becomes soft and porous when the yeast cells are mixed in the lump of dough of wheat flour, because

  1. Yeast is soft and flour also become soft.

  2. Yeast produces acetic acid and alcohol which gives softness to the bread.

  3. Evolution of CO$ _2$ makes the bread spongy.

  4. Yeast produces benzoic acid.


Correct Option: C
Explanation:
  • In the production of bread one of the step is fermentation which is done with the help of the yeast or better know as baker's yeast ie Saccharomyces cerevisiae 
  • At the time of making dough for the bread yeast is added along with other ingredients and is left to rest for sometime which gives yeast time for the fermentation process where it converts the sugar present in the  flour to carbon dioxide and alcohol.
  • When the dough is baked the release of carbon dioxide at the time of baking leaves holes in the bread which gives the bread its sponginess
  • So, the correct answer is 'Evolution of CO22 makes the bread spongy'

Bread dough rises because of the action of

  1. Heat

  2. Kneading

  3. Bacteria

  4. Yeast


Correct Option: D
Explanation:
Bread  dough rises because of the activity of yeast. Yeast uses carbohydrates in the dough as raw material to form energy yielding molecules, releasing $CO _2$ and Ethanol as byproducts. The $CO _2$ trapped in the dough makes the dough fluffy
So, the correct answer is 'Yeast'

One of the following is used in the baking of the bread?

  1. Zygosaccharomyces octosporus

  2. Saccharomyces cerevisiae

  3. Saccharomyces ludwigii

  4. Rhizopus stolonifer


Correct Option: B
Explanation:
  • Saccharomyces cerevisiae also know as Baker's yeast is used in bread making and in production of many other bakery products.
  • It is used for the act of fermentation which is done by the yeast on the sugar/starch that is present in the flour. The starch is converted into alcohol and carbon dioxide by the act of fermentation.
  • The carbon dioxide in the dough makes the bread dough to rise and also provides the bread with softness and makes it fluffy after it is cooked.
  • So, the correct answer is 'Saccharomyces cerevisiae'

Which of the following statement is correct?

  1. Paramoecium and Plasmodium belong to same kingdom as that of Penicillium.

  2. Lichen is a composite organism formed from symbiotic association of an alga and a protozoan.

  3. Yeast used in making beer and bread is a fungus.

  4. Nostoc and Anabaena are examples of protista.


Correct Option: C
Explanation:

Yeast is a fungal species that converts carbohydrates to carbon dioxide and alcohols. Saccharomyces cerevisiae is responsible for the production of ethyl alcohol.

So, the correct answer is 'Yeast used in making beer and bread is a fungus'.

Baker's yeast is?

  1. S. cerevisae

  2. S. ludwingii

  3. S. octosporus

  4. Schizosaccharomyces


Correct Option: A
Explanation:

The yeast most commonly used for leavening bread is Saccharomyces cerevisiae, the same species used for brewing alcoholic beverages. This yeast ferments some of the carbohydrates in the flour, including any sugar, producing carbon dioxide. 

So the correct option is 'S. cerevisiae'.