Tag: introduction to microbiology

Questions Related to introduction to microbiology

During its formation, bread becomes porous due to CO$ _2$ released by

  1. Protozoans

  2. Bacteria

  3. Yeast

  4. Viruses


Correct Option: C
Explanation:

Bread is prepared from the dough, which is fermented using baker's yeast ( Saccharomyces cerevisiae ). The puffed-up appearance of dough is due to the production of carbon dioxide during fermentation. Carbon dioxide gas along with ethyl alcohol evaporate during baking, making bread porous and soft. 

So, n2
So, the correct answer is 'Yeast'

Mostly bread is semi-sweet in taste due to.

  1. Yeast

  2. Remnants of alcohol

  3. Sugar

  4. Acetic acid


Correct Option: B
Explanation:

In the making of bread both carbon dioxide and alcohol are trapped by the dough and both are expelled from the dough by the heat of baking. So, the bread tastes semi-sweet.

So, the correct answer is 'Remnants of alcohol'.

Viruses are useful for making breads.

  1. True

  2. False


Correct Option: B
Explanation:

  • Yeast is used as a leavening agent in bread making. Yeast converts sugars present in the dough to carbon dioxide.
 Due to this, the dough expands. When such dough is baked then air pockets formed due to carbon dioxide will give soft and spongy texture to the bread. The virus is not used for making bread as it lacks respiration. 

Thus, the correct answer is option B.

Which of the following microorganisms converts milk into curd ?

  1. Yeast

  2. Aspergillus

  3. Penicillium

  4. Bacteria


Correct Option: D
Explanation:

Lactobacillus converts milk into curd. It acts on the lactose of the milk and turns it into lactic acid. The increased acidity leads to the coagulation of casein protein of the milk and turns it into curd.

So, the correct answer is option D.

Which of the following statements regarding antibiotics is not correct?
(i) Antibiotics are the attenuated microorganisms which in small concentration can kill or retard the growth of other harmful microorganisms.
(ii) Penicillin was the first antibiotic discovered by Alexander Fleming (1928) while working on bacterium Staphylococcus aureus.
(iii) The full potential of penicillin as an effective antibiotic was established by Ernest Chain and Howard Florey.
(iv) Fleming, Chain and Florey were awarded the Nobel Prize in 1945. 

  1. (i) only

  2. (iii) only

  3. (ii) and (iv)

  4. (i), (iii) and (iv)


Correct Option: A

Match column I with column II and select the correct option from the given codes.

Column I Column II
A. Aspergillus niger (i) Ethanol
B. Clostridium butylicum (ii) Statins
C. Saccharomyces cerevisiae (iii) Citric acid
D. Trichoderma polysporum (iv) Butyric acid
E. Monascus purpureus (v) Cyclosporin
  1. A - (iv), B - (v), C - (ii), D - (i), E - (iii)

  2. A - (iii), B - (iv), C - (i), D - (v), E - (ii)

  3. A - (iii), B - (iv), C - (v), D - (i), E - (ii)

  4. A - (ii), B - (iii), C - (iv), D - (v), E - (i)


Correct Option: B
Explanation:
 Column I  Column II
 Aspergillus niger  Citric acid (commonly used as vinegar)
 Clostridium butylicum  Butyric acid
 Saccharomyces cerevisiae  Ethanol (commercial production of ethanol)
 Trichoderma polysporum  Cyclosporin (Immuno-suppressive agent in organ transplant patients)
 Monascus purpureus  statin (blood cholesterol lowering agent)

Benzo-diazepene is an?

  1. Anti depressant

  2. Anti psychotic

  3. Anti anxiety drug

  4. Sedative


Correct Option: A

Which of the following is the microbe used in manufacturing vinegar?

  1. Streptococcus thermophilus

  2. Saccharomyces cerevisiae

  3. Acetobacter

  4. Aspergillus oryzae


Correct Option: C
Explanation:

The bacteria Acetobacter aceti is involved in the conversion of ethanol formed during fermentation into vinegar. This can happen when Acetobacter bacteria acts on alcoholic beverages such as wine and, therefore, vinegar may also be an undesirable product formed during alcoholic beverage production.