Biology

Microorganisms in Food Production

1,086 Questions

Microorganisms play a vital role in food production through processes like fermentation and bioprocessing. Questions on this topic cover the use of yeast, bacteria, and industrial microbiology. These concepts are important for science sections in various competitive exams.

Alcoholic fermentationDairy beverage productionIndustrial ethanol preparationCitric acid productionBiodigester temperature

Microorganisms in Food Production Questions

Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production

Production of alcohol by yeast fermentation is 

  1. Anaerobic

  2. Aerobic

  3. Light dependent

  4. Both A and C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yeast fermentation is a type of anaerobic respiration in which the substrate is oxidised in absence of oxygen. The intermediate product is acetaldehyde and final products are ethyl alcohol and CO$ _2$. It is also known as alcoholic fermentation. So the answer is 'Anaerobic'.

Multiple choice biology life processes in living organisms- part 1 fermentation cell respiration living organisms and energy production

What could be the reason for maida flour to increase in size?

  1. Fermentation

  2. Preservation

  3. Fumigation

  4. Both A and B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fermentation is an anaerobic process by which glucose is broken down into alcohol, carbon dioxide, hydrogen gas. Yeast is used during baking process. This process is responsible for the increasing the size of maida dough because yeast converts sugar into carbon dioxide and ethanol. Carbon dioxide gas is trapped by gluten proteins which causes dough to rise.

Thus, the correct answer is 'Fermentation.'

Multiple choice biology life processes in living organisms- part 1 fermentation cell respiration living organisms and energy production
Dough kept overnight in warm weather becomes soft and spongy due to
  1. Absorption of ${CO} _{2}$ from atmosphere

  2. Imbibition

  3. Fermentation

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Fermentation can be described as an enzyme-catalyzed process in which one substrate is usually broken down by the enzymes produced by bacteria, yeast, and other microorganisms. Fermentation of glucose results in the formation of ethanol and carbon monoxide. This is an exothermic reaction and results in the release of energy. The changes observed in dough after keeping it overnight in warm weather is an example of fermentation.
Thus, the correct answer is 'fermentation.'
Multiple choice biology life processes in living organisms- part 1 fermentation cell respiration living organisms and energy production

Which of the following is incorrect about fermentation?

  1. Toddy is made by fermenting sap from palms.

  2. Propionibacterium is used to ferment the cheese.
  3. The puffed-up appearance of dough is due to the production of ${ CO } _{ 2 }$.

  4. Fermentation in muscles produces alcohol.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A. Toddy is created by fermenting the saps of various species of palm trees such as the palmyra, date palms, and coconut palms.
B. Swiss cheese is obtained by propionic fermentation which occurs due to the propionibacteria.

C.  The yeast added to flour reproduces rapidly and produces carbon dioxide gas which gives a puffed-up appearance.
D. Fermentation in muscle cells produces a waste product called lactic acid which contributes to the fatigue in muscles.

So, the correct answer is 'Fermentation in muscles produces alcohol'.

Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production

In alcohol fermentation

  1. Triose phosphate is the electron donor while acetaldehyde is the electron acceptor

  2. Triose phosphate is the electron donor while pyruvic acid is the electron acceptor

  3. There is no electron donor

  4. Oxygen is the electron acceptor
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In alcohol fermentation, the pyruvic acid (triose phosphate) produced through glycolysis is subjected to the oxidative decarboxylation, wherein the pyruvic acid is converted to the acetaldehyde. The acetaldehyde accepts the electrons and is reduced to form the alcohol or ethanol. There is no external electron acceptor involved as in case of aerobic respiration

So, the correct answer is 'triose phosphate is the electron donor while the acetaldehyde is the electron acceptor'

Multiple choice biology life processes in living organisms- part 1 fermentation cell respiration living organisms and energy production

Fermentation is carried out by

  1. All bacteria

  2. All fungi

  3. Some bacteria and some fungi

  4. All micro-organisms
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fermentation is incomplete oxidation of food substances into alcohol and lactic acid with the small amount of energy being released. Both lactic acid and ethanol fermentation do not produce oxygen. It is carried out by anaerobic bacteria and fungi. Aerobic bacteria and fungi carry out aerobic respiration. Thus, the correct answer is option C.  

Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production

Which of the following enzymes is not required during fermentation process?

  1. Lactic acid dehydrogenase

  2. Pyruvate dehydrogenase

  3. Pyruvate decarboxylase

  4. Alcohol dehydrogenase
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fermentation is an anaerobic process. Pyruvate dehydrogenase is part of the aerobic link reaction that converts pyruvate to Acetyl-CoA before entering the Krebs cycle, so it is not used in fermentation.

Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production

Which of following is final $e^-$ acceptor in lactic acid fermentation :-

  1. Pyruvic acid

  2. Ethanol

  3. Acetaldehyde
  4. $O _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Under normal aerobic conditions, the final electron acceptor at the end of the electron transport chain is oxygen. However, fermentation occurs when there is no oxygen available. Therefore, something else must act as the final electron acceptor. In lactic acid fermentation, NADH is the electron carrier that ultimately carries them to pyruvate. Pyruvate is reduced to lactic acid, and thus, acted as the final electron acceptor.

So, the correct option is 'Pyruvic acid'.

Multiple choice biology life processes in living organisms- part 1 fermentation cell respiration living organisms and energy production

The product of fermentation is

  1. Ethanol and lactic acid

  2. Acetic acid and lactic acid

  3. Ethanol and acetic acid

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Fermentation is a metabolic process in which an organism converts a carbohydrate, such as starch or a sugar, into an alcohol or an acid. For example, yeast perform fermentation to obtain energy by converting sugar into alcohol. Lactic acid fermentation takes place in muscles during heavy exercise producing lactic acid. The products of fermentation are acetic acid, lactic acid, ethanol etc.

Thus, the correct answer is option D. 

Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production

Fermentation is represented by which of the following equation? 

  1. $C _{6}H _{12}O _{6}\, \rightarrow\, 6CO _{2}\, + _\, 6H _{2}O\, +\, 673 K\, cal$
  2. $C _{6}H _{12}O _{6}\, \rightarrow\, 2C _{2}H _{5}OH\, +\, 2CO _{2}$
  3. $6CO _{2}\, +\, 12H _{2}O\, \rightarrow\, C _{6}H _{12}O _{6}\, +\, 6H _{2}O\, +\, 6O _{2}$
  4. $6CO _{2}\, +\, 6H _{2}O\, \xrightarrow[chlorophyll]{light}\, C _{6}H _{12}O _{6}\, +\, 6O _{2}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In fermentation, say by yeast, the incomplete oxidation of glucose is achieved under anaerobic conditions by sets of reactions where pyruvic acid is converted to $CO _2$ and ethanol. The enzymes, pyruvic acid decarboxylase and alcohol dehydrogenase catalyse these reactions. Other organisms like some bacteria produce lactic acid from pyruvic acid. In animal cells also, like muscles during exercise, when oxygen is inadequate for cellular respiration pyruvic acid is reduced to lactic acid by lactate dehydrogenase. In both lactic acid and alcohol fermentation not much energy is released; less than seven per cent of the energy in glucose is released and not all of it is trapped as high energy bonds of ATP. 

Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production

In alcohol fermentation,

  1. Triose phosphate is the electron donor, while acetaldehyde is the electron acceptor.

  2. There is no electron donor.

  3. Oxygen is the electron acceptor.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In alcohol fermentation, NADH (from glycolysis) acts as the electron donor to reduce acetaldehyde into ethanol, while acetaldehyde itself acts as the final electron acceptor.

Multiple choice biology life processes in living organisms- part 1 fermentation cell respiration living organisms and energy production

Fermentation is an

  1. Aerobic respiration

  2. Incomplete oxidation

  3. Excretory process

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The process of respiration can be aerobic or anaerobic. The process of anaerobic respiration is also called as fermentation. Fermentation is a form of anaerobic respiration in which carbohydrates are incompletely oxidised to either ethanol and carbon dioxide as in yeast or lactic acid, as in the muscles of higher vertebrates.