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

Lactic acid is converted into alcohol in a process called as

  1. Fermentation

  2. Aerobic respiration

  3. Respiration

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

Fermentation is a process used to produce wine, beer, yogurt etc. Yeast performs fermentation to obtain energy by converting sugar into alcohol. Alcoholic fermentation also referred to as ethanol fermentation, is a biological process in which molecules such as glucose, fructose, and sucrose are converted into cellular energy and thereby produce ethanol and carbon dioxide as metabolic waste products.

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

During lactic acid fermentation

  1. $O _{2}$ is used and $CO _{2}$ is liberated
  2. Neither $O _{2}$ is used, nor $CO _{2}$ is liberated
  3. $O _{2}$ is used, but $CO _{2}$ is not liberated

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

Lactic acid fermentation is a biological process by which glucose and other six-carbon sugars are converted into cellular energy and the metabolite lactate. It is an anaerobic fermentation reaction, that occurs in muscle cells. There is no liberation of carbon dioxide in this process.

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

Fermentation refers to

  1. Anaerobic respiration

  2. Incomplete oxidation of carbohydrate

  3. Complete oxidation of carbohydrate

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

The process of respiration can be aerobic or anaerobic. The process of anaerobic respiration is also called 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.

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

In Yeast, anaerobic respiration produces

  1. $CO _2$ and ethanol
  2. $CO _2$ and water
  3. $O _2$ and lactic acid
  4. $O _2$ and pyruvic acid
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yeast can undergo both aerobic respiration or anaerobic respiration. In anaerobic respiration, glucose is utilized and carbon dioxide and ethanol are formed. It is also called as alcoholic fermentation. In aerobic respiration, water and carbon dioxide are produced.

Thus, the correct answer is option A.

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

With reference to the products of microbial fermentation, which one of the following pairs is correctly matched?

  1. Lactic acid- Rhizopus stolonifer

  2. Vinegar- Acetobacter sp.
  3. Vitamin $B12$- Streptomyces griseus

  4. B-amylase- Saccharomyces sp.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rhizopus stolonifer is a fungus known for producing lactic acid through fermentation. While other options have errors (e.g., Acetobacter produces acetic acid, not vinegar directly as a species name), this is the most accurate pairing provided.

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

During lactic acid fermentation

  1. $O _2$ is used, $CO _2$ is liberated
  2. Neither $O _2$ is used nor $CO _2$ liberated
  3. $O _2$ is not used, $CO _2$ is liberated
  4. $O _2$ is used, $CO _2$ is not liberated
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In all organisms, during glycolysis, glucose is used as an energy source and converted into pyruvate, producing ATP and NADH molecules. Lactic acid fermentation is an anerobic metabolic process carried out by few bacteria (Lactobacillus) and animal (i.e., muscle) cells.  Lactate dehydrogenase (enzyme) participates in this process and converts the pyruvate (produced during glycolysis) to lactic acid, thereby regenerating NAD+, which can be returned to the cycle and helps to maintain glycolysis. 

So, the correct option is 'O2O2 is used, CO2CO2 is not liberated'.
CO2

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


Which process produces alcohol or lactate?

  1. Krebs cycle

  2. Glycolysis

  3. Electron transport system

  4. Fermentation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Respiration is of two types :

Aerobic respiration- here oxygen is required for the process to occur. It occurs in the following three steps :
  • Glycolysis
  • Krebs cycle
  • Terminal oxidation
Anaerobic respiration- here oxygen is not required in the process of respiration. In this process, organic food is incompletely degraded without the use of oxygen which later produces ethanol or lactic acid as the end product.
So, the correct option is ' Fermentation'.

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

Ethyl alcohol fermentation can be observed in

  1. <p> Rhizopus</p>

  2. <p> Lactobacillus</p>

  3. Mesophyll cell

  4. RBC
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
While Saccharomyces cerevisiae is the most important source of industrial alcohol, R. stolonifer and other species of Rhizopus also produce ethyl alcohol which is the most important fermentation product.

So, the correct answer is 'Rhizopus'.
Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production
Ethyl alcohol fermentation occurs in _______________.

  1. Lactobacillus

  2. Muscles of Humans

  3. Rhizopus

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ethyl alcohol fermentation occurs in fungi such as Rhizopus, yeast, and bacteria. 

Lactobacillus and muscles of humans do anaerobic respiration but form lactic acid as an end product. (i.e., Lactic acid fermentation)
So, the correct answer is (C).

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

Choose the correct answers from the alternatives given :
Which of the following engage in lactate fermentation?

  1. Lactobacillus cells

  2. Muscle cells

  3. Sulphate-reducing bacteria

  4. Both (a) and (b)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • Lactobacillus baterial are used for the preparation of curd from the milk. These bacterial cells perform the reaction of lactic acid fermentation where they use the lactose in the milk as substrate converting to lactic acid of curd.
  • Muscle cells when they undergo go excessive physical work and there is not enough oxygen to undergo aerobic respiration so they also perform the process of lactic acid fermentation forming lactic acid in the muscles but excessive formation of lactic acid will lead the muscle to go into fatigue condition where the muscle will be no longer able to perform any physical function for atleast some time.
  • Therefore the answer option 'Both (a) and (b)' is correct.
Multiple choice biology respiration in plants fermentation cell respiration living organisms and energy production

Choose the correct answers from the alternatives given :
In alcoholic fermentation is the final acceptor of the electrons stripped from glucose. 

  1. sulphate

  2. pyruvate

  3. acetaldehyde

  4. oxygen
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  • 2 enzymes are present in the alcoholic fermentation of pyruvate they are decarboxylase and alcoholic dehydrgenase.
  • The pyruvate is first converted to acetaldehyde in the presence of decarboxylase enzyme.
  • This acetaldehyde is the final acceptor of electrons and it converts the NADH to NAD so that the process of glycolysis can continue without hinderance.
  • This acetaldehyde is then converted to ethanol in presence of alcohol dehydrogenase.
  • Therefore here the acetaldehyde or the pyruvate are the final acceptor of electron.
  • Therefore options 'pyruvate' and 'acetaldehyde' both can be correct answers.






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

The end products of fermentation are

  1. $O _2$ and ethyl alcohol
  2. $O _2$ and acetaldehyde
  3. $CO _2$ and ethyl alcohol
  4. $CO _2$ and acetaldehyde
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fermentation is the process of partial breakdown of glucose into ethyl alcohol or lactate. It is an anaerobic process. Fermentation takes place through the two types - lactic acid fermentation and alcohol fermentation.

 Name of process  End products
 Lactic acid fermentation   Lactate
 Alcohol fermentation  Ethyl alcohol + CO2

So, the correct answer is ' CO2 and ethyl alcohol '
.