Tag: fermentation

Questions Related to fermentation

Ethyl alcohol fermentation can be observed in

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

  1. Rhizopus

  2. Lactobacillus

  3. Mesophyll cell

  4. RBC

Show answer
Correct Option: A
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'.
Ethyl alcohol fermentation occurs in _______________.
biology respiration in plants fermentation cell respiration living organisms and energy production

  1. Lactobacillus

  2. Muscles of Humans

  3. Rhizopus

  4. All of these

Show answer
Correct Option: C
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).

Choose the correct answers from the alternatives given :
Which of these is not true of fermentation?

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

  1. Net gain of only two ATP

  2. Occurs in cytosol

  3. NADH donates electrons to electron transport system

  4. Begins with glucose

Show answer
Correct Option: C
Explanation:

  • Fermentation is the process that takes place after the glycolysis in the cells where the anaerobic respiraton occurs due to absence or lack of oxygen.
  • Pyruvic acid which is formed at the end of the glycolysis by the break down of the glucose molecule enters the fermentation reaction in the anaerobic cells.
  • During fermentation reaction the pyruvic acid is converted to lactic acid and one molelcule of NADH is formed per molecule of pyruvic acid.
  • This molecule of NADH will only form ATP when it will undergo oxidative phosphorylation in the electron transport chain which takes place in mitochondria, but for this process presence of oxygen is required so the organisms or the cells performing anaerobic respiration cannot perforem this process therefore the NADH formed will not donate electron to the ETS and no ATP will be formed by that.
  • Therefore the answer option 'NADH donates electrons to electron transport system' is correct.










State whether the following statements are true or false.
Fermentation follows glycolysis in some cells when oxygen is not available.

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

When oxygen is not available to cells due to rapid metabolism without recovery, instant energy is produced by Fermentation but in fewer amounts.

The pyruvate formed is converted into lactic acid during fermentation in the absence of oxygen.
So, the correct statement is 'Fermentation follows glycolysis in some cells when oxygen is not available.'.

State whether the following statements are true or false.
When not enough oxygen gets to muscle cells during a sprint, energy is provided by glycolysis of glucose to pyruvic acid and then conversion of these molecules to lactic acid.

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

  1. True

  2. False

Show answer
Correct Option: A
Explanation:
  • Glycolysis is the first part of both aerobic and anaerobic respiration.
  • The end product of glycolysis is pyruvic acid which is produced in the cytoplasm and no oxygen is required for the process of glycolysis.
  • The pyruvic acid formed can enter either kerb cycle for the reactions of aerobic respiration or it can undergo anaerobic reaction in the cells where there is absence of oxygen.
  • There are 2 process under anaerobic reaction in which pyruvic acid can take part. First is where pyruvic acid is converted to lactic acid and second is where it converted to Ethanol and carbon dioxide. These reaction are called fermentation reaction.
  • Fermentation reaction of pyruvic acid takes place when there is no presence of oxygen. Sometimes during some of the physical activities when not enough oxygen is not reaching the muscles the energy for the contraction and relaxation of the muscles is provided by the process of glycolysis (2ATP) and then the pyruvic acid undergoes fermentation reaction forming Lactic acid and releasing 1 molecule of NADH per Pyruvic acid molecule.
  • Therefore the above sentence is correct and the answer option 'True' is correct.

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

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

  1. Lactobacillus cells

  2. Muscle cells

  3. Sulphate-reducing bacteria

  4. Both (a) and (b)

Show answer
Correct Option: D
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.

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

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

  1. sulphate

  2. pyruvate

  3. acetaldehyde

  4. oxygen

Show answer
Correct Option: C
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.






Choose the correct answers from the alternatives given :
Which of these pairs of processes are anaerobic?

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

  1. Fermentation and glycolysis

  2. Fermentation and the Krebs cycle

  3. Glycolysis and the Krebs cycle

  4. The Krebs cycle and the electron transport system

Show answer
Correct Option: A
Explanation:

Respiration is of two types -

Aerobic respiration - It is the process of complete oxidation of organic foods into carbon dioxide and water in the presence of oxygen. it has three steps ;
  • Glycolysis - It occurs in the cytoplasm in which glucose breaks into two molecules of pyruvate. It occurs in both aerobic and anaerobic respiration.
  • Krebs cycle occurs in the mitochondria where oxidative decarboxylation of pyruvate takes place to form acetyl CoA.
  • Electron transport system - Here series of coenzymes and cytochromes acts as a passage of electron.
Anaerobic respiration - It is the process of incomplete oxidation of organic foods. oxygen is not utilized in this process, this occurs in the process of fermentation.
So, the correct option is ' Fermentation and glycolysis'.

The end products of fermentation are

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

  1. $O _2$ and ethyl alcohol

  2. $O _2$ and acetaldehyde

  3. $CO _2$ and ethyl alcohol

  4. $CO _2$ and acetaldehyde

Show answer
Correct Option: C
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 '
.



During alcoholic fermentation by yeast two molecules of glucose produce.

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

  1. $2$ molecules of ethanol $+2$ molecules of $CO _{2}$

  2. $4$ molecules of ethanol $+ 4$ molecules of $CO _{2}$

  3. $6$ molecules of ethanol $+ 6$ molecules of $CO _{2}$

  4. $3$ molecules of ethanol $+ 3$ molecules of $CO _{2}$

Show answer
Correct Option: B
Explanation:

Alcoholic fermentation is a process of anaerobic respiration in which 2 molecule of glucose is converted to -
4 molecules of ethanol,
4 molecules of carbon dioxide,and
4 ATP.
So, the correct option is '4 molecules of ethanol + 4 molecules of CO$ _2$'.