Fermentation - class-X

• in certain conditions such as starvation when sufficient amount of glucose is not present in the blood the foremost priority of the body is to provide brain with the sufficient amount of glucose.
• So for the other body parts the energy that is to be provided can be done by the use of other substrates instead of glucose.
• First alternative of glucose is fatty acid which is stored in the body. These fatty acid molecules are converted to acetyl coA by the process of beta oxidation and used in the kerbs cycle to provide the cell with energy.
• Glycerol is also a fatty acid which is used as the other fatty acid in the kerbs cycle.
• Amino acids are the part of protein molecules which are usually not stored in the body but can be used in the kerbs cycle whenever they are provided to the cell.
• Therefore the answer 'all of these' is correct.

Respiration, whether aerobic or anaerobic, involves the breakdown of glucose and the release of carbon dioxide as a byproduct.

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'.

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.

Eduard Buchner was a German chemist who won the Noble prize in chemistry for his chance discovery in 1907. His brother Hans Buchner was a physician who conducted early research on blood proteins that could destroy bacteria. Eduard Buchner assisted his brother in his research. He produced yeast cell-free extracts for his brother who wanted to use them for immunological applications. In order to preserve the protein extract from yeast cells, he added sugar and while doing this he noticed the formation of bubbles. This meant that carbon dioxide and alcohol were being produced. Buchner had obtained an enzyme mixture called zymase from yeast that caused glycolysis and transformed the sugar into alcohol. Thus he discovered zymase, a complex of the enzyme that caused glycolysis in 1903. 

Yeast can respire both aerobically as well as anaerobically. Under anaerobic conditions yeast carries out alcoholic fermentation. Thus, it yields carbon dioxide as a product after this process.

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.

So, the correct answer is ' Lactic acid fermentation '.

Milk is rich in lactose sugar. When it is converted into yogurt, lactose sugar is converted to lactic acid by the action of Lactobacillus.

(i). Respiration is an energy yielding process and takes place by the oxidation of foodstuffs.
(ii) Higher plants and animals require oxygen in order to respire aerobically.
(iii) However, in conditions where oxygen is depleted, these organisms perform anaerobic respiration to obtain energy.

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

Yeast respires anaerobically (in the absence of oxygen) . The process is known as fermentation. Glucose is the respiratory substrate.

Answer is option D i.e. "Oxidative phosphorylation"
Fermentation occurs only when there is no oxidative phosphorylation to maintain the production of ATP by glycolysis. During fermentation, pyruvate is metabolized to various compounds such as lactic acid, ethanol and carbon dioxide or other acids. Also, fermentation reactions occur in the cytoplasm while oxidative phosphorylation occurs in mitochondria.

• Fermentation can be defined as the partial breakdown of glucose to produce ethyl alcohol and carbon dioxide.
• It releases energy in form of  ATP molecules.
• 2 ATP molecules are produced per glucose.
  
• 2NADH molecules provide energy which converts pyruvate into lactic acid.
  
• The maximum concentration of alcohol in alcoholic beverages is 15%-16%.
• Option C and E are incorrect statements.
• So, the correct answer is'2'.

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.  

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.

In fermentation, unlike aerobic respiration where oxygen is the terminal electron acceptor, an organic molecule acts as the final electron acceptor to regenerate NAD+ from NADH.

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.

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.

Fermentation is incomplete oxidation of food substances in absence of oxygen (external electron acceptor) into alcohol or lactic acid with the small amount of energy being released. Aerobic respiration uses oxygen as an electron acceptor for oxidation of substrates. Glycolysis is the first common stage of both fermentation and aerobic respiration. Photorespiration is oxidation of RuBP by enzyme RUBISCO and does not produce energy. Thus, the correct answer is option C.

The type of fuel used during physical activity also depends on the efficiency with which oxygen is delivered to muscle cells. The complete breakdown of glucose occurs when $O _2$ is present which is called as aerobic metabolism. When $O _2$ is unavailable, glucose breakdown is incomplete and it results in the formation of lactic acid. Accumulation of lactic acid leads to sore muscles. 
Incomplete breakdown of glucose does not result in the formation of alcohol, water or $CO _2$. 

Agricultural waste, which is rich in cellulose and starch, is commonly fermented by microorganisms to produce ethanol as a biofuel.

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. 

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.

The process of anaerobic respiration takes place in the absence of oxygen. In this type, glucose is oxidized to ethyl alcohol, and it releases carbon dioxide. For example, breathing in yeast is a type of anaerobic respiration.

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.

Fermentation is an anaerobic process, meaning it occurs in the absence of oxygen. Therefore, stating that it requires oxygen is untrue.

In anaerobic conditions, glycolysis produces NADH. To continue glycolysis, NADH must be oxidized back to NAD+, which occurs during the fermentation process.

The breakdown of glucose to form ethanol and carbon dioxide is known as alcoholic fermentation. This takes place in the cytoplasm of cells. The substrate is glucose which undergoes glycolysis to form pyruvate. This pyruvate is then converted into acetaldehyde after the removal of one carbon and then ethanol is formed along with carbon dioxide.

• Lactic acid fermentation does not involve decarboxylation and results in the production of lactic acid and NAD$^{+}$.
  
• Alcoholic fermentation involves decarboxylation and produces CO$ _{2}$ along with ethanol.
  
• Aerobic respiration uses oxygen and glucose to produce CO$ _{2}$ and water as shown below:
        C$ _{6}$H$ _{12}$O$ _{6}$ + 6O$ _{2}$ $\rightarrow$ 6CO$ _{2}$ + 6H$ _{2}$O + energy (heat and ATP)

Fermentation is a type of anaerobic respiration in which the glucose is converted to release gases, acids and alcohols.

In lactic acid fermentation, the 3-carbon pyruvate is converted to the 3-carbon lactic acid. Also NAD$^{+}$ is regenerated in the process, allowing glycolysis to continue to make ATP in anaerobic conditions. Hence lactate and NAD$^{+}$ are the direct products and ATP is the indirect product of lactic acid fermentation. NADH act as a reducing agent here, while CO$ _{2}$ is a product of alcohol fermentation.

Answer is option A i.e. "Pasteur effect"
Pasteur effect is exhibited in yeast cells during anaerobic fermentation. Pasteur effect influences the rate of glycolysis and occurs in presence of oxygen which  decreases the rate of sugar breakdown in yeast.
While, Blackman's law and Emerson effect is related to determining the rate of  photosynthesis. Chargraff's rule is a rule for base equivalence in DNA.

A) Lactic acid fermentation is the process that occurs after glycolysis when there is lack of oxygen.

Fermentation is a type of anaerobic respiration in which the glucose is broken down into pyruvic acid in the absence of oxygen. During fermentation of sugars, this pyruvic acids coverts to a 2C acetaldehyde and then to ethanol and CO₂. All this takes place in the cytoplasm.

Unicellular organisms like yeast undergo an alternate pathway of respiration in which an organic substrate is broken down in absence of oxygen. The end products are alcohol and CO$ _2$. Such a process is called alcoholic fermentation. In Yeast, the fermentation products are ethyl alcohol and carbon dioxide.

Conversion of sugar to alcohol directly was found in yeast fermentation in which glucose was converted to ethyl alcohol and CO$ _2$. The conversion happens in presence of an enzyme called zymase which is found naturally in yeast. So, the answer is 'Zymase'.

Cellular respiration in animals is predominantly aerobic in nature. However in stressful conditions, the respiration turns anaerobic to meet the energy demands. End products of anaerobic respiration are lactic acid and water. End products in plants for aerobic respiration are alcohol and carbon dioxide.

Fermentation is a type of anaerobic respiration that occurs in both plants and animals in the absence of oxygen. The end product is ethyl alcohol in plants and lactic acid in animal cells along with release of CO$ _2$ and energy. Fermentation is not as much energy yielding as aerobic respiration.

Fermentation is a type of anaerobic respiration in which the breakdown of glucose takes place to release acids, alcohols and other gases in absence of oxygen. It takes place in the cytoplasm.

The given process is alcoholic respiration and is done by the yeast in which two molecules of ATP, carbon dioxide and alcohol is released and the process takes place in the absence of oxygen.

Alcoholic fermentation employs the conversion of pyruvic acid to ethanol for the release of energy. This is an incomplete oxidation in which aldehyde is first formed as an intermediate which is then further oxidised to alcohol. Pyruvic acid to acetaldehyde conversion is brought about by pyruvate decarboxylase which releases CO2.

Alcoholic fermentation occurs in the absence of O2 and is a type of anaerobic respiration in which the end products are CO2 and alcohol. Aldehyde is an intermediate product in fermentation and is further oxidised to alcohol with the help of an enzyme called dehydrogenase. So ethanol is formed from acetaldehyde with the help of alcohol dehydrogenase.

In lactic acid fermentation which occurs in the absence of oxygen like fermentation after glycolysis form lactate which gets deprotonated to form lactic acid while in fermentation acetaldehyde converts into alcohol by deprotonation of it.

The Pasteur effect is the inhibition of fermentation in the presence of oxygen, which is observed in facultative anaerobes like yeast (Saccharomyces).

Glycolysis the common pathway of lactic acid fermentation, alcoholic fermentation and aerobic respiration in which glucose is converted into pyruvic acid in a multi-step reaction which includes ten major steps involve various enzymes.

 Alcoholic respiration is done by the yeast in which two molecules of ATP, carbon dioxide and alcohol is released and the process takes place in the absence of oxygen.

The Pasteur effect describes the observation that yeast consumes glucose much faster under anaerobic conditions than under aerobic conditions, effectively inhibiting fermentation when oxygen is present.

Fermentation of carbohydrates such as glucose, lactose, sucrose produces lactic acid.

Anaerobic respiration involves the incomplete breakdown of glucose. It releases around 5% of the energy released by aerobic respiration, per molecule of glucose. In yeast it can be observed, as alcoholic fermentation. 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.

Anaerobic respiration starts with the process of glycolysis. The NADH2 thus formed from glycolysis are used to further oxidise acetaldehyde to form alcohol and CO2. The NAD formed are then recycled back to be used in glycolysis.

During strenuous exercise, muscle cells undergo anaerobic respiration where pyruvic acid is converted into lactic acid to regenerate NAD+.

Fermentation is an energy releasing process in which substrate like sugar is oxidized into organic acids or alcohol without an external electron acceptor. The final electron acceptor is either acetaldehyde or pyruvate. Aerobic respiration is a process in which energy is produced in the presence of oxygen. Glycolysis is a process of converting glucose into two molecules of pyruvate. Photorespiration is a process in which RuBisCO enzyme oxygenates RuBP by wasting some amount of energy.

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.

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.

Beer and wine are produced by fermenting glucose with yeast. Yeast contains enzymes, that catalyze the breakdown of glucose to ethanol and carbon dioxide.

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.

Continuous addition of sugar is a common process in fed-batch fermentation. It is usually done to purify the enzymes involved.

Fermentation is an anaerobic process in which energy can be released from glucose even though oxygen is not available. Fermentation occurs in yeast cells, and a form of fermentation takes place in bacteria and in the muscle cells of animals.
So, the correct answer is option A.

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.

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.

A) Zymase causes the breakdown of sugars into alcohols.

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. 

Respiration is of two types :

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

• 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.
  

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

• 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.
  

• 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.
  

• 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.
  

Respiration is of two types -

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.

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

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$'.

During aerobic respiration, oxygen is consumed and carbon dioxide is released. The ratio of the volume of carbon dioxide given out to the volume of oxygen absorbed in respiration, i.e., CO$ _2$/O$ _2$ is called respiratory quotient (RQ) or respiratory ratio.  in anaerobic respiration, CO2 is evolved but O2 is not consumed, and therefore RQ is infinite (∞).

Saccharomyces is used in fermentation is alcohol. Saccharomyces will be grown in anaerobic conditions same as growth takes place in aerobic conditions.

The fermentation process is catalyzed by enzyme Zymase which converts sugar to ethanol and carbon dioxide.

The production of ethanol is called alcohol fermentation. The very first reaction catalyzed by a cytoplasmic enzyme, pyruvate decarboxylase.

Fermentation process is catalyzed by enzyme Zymase which converts sugar to ethanol and carbon dioxide.

Following glycolysis, if the oxygen is available, end products of glycolysis directly enter Krebs' cycle for further oxidation and energy production. In anaerobic conditions, it chooses to get fermented and the end product is another organic substance which is incompletely oxidised, producing less energy.

During the process of fermentation in the dough, the bacteria and yeast, convert carbohydrates to carbon dioxide resulting in the formation of gas bubbles. The gas bubbles expand inside the dough making it appear larger, which is called leavening. 

The process of fermentation is the form of anaerobic respiration carried by some microorganisms. Many microorganisms such as fungus and bacteria can grow and flourish in the complete absence of oxygen. Such microorganisms can utilize sugars to convert it into ethanol and evolve carbon dioxide. Since it is the incomplete breakdown of glucose, it yields small amount of energy which is sufficient to maintain the life of organisms like yeast and bacteria. 

The process of fermentation is the form of anaerobic respiration carried by some microorganisms. Many microorganisms such as fungus and bacteria can grow and flourish in the complete absence of oxygen. Such microorganisms can utilize sugars to convert it into ethanol or other products and evolve carbon dioxide. Cruickshank used the term 'fermentation' for this process of anaerobic respiration by the microorganisms. 

Both ethyl alcohol (ethanol) and lactic acid are common end products of the metabolic process known as fermentation.

Fermentation is a metabolic process occurs in yeast and bacteria. It occurs in the absence of oxygen. The products produced by yeast includes carbon dioxide, water and ethanol. Glycolysis is the first step of fermentation pathways as well which produces pyruvate, however other steps Kreb's cycle etc. does not take place in the absence of oxygen. Hence option D is correct.

Fermentation is the process of anaerobic respiration, which is carried out by some fungi and bacteria. Fermentation also occurs in muscles of higher vertebrates. In these tissues, it is lactic acid fermentation. Fungi and bacteria carry out alcoholic fermentation (yeast).

Respiration is the catabolic process in which reduced substrates are broken down. The process of respiration can occur in presence of oxygen (aerobic respiration) or absence of oxygen (anaerobic respiration). The process of anaerobic respiration is also called as fermentation. In some microorganisms like yeast, the process of anaerobic respiration (fermentation) results in incomplete breakdown of glucose to ethanol and carbon dioxide.