Differentiate between Glycolysis and Fermentation
Important Points to Remember in Chapter -1 - Respiration in Plants from NCERT BIOLOGY Textbook for Class XI Solutions
(i) Respiration in plants is different from that of animals as plants do not have any special system for gaseous exchange.
(ii) Stomata and lenticels allow gaseous exchange by diffusion.
(iii) Respiration is a process in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide from the oxidation of complex organic substances.
(iv) Glucose is the favoured substrate for respiration but fats and proteins can also be broken down to yield energy.
(v) In the case of carbohydrates and fats, it is called floating respiration.
(vi) In case of proteins, it is termed protoplasmic respiration.
(vii) Respiration can be aerobic or anaerobic.
(viii) Cellular respiration is an enzymatically controlled stepped chemical process in which glucose is oxidised inside the mitochondria to produce energy-rich ATPmolecules with high-energy bonds.
2. Glycolysis:
(i) Embden, Meyerhof, and Parnas gave it in 1930.
(ii) It is the first stage of the breakdown of glucose in the cell and a common pathway in both aerobic and anaerobic respiration.
(iii) In both types, the initial phase occurs in cytoplasm, called glycolysis.
(iv) Each glucose molecule is broken through a series of enzyme-catalysed reactions into two molecules of pyruvic acid by a process called glycolysis.
(v) The fate of the pyruvate depends on the availability of oxygen and the organism.
3. Fermentation:
(i) Under anaerobic conditions, either lactic acid fermentation or alcohol fermentation occurs.
(ii) Fermentation takes place under anaerobic conditions in many prokaryotes, unicellular eukaryotes, and in germinating seeds.
4. Aerobic Respiration:
(i) Under aerobic conditions, in eukaryotic organisms, the pyruvic acid is transported into mitochondria where it is converted to acetyl Co-A through oxidative decarboxylation.
(ii) Acetyl Co-A is the link between glycolysis and the Krebs cycle (TCA cycle).
(iii) The electrons move through energy carriers and release energy at various points to synthesise ATP by a process called oxidative phosphorylation.
(iv) In oxidative phosphorylation is the ultimate acceptor of electrons and it gets reduced to water.
5. Amphibolic Pathway:
(i) The respiratory pathway is an amphibolic pathway as it involves both anabolism and catabolism.
(ii) The total net gain of ATP in aerobic respiration in eukaryotes is ATP while in prokaryotes it is ATP.
6. Respiratory Quotient:
(i) The ratio of the volume of evolved to the volume of consumed in respiration is called Respiratory Quotient (RQ).
(ii) The respiratory quotient depends upon the type of respiratory substance used during respiration.
(iii) R.Q. value of proteins is 0.8 to 0.9 and fats is 0.7.
(iv) For organic acids R.Q. value is more than 1.
(v) R.Q. is infinity when there is anaerobic respiration.
