BIOLOGY

20.   Estimate the maximum number of ATP molecules that can be generated during cellular respiration. answer:   Cellular respiration: Cellular respiration is an important process, during which organisms utilize oxygen to metabolize food molecules to supply biochemical energy for cell processes. The processes of cellular respiration involve glycolysis, Krebs cycle, and electron transport chain. For every glucose molecule, the overall ATP output from full oxidation is 36 or 38 ATP. Glycolysis produces two ATP molecules. While Krebs' cycle produces two GTP molecules. These two GTP molecules are therefore turned into two ATP molecules. Electron Transport System generates 32 or 34 ATP molecules and is the cell's main source of energy. Thus, the electron transport system produces the most ATP in cellular respiration.

  19.Elaborate the reactions of the electron transport chain with a note on the electrochemical gradient. answer: Electron Transport Chain: An Introduction The electron transport chain is a protein cluster that transfers electrons through a membrane within mitochondria to form a proton gradient that drives the production of adenosine triphosphate (ATP). The cell uses ATP as an energy source for metabolic processes and cellular functions. In mammalian cells , the electron transport chain (ETC) is the primary O 2 consumer. The ETC is responsible for transporting electrons from NADH and FADH 2 to protein complexes and mobile electron carriers. In the ETC, Coenzyme Q (CoQ) and Cyt c are mobile electron carriers, and O 2 is the final electron recipient. What is the Electron Transport Chain? The electron transport system occurs in the mitochondrial cristae, which contains a number of cytochromes and coenzymes. These cytochromes and coenzymes act as transporter atoms, moving part...

  17.Demonstrate the three reactions that result in substrate level phosphorylation during cellular respiration. answer: During glycolysis, four molecules of ATP are generated from one molecule of glucose, and two molecules of ATP are formed in two Krebs cycles through substrate-level phosphorylation. The phosphate group is transported straight from a substrate to ADP, resulting in ATP. The following are some of them: When 1,3-diphosphoglycerate is converted to 3-phosphoglycerate, 2 ATP is produced. When 2-phosphoenol pyruvic acid converts to pyruvic acid, 2 ATP is produced. When succinyl CoA is converted to succinate, two ATP molecules are produced in two Krebs cycles. GTP is formed by converting GDP to GTP, which subsequently transfers phosphate to ADP to produce ATP. Final answer: 6  ATP are formed through substrate-level phosphorylation from one molecule of glucose when it is completely oxidized.

  15.    Redox reactions may transfer electrons alone or as hydrogen atoms. Justify with a suitable example. answer: 2 N a ( s ) + H 2 ​ ( g ) → 2 N a H ( s )  is a redox change. The half reaction is: 2 N a ( s ) → 2 N a + ( g ) + 2 e − The other half reaction is: H 2 ​ ( g ) + 2 e − → 2 H − ( g ) This splitting of the reaction into two half-reactions automatically reveals here that sodium is oxidized and hydrogen is reduced. Any substance which loses electron is oxidized and gains electron is reduced hence is the case of sodium and hydrogen atoms respectively. Therefore, the complete reaction is a redox change.