Question
QUESTION 3 (a) State two (2) types of respiration. [ 2marks] (b) State the major differences between the two types of respiration mentioned in (a). [10 marks] (c) Describe the phases of Krebs cycle that produces carbon dioxide and ATP.
Answer
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Scarlett
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Answer
1. (a) Aerobic respiration, Anaerobic respiration.2. (b) - Oxygen Requirement: Aerobic requires oxygen; anaerobic does not. - Energy Yield: Aerobic produces more ATP; anaerobic produces less ATP. - End Products: Aerobic produces CO2 and H2O; anaerobic produces lactic acid or ethanol and CO2. - Location: Aerobic occurs in mitochondria; anaerobic occurs in cytoplasm. - Process Duration: Aerobic is longer; anaerobic is quicker.3. (c) - Decarboxylation: Isocitrate to α-ketoglutarate and α-ketoglutarate to succinyl-CoA, releasing CO2. - ATP Production: Conversion of succinyl-CoA to succinate, producing ATP.
Explanation
1. Types of Respiration: Respiration is a biochemical process in which energy is released from organic compounds. There are two primary types of respiration: aerobic and anaerobic respiration. a. Aerobic Respiration: This occurs in the presence of oxygen. It involves the complete breakdown of glucose into carbon dioxide and water, releasing a significant amount of energy, which is stored in the form of ATP (Adenosine Triphosphate). b. Anaerobic Respiration: This process occurs in the absence of oxygen. It leads to the partial breakdown of glucose into substances like lactic acid (in animals) or ethanol and carbon dioxide (in plants and yeast). The energy yield in anaerobic respiration is much lower compared to aerobic respiration.2. Major Differences Between Aerobic and Anaerobic Respiration: a. Oxygen Requirement: Aerobic respiration requires oxygen, while anaerobic respiration does not. b. Energy Yield: Aerobic respiration produces more ATP (approximately 36-38 ATP molecules per glucose molecule) compared to anaerobic respiration (2 ATP molecules per glucose molecule). c. End Products: The end products of aerobic respiration are carbon dioxide and water, whereas anaerobic respiration produces lactic acid or ethanol and carbon dioxide. d. Location: Aerobic respiration occurs in the mitochondria of the cell, while anaerobic respiration occurs in the cytoplasm. e. Process Duration: Aerobic respiration is a longer process compared to the relatively quick anaerobic respiration.3. Phases of Krebs Cycle Producing Carbon Dioxide and ATP: The Krebs cycle, also known as the citric acid cycle, is a part of aerobic respiration that occurs in the mitochondria. It involves several steps that lead to the production of carbon dioxide and ATP. a. Decarboxylation: This is the process where carbon dioxide is released. In the Krebs cycle, this occurs when isocitrate is converted to α-ketoglutarate, and then α-ketoglutarate is converted to succinyl-CoA. Each of these steps involves the removal of one carbon dioxide molecule. b. ATP Production: ATP in the Krebs cycle is produced during the conversion of succinyl-CoA to succinate. This step involves substrate-level phosphorylation, where a phosphate group is directly transferred to ADP to form ATP. c. Additional Note: The Krebs cycle also produces reduced coenzymes (NADH and FADH2), which are later used in the electron transport chain to produce a significant amount of ATP.