University:
University of Ottawa
Course:
BIO 1130 | Introduction to Organismal Biology
Academic year:

2024
Views:

468

Pages:

3
Author:

xxzakxx 45

Cellular Respiration: The Powerhouse of Life Introduction Cellular respiration, where cells transform energy from nutrients into ATP (adenosine triphosphate) - the main energy unit for cells, is a basic process. Every living creature needs this to happen because it helps them carry out various activities within their cells such as protein creation and muscle movement. Types of Cellular Respiration Aerobic Respiration: Requires oxygen and is the most efficient form of cellular respiration. Anaerobic respiration: This process does not need oxygen and is less effective. It involves methods such as fermentation. Stages of Aerobic Cellular Respiration Glycolysis: Location: Cytoplasm Input: Glucose (6-carbon sugar) Output: 2 Pyruvate molecules (3-carbon), 2 ATP, 2 NADH Glucose is changed into pyruvate, and a small number of ATP and NADH are made. Pyruvate Oxidation (Link Reaction): Location: Mitochondrial matrix Input: 2 Pyruvate molecules Output: 2 Acetyl-CoA molecules, 2 NADH, 2 CO2 Key Points: Pyruvate is converted to Acetyl-CoA, releasing carbon dioxide and producing more NADH. Krebs Cycle (Citric Acid Cycle): Location: Mitochondrial matrix Input: 2 Acetyl-CoA molecules Output: 6 NADH, 2 FADH2, 2 ATP, 4 CO2 Acetyl-CoA, which is produced in the previous steps, undergoes more breakdown. This creates extra NADH, FADH2 and ATP while freeing carbon dioxide. Oxidative Phosphorylation (Electron Transport Chain and Chemiosmosis): Location: Inner mitochondrial membrane Input: NADH, FADH2, O2 Output: ATP (32-34), H2O NADH and FADH2 give their electrons to the ETC, resulting in a proton gradient. This gradient is what causes ATP synthesis via chemiosmosis. Oxygen serves as the ultimate receiver of electrons, forming water. Energy Yield Theoretical maximum yield: 38 ATP per glucose molecule Actual yield: ~30-32 ATP per glucose molecule (due to energy losses) Anaerobic Respiration Fermentation: It is a metabolic process where sugar changes into acids, gases or alcohol when there's no oxygen. Types: Lactic Acid Fermentation: Occurs in muscle cells and some bacteria. Produces lactic acid. Alcoholic Fermentation: Occurs in yeast and some bacteria. Produces ethanol and carbon dioxide. Importance of Cellular Respiration Provides energy for all cellular activities. Allows organisms to use a variety of energy sources (carbohydrates, fats, proteins). Plays a crucial role in carbon and oxygen cycles. Additional Notes Mitochondria: The organelles where most of cellular respiration takes place in eukaryotes. Enzymes: Biological catalysts that facilitate the reactions of cellular respiration. Coenzymes: Molecules that assist enzymes in their functions. Redox Reactions: Reduction-oxidation reactions that involve the transfer of electrons.