Photosynthesis + Cellular Respiration

• Photosynthesis is the process of converting light energy, carbon dioxide, and water into glucose and oxygen
• Photosynthesis equation: 6CO2 + 6H2O → C6H12O6 + 6O2
• During photosynthesis, water is split to provide hydrogen which combines with carbon dioxide to produce glucose and releases oxygen as a by-product.
• Photosynthesis includes 'carbon fixing' because carbon atoms from the air are incorporated into organic molecules
• Chloroplasts are double membrane-bound organelles found in plants and algae that contain flat, fluid-filled sacs (thylakoids) where photosynthesis occurs
• Chlorophyll, a green pigment found in the thylakoids of chloroplasts, is responsible for absorbing light energy used in photosynthesis
• Chlorophylls are located on the grana membranes of chloroplasts, while the stroma membranes surround the fluid-filled space (the stroma) between the grana
• The thylakoids are the inner membranes that make up both the granal and stromal areas in chloroplasts
• Photosynthesis occurs in two stages: Light Dependent Stage (water splitting) and Light Independent Stage (carbon fixing)
• Light Dependent Stage occurs on the grana of a chloroplast where light energy is used to split water into hydrogen and oxygen
• Light Independent Stage occurs in the stroma of a chloroplast and does not need light to combine hydrogen with carbon dioxide to form glucose
• Chemosynthetic autotrophs oxidize chemical substances like sulphides into sulphates to create ATP and build glucose molecules with available CO2 and water
• Endosymbiosis theory proposes that mitochondria and chloroplasts were once small bacteria engulfed by larger cells, leading to the evolution of multicellular eukaryotes from single-celled prokaryotes
• Cellular respiration is the process by which cells convert glucose into ATP energy, releasing stored energy for metabolic processes
• Aerobic cellular respiration oxidizes glucose to produce carbon dioxide and water, releasing energy to produce ATP
• Anaerobic cellular respiration occurs without oxygen, splitting glucose into pyruvate to produce 2 ATP molecules
• Anaerobic cellular respiration in yeast, plants, and bacteria breaks down pyruvate into ethanol and carbon dioxide, as in bread making and alcohol brewing
• Anaerobic cellular respiration in mammals breaks down pyruvate into lactic acid after oxygen reserves are depleted, causing muscle fatigue
• Glycolysis, Krebs Cycle, and Electron Transport Chain are stages of aerobic cellular respiration that occur in the cytosol, matrix of mitochondria, and cristae of mitochondria, respectively
• Aerobic cellular respiration produces 30-32 ATP molecules through these stages
• Anaerobic cellular respiration only produces 2 ATP molecules from glycolysis
• Anaerobic cellular respiration in mammals can only be maintained for approximately 60 seconds before lactic acid buildup causes muscle fatigue