Bioenergetics

• Photosynthesis Equation


  6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2
• Photosynthesis


  A process by which plants convert light energy from the sun into chemical energy in the form of glucose (sugar)
• Glucose


  A type of sugar produced during photosynthesis
• Carbon Dioxide (CO2)


  A molecule used in the photosynthetic reaction
• Water (H2O)


  A molecule used in the photosynthetic reaction
• Oxygen (O2)


  A byproduct of photosynthesis released into the atmosphere
• Light Energy


  Energy from the sun used to power photosynthesis
• Light-Dependent Reactions


  Occur in the thylakoid membranes of the chloroplast, involve absorption of light energy by pigments, produce ATP and NADPH
• Light-Independent Reactions (Calvin Cycle)


  Occur in the stroma of the chloroplast, use ATP and NADPH produced in light-dependent reactions, incorporate CO2 into glucose, produce glucose and O2 as byproducts
• Thylakoid Membranes


  Where light-dependent reactions take place in the chloroplast
• Pigments


  Substances that absorb light energy in the light-dependent reactions (such as chlorophyll)
• ATP


  Adenosine Triphosphate, produced in light-dependent reactions and used in light-independent reactions
• Chlorophyll

  A pigment responsible for absorbing light energy in photosynthesis, absorbing light in the blue and red parts of the visible spectrum and passing energy to other molecules
• Light Absorption

  Chlorophyll absorbs light energy in the blue and red parts of the visible spectrum (400-450 nm and 650-700 nm)
• Energy Transfer


  Chlorophyll passes energy to other molecules, which convert it to ATP and NADPH in the light-dependent reactions
• Light Intensity


  Increase in light intensity increases the rate of photosynthesis, but excessive light can be harmful
• Temperature


  Optimal temperature for photosynthesis is around 20-30°C, but high or low temperatures can affect photosynthesis
• Water


  Adequate water supply is necessary for photosynthesis, as it is used in the production of ATP and NADPH
• Carbon Dioxide


  Increase in CO2 concentrations can increase the rate of photosynthesis, as CO2 is used in the Calvin cycle
• Oxygen


  High oxygen concentrations can inhibit photosynthesis by competing with CO2 for binding sites on the enzyme RuBisCO
• Salinity


  High salt concentrations can inhibit photosynthesis by disrupting the structure and function of the thylakoid membranes
• Air Pollutants


  Air pollutants such as SO2, NO2, and O3 can inhibit photosynthesis by interacting with the photosynthetic apparatus
• Glycolysis


  Process by which glucose is converted into pyruvate in the cytosol of the cell through a series of enzyme-catalyzed reactions
• Pyruvate


  Intermediate product of glycolysis, converted into acetyl-CoA, which is then fed into the citric acid cycle (Krebs cycle)
• Citric Acid Cycle


  Process by which acetyl-CoA is converted into ATP, NADH, and FADH2 in the mitochondria
• Electron Transport Chain


  Process by which NADH and FADH2 are used to generate ATP through chemiosmosis in the mitochondrial inner membrane
• ATP Synthesis


  Process by which the energy from NADH and FADH2 is used to pump protons across the mitochondrial inner membrane, creating a proton gradient that drives the production of ATP
• Energy Production


  Respiration is the primary mechanism by which cells generate energy from glucose
• ATP Production


  Respiration produces ATP, which is the primary energy currency of the cell
• Maintenance of Cellular Functions


  Energy generated by respiration is necessary for the maintenance of cellular functions, such as protein synthesis, membrane transport, and muscle contraction
• Regulation of Metabolic Pathways


  Respiration helps regulate other metabolic pathways, such as glycolysis and the citric acid cycle, by providing feedback mechanisms
• Balance of pH


  Respiration helps maintain pH balance by producing bicarbonate ions, which help buffer excess hydrogen ions
• Regulation of Blood Pressure


  Respiration helps regulate blood pressure by adjusting the amount of ATP generated
• Warmth Generation


  Respiration produces heat as a byproduct, which helps maintain body temperature
• Pyruvate Conversion


  Pyruvate is converted into acetyl-CoA in the mitochondria during aerobic respiration
• Citric Acid Cycle


  Pathway in which acetyl-CoA is converted into ATP, NADH, and FADH2 during aerobic respiration
• Electron Transport Chain


  Pathway in which NADH and FADH2 are passed through to generate ATP during aerobic respiration
• Oxygen's Role


  Oxygen reacts with high-energy electrons from the electron transport chain to produce water and carbon dioxide during aerobic respiration
• ATP Synthesis


  Process by which electrons are used to produce ATP through chemiosmosis during aerobic respiration
• Pyruvate Conversion


  Pyruvate is converted into lactic acid (in muscle cells) or ethanol (in yeast cells) without oxygen during anaerobic respiration