Definition: Cellular respiration is the process by which cells convert sugar and oxygen into energy (ATP), carbon dioxide, and water. It is a crucial metabolic pathway necessary for all forms of life.
Understand energy and redox reactions.
Compare reactants, products, and energy yield of the three stages of cellular respiration:
Glycolysis
Pyruvate Processing
Citric Acid Cycle
Electron Transport Chain
Analyze relationship between electron transport chain and oxidative phosphorylation.
Importance of oxygen in cellular respiration.
Structure of mitochondria and its functional significance.
Differentiate between cellular respiration and fermentation regarding inputs, outputs, and ATP production.
Role of Energy: All life requires energy, which is obtained through cellular respiration.
Photosynthesis and Cellular Respiration:
Plants convert sunlight energy into chemical energy (sugars) through photosynthesis.
Both plants and animals utilize cellular respiration to convert sugars into ATP.
Respiration Equation:
Formula: 6CO2 + 6H2O + energy ↔ C6H12O6 + 6O2 (indicating the conversion of glucose and oxygen to carbon dioxide and water while producing energy).
Kinetic Energy: Energy of motion, e.g., thermal energy from moving molecules (heat).
Potential Energy: Stored energy in chemical bonds or concentration gradients.
Energy Transformations: Energy is transformed from one type to another during biochemical processes.
First Law of Thermodynamics: Energy cannot be created or destroyed, only transformed.
Exothermic Reactions: Release energy; products have less potential energy than reactants.
Endothermic Reactions: Absorb energy; products have higher potential energy than reactants.
Catabolic Pathways: Break down molecules to release energy (exothermic), primarily for ATP production.
Anabolic Pathways: Use ATP to synthesize larger molecules from smaller components (endothermic).
Enzymatic Functions: Enzymes direct metabolic reactions, facilitating cells' acquisition and use of energy.
Metabolic Pathways: Series of enzyme-catalyzed reactions breaking down or building up biomolecules.
Definition: Process of harvesting chemical energy from organic molecules resulting in the generation of ATP.
Aerobic Process: Requires oxygen for effective energy yield.
Gas Exchange: Cells intake oxygen (O2) and release carbon dioxide (CO2) as waste.
Glycolysis:
Occurs in cytoplasm.
Converts glucose to two pyruvate molecules, yielding 2 ATP and 2 NADH.
Pyruvate Processing:
Pyruvate is oxidized to form Acetyl CoA, producing CO2 and NADH.
Citric Acid Cycle:
Acetyl CoA is oxidized to CO2, resulting in NADH, FADH2, and ATP from substrate-level phosphorylation.
Electron Transport Chain and Oxidative Phosphorylation:
Electrons from NADH and FADH2 are transferred through the chain to form a proton gradient that drives ATP synthesis.
ATP Structure and Function: Essential for driving cellular processes; energy is released when phosphate bonds are broken during hydrolysis.
Role of Electron Carriers: NAD+ and FAD accept electrons during glycolysis and the citric acid cycle, becoming NADH and FADH2.
Redox Reactions: Involve electron transfers; oxidation (loss of electrons) and reduction (gain of electrons) occur together.
Feedback Inhibition: High ATP levels inhibit glycolysis and pyruvate processing pathways to prevent excess energy production.
Acetyl CoA contributes to CO2 production, energy carrier accumulation (NADH, FADH2), and ATP synthesis.
Complete glucose oxidation yields CO2, ATP, NADH, and FADH2. Total yield is approximately 29 ATP per glucose molecule.
Definition: Anaerobic process when oxygen is absent; regenerates NAD+ for glycolysis.
Types of Fermentation:
Lactic Acid Fermentation: Occurs in muscle cells, producing lactate and reopening NAD+.
Alcohol Fermentation: Involves yeast and generates ethanol and CO2.
Efficiency: Fermentation is less efficient than cellular respiration, generating only 2 ATP per glucose compared to respiration's 29 ATP.