Unit 6 Study Guide PDF

6.1 Glycolysis Purpose: To break down glucose into two molecules of pyruvate, generating ATP and NADH. Location: Cytoplasm. Phases: ○ Energy Investment Phase: 2 ATP molecules are consumed. ○ Energy Payoff Phase: 4 ATP molecules and 2 NADH are produced....

6.1 Glycolysis Purpose: To break down glucose into two molecules of pyruvate, generating ATP and NADH. Location: Cytoplasm. Phases: ○ Energy Investment Phase: 2 ATP molecules are consumed. ○ Energy Payoff Phase: 4 ATP molecules and 2 NADH are produced. Major Products: ○ 2 Pyruvate ○ 2 NADH ○ Net gain of 2 ATP 6.2 Fermentation Mechanism: ○ Occurs when oxygen is not available. ○ Regenerates NAD⁺ from NADH to allow glycolysis to continue. ○ Produces lactate (in animals) or ethanol and CO₂ (in yeast/plants). Purpose: Ensures ATP production via glycolysis in anaerobic conditions. 6.3 Krebs Cycle (Citric Acid Cycle) – Detailed Overview Purpose The Krebs Cycle oxidizes acetyl-CoA to CO₂, generating NADH and FADH₂, which carry high-energy electrons to the Electron Transport Chain (ETC). Location Mitochondrial matrix. Key Molecules Involved Reactants/Inputs: ○ Acetyl-CoA (from pyruvate oxidation) ○ NAD⁺ (electron carrier) ○ FAD (electron carrier) ○ ADP + Pi Products/Outputs:  ○ 3 NADH (per acetyl-CoA) ○ 1 FADH₂ (per acetyl-CoA) ○ 1 ATP (via substrate-level phosphorylation) ○ 2 CO₂ Key Points Per Acetyl-CoA (1 Cycle): ○ 3 NADH, 1 FADH₂, 1 ATP, and 2 CO₂ are produced. Per Glucose Molecule (2 Acetyl-CoA) (2 turns half of everything for one turn) ○ 6 NADH, 2 FADH₂, 2 ATP, and 4 CO₂ are produced. NADH and FADH₂ are crucial for transferring high-energy electrons to the ETC, where most ATP is generated. By breaking down acetyl-CoA into CO₂, the cycle maximizes energy capture in the form of reduced electron carriers (NADH and FADH₂) while preparing these carriers for their role in oxidative phosphorylation. 6.4 Electron Transport Chain (ETC) and Oxidative Phosphorylation Purpose: Use electrons from NADH and FADH₂ to create a proton gradient, driving ATP synthesis. Location: Inner mitochondrial membrane. Energy and Molecule Flow: ○ Electrons move through protein complexes (I-IV). ○ Protons are pumped into the intermembrane space, creating a gradient. ○ ATP synthase uses the gradient to convert ADP + Pi into ATP. ○ Oxygen acts as the final electron acceptor, forming water. 6.5 Comparison of Photosynthesis and Cellular Respiration Photosynthesis: Converts light energy into chemical energy (glucose). ○ Location: Chloroplasts. ○ Key Processes: Light-dependent reactions and Calvin Cycle. Cellular Respiration: Converts glucose into usable energy (ATP). ○ Location: Mitochondria. ○ Key Processes: Glycolysis, Krebs Cycle, ETC. Similarities: Both involve energy transformations and electron carriers. Differences:  ○ Photosynthesis stores energy; respiration releases it. ○ Opposite reactants and products: Photosynthesis: CO₂ + H₂O → Glucose + O₂ Respiration: Glucose + O₂ → CO₂ + H₂O 6.6 Internal and External Factors Affecting Rates Photosynthesis: ○ Internal: Chlorophyll concentration, enzyme activity. ○ External: Light intensity, CO₂ concentration, temperature. Cellular Respiration: ○ Internal: Enzyme levels, substrate availability. ○ External: Oxygen levels, temperature. Predictions: ○ High light/CO₂ increases photosynthesis. ○ Low oxygen inhibits aerobic respiration. ○ Extreme temperatures disrupt enzyme function in both processes.