Recording-2025-02-11T01:56:27.201Z

Summer Metabolism Overview

• Covers four main topics:

  • Photosynthesis

  • Glycolysis

  • Fermentation

  • Cellular Respiration

• Importance of understanding connections between these processes.

Photosynthesis

• Essential for converting light into chemical energy.

• Key Points to Remember:

  • Photosynthesis Equation:

    • Equation: 6 CO₂ + 6 H₂O + light energy → C₆H₁₂O₆ + 6 O₂

  • Three Major Components:

    • Carbon dioxide

    • Water

    • Light energy

  • Outcomes:

    • Glucose (sugar) for energy storage

    • Oxygen released into the atmosphere

• Leaf Structure:

  • Main component: Chloroplasts

  • Contains two primary areas:

    • Thylakoids (Solenoid): Site of light reactions

      • Light energy splits water, releasing oxygen, forming ATP and NADPH

    • Stroma: Site of carbon cycle reactions

Light Reactions

• Occur in the thylakoid membranes.

• Key Inputs:

  • Light

  • Water

• Key Outputs:

  • Oxygen (released)

  • ATP and NADPH (energy carriers)

• Electron Transport Chain:

  • Electrons from water splitting enter chain, creating a proton gradient

  • ATP synthesized through chemiosmosis via ATP synthase

  • Definition of Chemiosmosis: Movement of hydrogen ions down a gradient to produce ATP.

Carbon Cycle (Calvin Cycle)

• Four Major Steps:

  1. Carbon fixation

  2. Reduction phase (producing G3P)

  3. Regeneration of ribulose bisphosphate (RuBP)

  4. Synthesis of sugar, primarily glucose

• Requires multiple cycles to form one sugar.

Pigments in Photosynthesis

• Main Pigments:

  • Chlorophyll a: Absorbs red/blue light

  • Chlorophyll b: Assists absorption across wavelengths

  • Carotenoids: Absorb blue/green light and reflect orange/red

• These pigments are crucial for capturing light energy.

Glycolysis

• Definition: Breakdown of glucose (a monosaccharide) into pyruvate.

• Occurs in the cytoplasm of all cells (prokaryotic and eukaryotic).

• Stages of Glycolysis:

  1. Energy Investment Phase:

     • 2 ATP molecules are used

     • Glucose → Fructose-1,6-bisphosphate

  2. Energy Harvesting Phase:

     • Produces 4 ATP (net gain of 2 ATP) and 2 NADH.

• Total Products from Glycolysis per Glucose:

  • 2 Pyruvate

  • 2 ATP (net)

  • 2 NADH

Cellular Respiration

• Four Main Stages:

  1. Glycolysis

  2. Pyruvate oxidation (acetyl CoA formation)

  3. Krebs Cycle (Citric Acid Cycle)

  4. Electron Transport Chain and Chemiosmosis

• Mitochondrial Structure:

  • Double membrane with a matrix and intermembrane space

  • Acetyl CoA enters Krebs cycle after glycolysis.

• Krebs Cycle Outputs: per glucose

  • 2 ATP

  • 8 NADH

  • 2 FADH₂

  • 6 CO₂ released

• Electron Transport Chain:

  • High-energy electrons used to pump protons, creating ATP via ATP synthase

  • Oxygen acts as the terminal electron acceptor, forming water

• Total ATP Produced in Cellular Respiration: Approximately 32-36 ATP from one glucose molecule.

Conclusion

• Understanding these metabolic processes is crucial for studying energy transfers in living organisms, emphasizing the importance of photosynthesis and respiration in the ecosystem.