Aerobic vs. Anaerobic Respiration (1)

Aerobic vs Anaerobic Respiration

  • Aerobic Respiration: Process that requires oxygen to produce energy.

  • Anaerobic Respiration: Process that occurs without oxygen.

The Mitochondria

  • Each mitochondrion consists of:

    • Outer membrane: Composed of lipids, separates the mitochondrion from the cytoplasm.

    • Inner membrane: Site of the electron transport chain (ETC).

    • Cristae: Infoldings of the inner membrane that increase surface area for ATP production.

    • Matrix: Space within the inner membrane where the Krebs Cycle takes place.

Mitochondrial Structure

  • Inner Membrane: Contains electron transport proteins.

  • Outer Membrane: Semi-permeable, allowing specific molecules to pass.

  • Intermembrane Space: Area between the inner and outer membranes.

  • Cristae: Provide increased surface area for the processes of respiration.

  • Matrix: Contains enzymes for the Krebs Cycle and mitochondrial DNA.

Krebs Cycle

  • Glycolysis starts the energy extraction from glucose; if oxygen is present, the Krebs Cycle continues the process.

  • Process Overview:

    • Pyruvate is converted into Acetyl-CoA in the mitochondrial matrix.

    • During the cycle, CO2 is released.

  • Outputs per Glucose:

    • 6 CO2

    • 8 NADH

    • 2 FADH2

    • 2 ATP

Krebs Cycle Detail

  • Key Components:

    • Pyruvic acid

    • Acetyl-CoA formation

    • OAA (Oxaloacetate) combines with Acetyl-CoA to form citric acid (Citrate).

    • Cycle includes several redox reactions that yield NADH and FADH2.

Electron Transport Chain (ETC)

  • Function: Utilizes energy carried by NADH and FADH2 to produce ATP.

  • Process:

    • Electrons are transported down the chain, releasing energy used to pump H+ ions into the intermembrane space.

    • Oxygen serves as the final electron acceptor, forming water (H2O).

  • Outputs per Glucose:

    • 32 ATP produced

    • 6 H2O generated

Alternate Food Pathways

  • Organisms can utilize:

    • Proteins: Broken down into amino acids.

    • Carbohydrates: Converted into glucose for glycolysis.

    • Lipids: Broken down into glycerol and fatty acids.

  • Pathways involved:

    • Glycolysis

    • Krebs Cycle

    • Electron transport chain

Fermentation

  • Definition: Anaerobic process to extract energy from glucose without oxygen.

    • Does not produce additional ATP beyond glycolysis.

Lactic Acid Fermentation

  • Process converting glucose into lactic acid.

    • Produces 2 Lactate and regenerates 2 NAD+ from NADH.

Alcohol Fermentation

  • Process converting glucose into ethanol and CO2.

    • Involves the conversion of pyruvate to acetaldehyde, followed by conversion to ethanol.

Mechanics of Fermentation

  • Yeast Fermentation: Produces ethanol and CO2.

  • Muscle Fermentation: Produces lactate.

    • Glucose → 2 Pyruvate → 2 ATP (net yield)

Fermentation Products

  • Various products include:

    • Ethanol (Beer, Wine)

    • Lactic acid (Yogurt, Cheese)

    • Acetic acid (Vinegar)

  • Applications in everyday products.

Benefits of Fermentation

  • Food Production: Creates consumable food and beverages.

  • Health Benefits: Produces probiotics that aid in digestion.

  • Energy Supply: Offers short-term energy when oxygen is limited.

  • Physiological Signals: Lactic acid accumulation indicates need for rest.

Videos

  • Topics Covered:

    • Aerobic Respiration

    • Anaerobic Respiration: Fermentation

    • Cellular Respiration Song