5 WK 5 Carbon Cycling_ CR 24-25 Andrew Nguyen_ Cellular Respiration

Cellular Respiration Overview

• Definition: The process that releases energy from food through oxidation of glucose.

• Types of Respiration:

  • Aerobic: Requires oxygen.

  • Anaerobic: Occurs without oxygen.

• Chemical Equation for Aerobic Respiration:

  • C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

  • Glucose + Oxygen → Carbon dioxide + Water + Energy

Cellular Respiration Process Summary

• Key molecules:

  • Reactive molecules and carriers such as NADH.

• Steps Involved:

  1. Glycolysis:

     • Converts glucose into pyruvate.

     • Produces 2 ATP.

  2. Citric Acid Cycle (Krebs Cycle):

     • Produces NADH and ATP.

  3. Electron Transport Chain:

     • Produces 32 ATP using oxygen.

Comparison of Respiration Types

• Anaerobic Respiration:

  • Simple and short-term process.

  • Produces little ATP.

• Aerobic Respiration:

  • Complex, multi-step process.

  • Produces lots of ATP.

Anaerobic Respiration Mechanism

• Glycolysis: Occurs in the cytoplasm. Produces:

  • 2 NADH

  • 2 ATP

  • 2 pyruvic acids.

• Types of Anaerobic Fermentation:

  • Alcoholic Fermentation: Produces ethanol and CO2.

  • Lactic Acid Fermentation: Produces lactic acid.

Organisms Involved in Anaerobic Respiration

• Common Organisms:

  • Yeast (Saccharomyces),

  • Lactic acid bacteria (Lactobacillus),

  • Clostridium (produces acetone, isopropanol).

Stages of Cellular Respiration

• Three Stages:

  1. Glycolysis (in cytoplasm):

     • Breaks down glucose to pyruvate.

  2. Krebs Cycle (in mitochondrial matrix):

     • Processes acetyl CoA, generating NADH and ATP.

  3. Electron Transport Chain (in inner mitochondrial membrane):

     • NADH and FADH2 drop electrons, producing ATP via oxidative phosphorylation.

Electron Transport Chain Details

• Process:

  • Electrons from NADH and FADH2 pass through a series of proteins, release energy that is used to pump H+ into the intermembrane space, leading to ATP production.

• Final Products:

  • Water formed as electrons combine with oxygen and hydrogen ions.

ATP Production Summary

• Total ATP Yield:

  • From glucose: approximately 30 to 32 ATP.

  • Breakdown: 2 from glycolysis, 2 from Krebs cycle, and 26 to 28 from oxidative phosphorylation.

Cellular Work Fueled by ATP

• Types of Work:

  • Active transport, muscle contraction, biosynthesis, etc.

Comparison: Cellular Respiration vs. Photosynthesis

• Similarities: Both involve energy transfer processes in cells, involve electron transport.

• Differences: Location (mitochondria vs chloroplast), reactants/products.

Summary Graphics

• Diagrams and models illustrating glycolysis, the Krebs cycle, and the light-independent reactions (Calvin Cycle).

Notes on Glycolysis and Calvin Cycle

• Glycolysis Product: Converts glucose to pyruvate and produces ATP via substrate-level phosphorylation.

• The Calvin Cycle converts CO2 into glucose utilizing ATP and NADPH, connecting respiration and photosynthesis metabolic pathways.