Cellular Respiration Simulations

Cellular Respiration Simulations Visually

Learn Cellular Respiration visually with interactive simulations. Understand Glycolysis, Krebs Cycle, and Electron Transport Chain through step-by-step animations and explanations.

Energy Production Mitochondria ATP Synthesis Metabolic Cycle Oxidation Electron Transport

What is Cellular Respiration?

Cellular respiration is the process by which cells break down glucose and other organic molecules to produce adenosine triphosphate (ATP), the primary energy currency of the cell. This essential metabolic pathway occurs in three main stages: glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain.

The overall equation for cellular respiration is:

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP

Cellular respiration is crucial for all life forms as it provides the energy needed for various cellular processes including muscle contraction, protein synthesis, and active transport across membranes.

Cellular Respiration Process

Three main stages of cellular respiration

Glycolysis

Breaks down glucose into two pyruvate molecules in the cytoplasm

  • Net gain of 2 ATP molecules
  • Production of 2 NADH molecules
  • Does not require oxygen (anaerobic)

Krebs Cycle

Also known as Citric Acid Cycle, occurs in mitochondrial matrix

  • Production of 2 ATP molecules
  • Generation of 6 NADH and 2 FADH2
  • Requires oxygen (aerobic)

Electron Transport Chain

Located in inner mitochondrial membrane, produces majority of ATP

  • Production of approximately 32-34 ATP molecules
  • Uses NADH and FADH2 from previous stages
  • Final electron acceptor is oxygen

Interactive Simulations

Visualize each stage of cellular respiration with step-by-step animations

Glycolysis Steps

1
Glucose Phosphorylation

Hexokinase phosphorylates glucose using ATP

2
Isomerization

Glucose-6-phosphate is converted to fructose-6-phosphate

3
Second Phosphorylation

Phosphofructokinase adds another phosphate group

4
Cleavage

Splitting of fructose-1,6-bisphosphate into two 3-carbon molecules

5
Oxidation & Phosphorylation

Glyceraldehyde-3-phosphate is oxidized and phosphorylated

6
ATP Generation

Substrate-level phosphorylation produces 2 ATP molecules

7
Further Oxidation

Another oxidation reaction producing NADH

8
Final ATP Generation

Last substrate-level phosphorylation producing 2 more ATP

9
Pyruvate Formation

Formation of two pyruvate molecules

10
End Products

2 Pyruvate + 2 ATP + 2 NADH

Krebs Cycle Steps

1
Acetyl-CoA Formation

Pyruvate is converted to acetyl-CoA before entering cycle

2
Citrate Formation

Acetyl-CoA combines with oxaloacetate to form citrate

3
Isomerization

Citrate is converted to isocitrate

4
First Oxidation

Isocitrate is oxidized to α-ketoglutarate, producing NADH

5
Second Oxidation

α-ketoglutarate is oxidized to succinyl-CoA, producing NADH

6
Substrate-Level Phosphorylation

Succinyl-CoA converted to succinate, producing GTP (ATP)

7
Third Oxidation

Succinate oxidized to fumarate, producing FADH2

8
Hydration

Fumarate hydrated to malate

9
Final Oxidation

Malate oxidized to oxaloacetate, producing NADH

10
Cycle Completion

Oxaloacetate ready to combine with new acetyl-CoA

Electron Transport Chain

1
Electron Donors

NADH and FADH2 donate electrons to Complex I and II

2
Complex I (NADH Dehydrogenase)

Transfers electrons from NADH to ubiquinone, pumping H+

3
Complex II (Succinate Dehydrogenase)

Transfers electrons from FADH2 to ubiquinone

4
Ubiquinone (Coenzyme Q)

Mobile carrier that transfers electrons to Complex III

5
Complex III (Cytochrome bc1)

Transfers electrons to cytochrome c, pumping H+

6
Cytochrome c

Mobile carrier that transfers electrons to Complex IV

7
Complex IV (Cytochrome c Oxidase)

Transfers electrons to oxygen, forming water

8
Chemiosmosis

H+ gradient drives ATP synthase to produce ATP

9
ATP Synthase

Produces approximately 3 ATP per NADH and 2 ATP per FADH2

10
ATP Yield

Total yield: ~32-34 ATP molecules per glucose molecule

Comparison with Physics Concepts

How cellular respiration relates to fundamental physics principles

Thermodynamics

Cellular respiration exemplifies the laws of thermodynamics:

  • First Law: Energy is conserved but transformed from chemical energy in glucose to ATP
  • Second Law: Entropy increases as glucose is broken down and energy is dispersed
  • Free Energy: The process is exergonic (ΔG < 0) making it spontaneous

Electron Transport

The electron transport chain demonstrates fundamental physics principles:

  • Electrochemistry: Redox reactions transfer electrons between molecules
  • Potential Difference: Proton gradient creates electrical potential across membrane
  • Electrical Circuits: Electron flow through complexes resembles current in circuits

Kinetics

Reaction rates and enzyme kinetics govern cellular respiration:

  • Activation Energy: Enzymes lower activation barriers for reactions
  • Reaction Rates: Temperature, pH, and substrate concentration affect rates
  • Catalysis: Enzymes increase reaction rates without being consumed

Diffusion & Osmosis

Passive transport mechanisms in cellular respiration:

  • Molecular Diffusion: Oxygen and carbon dioxide move across membranes
  • Facilitated Diffusion: Specific transport proteins assist molecule movement
  • Osmotic Pressure: Water balance maintained during metabolic processes

Real-World Applications

How understanding cellular respiration impacts various fields

Exercise Physiology

Understanding how muscle cells produce energy during different intensities of exercise

  • Aerobic vs anaerobic respiration during exercise
  • Lactic acid buildup and muscle fatigue
  • Oxygen debt and recovery
Medicine

Metabolic disorders and therapeutic interventions

  • Mitochondrial diseases affecting energy production
  • Cancer cell metabolism (Warburg effect)
  • Metabolic syndrome and diabetes
Agriculture

Improving crop yields through understanding plant respiration

  • Optimizing photosynthesis-respiration balance
  • Developing stress-resistant crop varieties
  • Improving storage conditions for harvested crops