Electron Transport Chain Student Worksheet - key

The Electron Transport Chain (ETC)

outputs of the Citric Acid Cycle

  • Produces:

    • 2 ATP

    • 6 NADH

    • 2 FADH2

    • 4 CO2

Location of the ETC

  • Occurs in the inner mitochondrial membrane.

  • There can be thousands of ETCs present in one mitochondrion.

Electron Carriers

  • NADH and FADH2 carry high energy electrons to the ETC.

Final Electron Acceptors

  • Electrons from NADH and FADH2 end up binding to oxygen, forming H2O.

Energy Drop (ΔG)

  • The energy drop for electrons traveling from NADH to Oxygen is about 53 kcal/mol.

Protein Complex Interaction

  • NADH interacts with: Protein Complex I

  • FADH2 interacts with: Protein Complex II.

Large Enzyme Complexes and Mobile Molecules

  • There are 4 large enzyme complexes in the ETC.

  • There are 2 small mobile molecules that link them.

Electron Carrier States

  • Each carrier is in a reduced state when it receives electrons.

  • After donating electrons, they are in an oxidized state.

Electron Movement through the ETC

  • Electrons from NADH are taken by Protein Complex I and pass through a series of complexes until accepted by oxygen.

  • The electronegativity of the protein complexes increases, with Complex IV being the most electronegative.

Energy Utilization

  • As electrons move through protein complexes, their energy permits H+ ions to be pumped from the matrix to the intermembrane space.

H+ Ion Concentration and ATP Formation

H+ Concentration Comparison

  • Higher concentration of H+ in the intermembrane space compared to the mitochondrial matrix.

Movement of H+ Ions

  • H+ ions return to the mitochondrial matrix through the protein ATP synthase.

ATP Generation from ETC

  • Chemiosmosis: H+ ions flowing through ATP synthase spin a rotor, binding a phosphate onto ADP to generate ATP.

ATP synthesis from carriers

  • Each NADH synthesizes: 2.5 ATP

  • Each FADH2 synthesizes: 1.5 ATP

Total NADH and ATP Calculation

  • NADH from previous steps: 10 NADH provide:

    • 10 x 2.5 = 25 ATP from NADH

  • FADH2 from previous steps: 2 FADH2 provide:

    • 2 x 1.5 = 3 ATP from FADH2

Total ATP Production Under Ideal Conditions

  • Glycolysis: 2 ATP

  • Pyruvate Oxidation: 0 ATP

  • Citric Acid Cycle: 2 ATP

  • ETC: 28 ATP

  • Total ATP Produced: 32 ATP

Energy Transfer Calculation

  • Energy released from one mole of glucose: 686 kcal.

  • Energy stored in one mole of ATP: 7.3 kcal.

  • % of potential energy transferred to ATP: 34%.

Structure of Mitochondria and Function

  • Structure includes: outer membrane, inner membrane, intermembrane space, mitochondrial matrix.

  • Discuss reactions occurring in/across each component to illustrate the functional design of mitochondria.