MCB 150 Lecture 11: Cellular Respiration

Flashcards for MCB 150 Lecture 11 on Cellular Respiration, focusing on key vocabulary and concepts.

Phase 2 of Cellular Respiration:

Oxidation of Pyruvate and the Krebs Cycle

Oxygen

Aerobic respiration requires this, but the Krebs Cycle itself does not directly.

Electron Transport Chain (ETC)

The pathway coupled to Krebs Cycle that requires oxygen.

Oxidative Phosphorylation

The process involving the Electron Transport Chain and chemiosmosis to produce ATP.

NADH

Molecule that donates electrons to the first carrier in the Electron Transport Chain, being re-oxidized to NAD+.

Proton Gradient (Electrochemical Gradient)

Generated when energy is used to pump protons across the membrane in the electron transport chain.

Oxygen

Accepts electrons from the last electron carrier in the ETC, combining with protons to form water.

FADH2

Molecule which also joins the electron transport chain, bypassing Complex I resulting in fewer protons pumped.

Result of Electron Transport Chain

Regenerated cofactors and a built gradient, but no ATP directly.

Proton Gradient

The gradient that is unstable, driving protons back into the mitochondrial matrix.

36 ATP

The theoretical ATP production from the full oxidation of one glucose molecule.

Phase 2 of Cellular Respiration:

Oxidation of Pyruvate and the Krebs Cycle

Oxygen

Aerobic respiration requires this, but the Krebs Cycle itself does not directly.

Electron Transport Chain (ETC)

The pathway coupled to Krebs Cycle that requires oxygen.

Oxidative Phosphorylation

The process involving the Electron Transport Chain and chemiosmosis to produce ATP.

NADH

Molecule that donates electrons to the first carrier in the Electron Transport Chain, being re-oxidized to NAD+.

Proton Gradient (Electrochemical Gradient)

Generated when energy is used to pump protons across the membrane in the electron transport chain.

Oxygen

Accepts electrons from the last electron carrier in the ETC, combining with protons to form water.

FADH2

Molecule which also joins the electron transport chain, bypassing Complex I resulting in fewer protons pumped.

Result of Electron Transport Chain

Regenerated cofactors and a built gradient, but no ATP directly.

Proton Gradient

The gradient that is unstable, driving protons back into the mitochondrial matrix.

36 ATP

The theoretical ATP production from the full oxidation of one glucose molecule.

ATP Synthase

The enzyme that harnesses the proton gradient to produce ATP through chemiosmosis.

Chemiosmosis

The process where energy stored in a proton gradient is used to synthesize ATP.

Complex I

The first protein complex in the electron transport chain, which accepts electrons from NADH.

Complex II

Receives electrons from FADH2, bypassing Complex I and contributing fewer protons to the gradient.

Coenzyme Q (Ubiquinone)

A mobile electron carrier that transfers electrons from Complex I and Complex II to Complex III.

Cytochrome c

Another mobile electron carrier that transfers electrons from Complex III to Complex IV.

Complex III

Accepts electrons from Coenzyme Q and pumps protons across the inner mitochondrial membrane.

Complex IV

Transfers electrons to oxygen, reducing it to water, and also pumps protons.