Cellular Respiration and Redox Reactions Flashcards

Vocabulary flashcards covering Redox Reactions, Glycolysis, Pyruvate Oxidation, Krebs Cycle, Electron Transport Chain, and Chemiosmosis based on lecture notes.

Oxidation

The chemical process of losing one or more electrons.

Reduction

The chemical process of gaining one or more electrons, which reduces the overall charge of the molecule.

Redox Reaction

An oxidation-reduction reaction that transfers electrons ($e^-$) between molecules, where oxidation and reduction always occur simultaneously.

LEO says GER

A mnemonic device for redox reactions standing for: Lose Electrons Oxidation, Gain Electrons Reduction.

Electron Carriers

Molecules such as $NADH$ and $FADH_2$ that carry two high-energy electrons to shuttle them to different locations within a cell like an electron taxi cab.

Aerobic Cellular Respiration

The process of breaking down glucose in the presence of oxygen gas ($O_2$) to produce $30\text{-}38$ $ATP$ molecules, releasing $CO_2$ and $H_2O$ as by-products.

Glycolysis

The 1st step of cellular respiration occurring in the cytoplasm without oxygen, which converts one 6-carbon glucose molecule into two 3-carbon pyruvate molecules, netting $2$ $ATP$ and $2$ $NADH$.

Energy Investment Phase

The initial phase of glycolysis that requires an investment of $2$ $ATP$ molecules to initiate glucose breakdown.

Pyruvate Oxidation

The process in the mitochondrial matrix that converts each pyruvate molecule into Acetyl-CoA, releasing $2$ $CO_2$ and producing $2$ $NADH$ per glucose molecule.

Krebs Cycle

Also known as the Citric Acid Cycle; a sequence of reactions in the mitochondrial matrix that oxidizes Acetyl-CoA to yield $2$ $ATP$, $6$ $NADH$, $2$ $FADH_2$, and $4$ $CO_2$ per glucose molecule across two turns.

Oxaloacetate

A 4-carbon molecule in the Krebs cycle that combines with Acetyl-CoA to form citric acid and is regenerated at the end of each cycle.

Electron Transport Chain (ETC)

The 3rd step of aerobic respiration consisting of inner mitochondrial membrane proteins that harness electron energy from $NADH$ and $FADH_2$ to pump $H^+$ ions into the intermembrane space.

Final Electron Acceptor

Oxygen gas ($O_2$), which accepts the final electrons at the end of the electron transport chain and reacts with $H^+$ ions to form water ($H_2O$).

Chemiosmosis

The diffusion of $H^+$ ions across the inner mitochondrial membrane down their concentration gradient through ATP Synthase to generate $ATP$.

ATP Synthase

The membrane enzyme that facilitates chemiosmosis and synthesizes $ATP$ as $H^+$ ions pass through it.

Oxidative Phosphorylation

The combined process of the Electron Transport Chain and Chemiosmosis that synthesizes a large amount of $ATP$ using redox energy.

Substrate-Level Phosphorylation

A type of phosphorylation that synthesizes $ATP$ using an enzyme to directly transfer a phosphate group from a substrate to ADP, occurring during Glycolysis and the Krebs Cycle.