Cellular Respiration Vocabulary

Vocabulary flashcards covering the key terms, stages, molecules, and mechanisms of cellular respiration.

Cellular Respiration

The process organisms use to convert chemical energy stored in the bonds of glucose into usable chemical energy in ATP.

Aerobic Respiration

A form of respiration that requires oxygen to occur in cells, producing ATP to maintain homeostasis.

Anaerobic Respiration (Fermentation)

Respiration that occurs without oxygen, breaking down ATP to oxidize NADH back into $NAD^+$ to keep glycolysis going.

Glycolysis

A set of anaerobic chemical reactions in the cytoplasm that oxidizes glucose into two pyruvate molecules, producing a net gain of $2\text{ ATP}$ and $2\text{ NADH}$.

Pyruvate

The three-carbon precursor molecule generated by glycolysis that serves as the starting point for both aerobic and anaerobic respiration.

Pyruvate Oxidation (Link Reaction)

The step where pyruvate is converted into acetyl-CoA as it moves from the cytoplasm into the mitochondrial matrix.

Acetyl-CoA

A molecule formed from pyruvate oxidation that enters the Citric Acid Cycle.

Citric Acid Cycle (Krebs Cycle)

A series of exergonic reactions in the mitochondrial matrix that processes acetyl-CoA, releasing $CO_2$ and reducing $NAD^+$ and FAD to NADH and $FADH_2$.

Mitochondrial Matrix

The innermost compartment of the mitochondrion containing enzymes and a suitable pH for the Citric Acid Cycle.

Electron Carriers ($NAD^+$ / NADH & FAD / $FADH_2$)

Molecules that shuttle high-energy electrons from earlier metabolic steps to the electron transport chain.

Electron Transport Chain (ETC)

A sequence of protein complexes on the inner mitochondrial membrane that transfers electrons, releasing energy used to pump $H^+$ ions across the membrane.

Oxidative Phosphorylation

The production of ATP using energy derived from the redox reactions of the electron transport chain.

Chemiosmosis

The movement of $H^+$ ions diffusing down their electrochemical gradient through ATP synthase, which powers the phosphorylation of ADP to ATP.

ATP Synthase

An enzyme in the inner mitochondrial membrane that utilizes the kinetic energy of flowing $H^+$ ions to synthesize ATP from ADP and inorganic phosphate.

Electrochemical Gradient

The combined gradient of proton concentration ($H^+$) and electrical charge across the inner mitochondrial membrane. It serves as the stored potential energy that drives protons through ATP synthase during chemiosmosis to produce ATP.