Aerobic Respiration and Mitochondrial Structure

Vocabulary practice flashcards covering the stages of aerobic respiration, mitochondrial anatomy, and chemical reactants, intermediates, and products.

Aerobic respiration

The process of breaking down glucose using oxygen ($O_2$) to release energy and produce ATP, producing carbon dioxide ($CO_2$) and water ($H_2O$); it begins in the cytoplasm and continues in the mitochondria of eukaryotic cells.

Chemical equation for aerobic respiration

$$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy (ATP)}$$

Outer membrane (mitochondria)

The outer boundary membrane that surrounds the mitochondrion.

Inner membrane (mitochondria)

The mitochondrial membrane that contains the electron transport chain and ATP synthase.

Cristae

Folds of the inner mitochondrial membrane that function to increase surface area.

Matrix (mitochondria)

The fluid-filled space inside the inner membrane where pyruvate oxidation and the Krebs cycle occur.

Intermembrane space

The compartment in the mitochondrion where $H^+$ ions accumulate during electron transport chain activity.

Glycolysis

Stage 1 of aerobic respiration occurring in the cytoplasm (cytosol), in which one glucose molecule ($6$ carbons) is broken into two pyruvate molecules ($3$ carbons each), producing a net gain of $2\text{ ATP}$ (uses $2\text{ ATP}$, produces $4\text{ ATP}$) and $2\text{ NADH}$, while directly requiring no oxygen and producing no $CO_2$.

Pyruvate oxidation

Stage 2 of aerobic respiration occurring in the mitochondrial matrix of eukaryotes, converting two pyruvate molecules into two acetyl-CoA molecules, producing $2\text{ NADH}$ and $2\text{ CO}_2$ per glucose while producing $0\text{ ATP}$ directly.

Krebs cycle (Citric Acid Cycle)

Stage 3 of aerobic respiration located in the mitochondrial matrix, where acetyl-CoA combines with oxaloacetate to form citrate; per glucose molecule (two turns), it produces $2\text{ ATP}$ (or GTP), $6\text{ NADH}$, $2\text{ FADH}_2$, and $4\text{ CO}_2$, and does not directly use oxygen.

Oxaloacetate

The molecule in the mitochondrial matrix that combines with acetyl-CoA to form citrate, which is subsequently regenerated through a cyclical series of reactions.

Electron Transport Chain (ETC)

A series of protein complexes located in the inner mitochondrial membrane where high-energy electrons donated by NADH and $FADH_2$ are passed along to drive the pumping of $H^+$ ions into the intermembrane space.

ATP synthase

An enzyme embedded in the inner mitochondrial membrane through which $H^+$ ions flow back down their gradient into the matrix to synthesize ATP.

Chemiosmosis

The process occurring in the inner mitochondrial membrane where $H^+$ ions flow back into the matrix through ATP synthase, producing most of the cell's ATP.

Oxygen ($O_2$)

The final electron acceptor in the electron transport chain, which combines with electrons and $H^+$ to form water ($H_2O$).