Inside the Mitochondria: Cellular Respiration

Vocabulary flashcards identifying key terms, structures, and processes involved in cellular respiration inside the mitochondria.

Matrix

The fluid-filled inner compartment of the mitochondrion, similar to cytoplasm, where the preparatory reaction and the citric acid cycle occur.

Cristae

The folds of the inner mitochondrial membrane where the electron transport chain and ATP synthase enzymes are located.

Preparatory Reaction

A phase in the mitochondrial matrix where a $3$-carbon pyruvic acid is converted into a $2$-carbon acetyl group attached to CoA, generating $1\text{ NADH}$ and releasing $1\text{ CO}_2$ per pyruvic acid.

Acetyl CoA

A molecule formed in the mitochondrial matrix when a $2$-carbon acetyl group binds with coenzyme A, serving as the substrate for the citric acid cycle.

Citric Acid

The $6$-carbon molecule formed in the first step of the citric acid cycle when a $2$-carbon acetyl group combines with a $4$-carbon sugar.

Citric Acid Cycle

A cyclic pathway in the matrix that completely oxidizes acetyl groups to carbon dioxide, yielding $2\text{ ATP}$, $6\text{ NADH}$, $2\text{ FADH}_2$, and $4\text{ CO}_2$ per glucose molecule.

Electron Transport Chain

A series of carrier proteins in the cristae that pass high-energy electrons from NADH and FADH2 to pump protons and extract energy for ATP production.

Oxygen

The final electron acceptor at the end of the electron transport chain during cellular respiration.

Intermembrane Space

The space between the inner mitochondrial membrane (cristae) and the outer membrane where protons are pumped to generate a concentration gradient.

ATP Synthase

An enzyme located on the inner mitochondrial membrane that utilizes the flow of protons down their concentration gradient from the intermembrane space to produce ATP.

Fermentation

An anaerobic process that a cell must perform to process glucose when oxygen is unavailable and electron carriers become saturated with electrons.

NADH vs FADH2 Energy Yield

Electrons dropped off by NADH cause protons to be pumped across $3$ pumps, whereas electrons from FADH2 result in $2$ proton pumps, making NADH carry more stored energy.

Total Cellular Respiration ATP Yield

The total production of $36\text{ to }38\text{ ATP}$ per glucose molecule, with $32\text{ to }34\text{ ATP}$ produced specifically by the electron transport chain.