BIOL 190 Cellular Respiration Study Set

These vocabulary cards cover the introductory concepts, pathways, and detailed molecular steps of cellular respiration, including aerobic and anaerobic processes, fermentation, and the specific mechanics of the electron transport chain and chemiosmosis.

ATP

The universal energy molecule of the cell used for transferring chemical energy to enzymes (proteins) for metabolism.

ADP

A lower energy state molecule containing 2 phosphates that must be recharged into ATP.

Endergonic

A reaction type where energy is required to build a molecule, such as the synthesis of ATP.

Exergonic

A reaction type where energy is released, such as when glucose is catabolized.

Aerobic respiration

A cellular process requiring $O_2$ used by most eukaryotes and some bacteria to generate $30-32$ ATP molecules per glucose.

Anaerobic respiration

A process used mostly by prokaryotes in oxygen-absent environments that uses alternative molecules like sulfur or nitrate to receive final electrons.

Methanogens

Anaerobes that produce methane in animals like cows or sheep (ruminants) and in landfills.

Fermentation

A fast, simple backup method for ATP production that does not require oxygen and generates $2$ ATP per glucose molecule.

Lactic acid fermentation

A fermentation track that produces lactate as a byproduct; performed by some bacteria, yeast, and animals.

Alcohol fermentation

A fermentation track that produces ethanol as a byproduct; performed by yeast, some bacteria, and goldfish.

Matrix

The most internal space of the mitochondrion containing circular DNA and where the Krebs Cycle occurs.

Cristae

Folds of the inner mitochondrial membrane where oxidative phosphorylation takes place.

Coenzymes

Electron carrier molecules such as $NAD^+/NADH$ and $FAD/FADH_2$ that track the movement of electrons used as "glue" to stick on new atoms.

Glycolysis

The first step of aerobic respiration occurring in the cytosol that breaks down $1 \times$ glucose into $2 \times$ pyruvate; requires a small ATP investment.

Pyruvate Oxidation

A process in the mitochondrial matrix that removes carbon dioxide ($CO_2$) to convert pyruvate into $2 \times$ Acetyl-CoA.

Krebs Cycle

A metabolic pathway in the matrix that turns $2 \times$ for each glucose and regenerates its initial molecule for each new cycle.

Oxaloacetate

The final product of the Krebs Cycle that converts to citrate when a new acetyl group is added.

Oxidative Phosphorylation

The final step of aerobic respiration consisting of the ETC and chemiosmosis; it requires oxygen gas and generates the most ATP.

Complex I

An integral membrane protein that breaks down $NADH$ into $NAD^+$ and pumps $H^+$ into the intermembrane space.

Complex II

A mitochondrial membrane protein that is NOT integral; it breaks down $FADH_2$ and passes electrons to Coenzyme Q while keeping protons in the matrix.

Coenzyme Q (CoQ)

A lipid-based vitamin and electron carrier that shuffles electrons between membrane proteins (Complex I/II to Complex III).

Cytochrome C (CytC)

A protein-based electron carrier containing an iron atom that shuffles electrons from Complex III over to Complex IV.

Oxygen ($O_2$)

The final electron acceptor in the electron transport chain which is split and combined with electrons and protons to form $H_2O$.

Chemiosmosis

The phase where a high concentration of $H^+$ in the intermembrane space diffuses back into the matrix to provide energy for ATP synthesis.

ATP Synthase

An integral diffusion channel and enzyme that rotates at ~6000 rpm to convert mechanical energy into chemical energy, generating over $100$ ATP per second.