Cellular Metabolism and Cellular Respiration

Vocabulary flashcards covering key terms and definitions of cellular metabolism, enzymes, the ATP cycle, cellular respiration, and fermentation from BIOL 1853.

Metabolism

All chemical reactions that occur in the body.

Metabolic pathways

Series of chemical reactions that begin with a particular reactant and end with a final product, where the products of one step serve as the substrates for the next step catalyzed by enzymes.

Feedback inhibition

A regulatory mechanism where an end product interacts with an enzyme early in a metabolic pathway to slow it down so the cell does not produce more product than it needs.

Enzymes

Proteins that speed up the rate of a chemical reaction without being consumed, which are reusable and typically named for the substrates they work on.

Active site

The specific area of an enzyme where the substrate binds, imparting specificity to the enzyme.

Energy of activation

The minimum energy needed to start a chemical reaction, which is lowered by enzymes.

Coenzymes

Nonprotein molecules that assist some enzymes in carrying out reactions, often having vitamins as components.

Mitochondria

Double-membraned organelles with their own DNA that convert chemical energy stored in glucose into ATP through cellular respiration.

Cristae

Folds of the inner mitochondrial membrane that contain enzymes for cellular respiration reactions.

ATP-ADP cycle

The continuous cycle where ATP is broken down into ADP and a phosphate to release energy, and energy from food is used to add a phosphate back onto ADP to regenerate ATP.

Cellular respiration

A process consisting of glycolysis, the citric acid cycle, and the electron transport chain that breaks glucose down into carbon dioxide and water to release energy slowly and produce ATP.

Glycolysis

An anaerobic metabolic pathway occurring in the cytoplasm that breaks a $6$-carbon glucose molecule into two $3$-carbon pyruvates, producing NADH and $2\text{ ATP}$.

Preparatory (prep) reaction

A reaction occurring when oxygen is available that prepares pyruvate molecules for entry into the citric acid cycle.

Citric acid cycle (Krebs cycle)

A cyclical series of enzymatic reactions in the mitochondrial matrix where acetyl CoA enters to complete the breakdown of glucose carbons, producing NADH, $FADH_2$, $2\text{ ATP}$, and releasing carbon dioxide.

Electron transport chain

A series of carrier proteins embedded in the mitochondrial cristae that accept pairs of electrons delivered by NADH and $FADH_2$, using oxygen as the final electron acceptor to generate water and ATP.

Fermentation

An anaerobic process occurring when oxygen is absent, allowing glycolysis to produce $2\text{ ATP}$ per glucose while producing toxic lactate.

Degradation reaction

An enzymatic process in which a single substrate is broken down into smaller products.

Synthesis reaction

An enzymatic process in which smaller substrates are combined to form a larger product.