A&P Ch 3 Energy, Enzymes, and Cellular Respiration Vocabulary

Vocabulary flashcards covering energy forms, thermodynamics, chemical reactions, enzyme structure and kinetics, and stages of cellular respiration based on the lecture notes.

Potential Energy

Energy of position or stored energy.

Kinetic Energy

Energy of motion.

Chemical Energy

One form of potential energy that is released when chemical bonds are broken.

Electrical Energy

A form of kinetic energy involving the movement of charged particles.

Mechanical Energy

A form of kinetic energy present in objects in motion due to an applied force.

Sound Energy

A form of kinetic energy caused by molecule compression from a vibrating object.

Radiant Energy

A form of kinetic energy consisting of electromagnetic waves.

Heat

Kinetic energy resulting from the movement of atoms, ions, and molecules.

Triglycerides

High-energy molecules used for long-term energy storage in adipose connective tissue.

Glucose

High-energy molecule stored in the liver and muscle tissue in the form of glycogen.

ATP

High-energy molecule stored in all cells in limited amounts, produced continuously, and used immediately.

First Law of Thermodynamics

Law stating that energy can neither be created nor destroyed.

Second Law of Thermodynamics

Law stating that when energy is transformed, some energy is lost to heat.

Chemical Reaction

Process occurring when either the chemical bonds of a molecular structure are broken and new ones are formed, or electrons are transferred.

Synthesis Reaction

A category of chemical reaction where two or more atoms are combined to make a larger chemical structure.

Decomposition Reaction

A category of chemical reaction where a large molecule is broken down into smaller chemical structures.

Exchange Reaction

A chemical reaction where atoms, molecules, ions, or electrons are exchanged between two chemical structures.

Exergonic Reaction

A reaction occurring when reactants at the start have more potential energy in their chemical bonds than the products, causing energy to go out (such as decomposition reactions).

Endergonic Reaction

A reaction occurring when reactants have less energy within their chemical bonds than the products, requiring energy to be supplied (such as synthesis reactions).

ATP Cycling

The continuous breaking down and formation of ATP.

Irreversible Chemical Reaction

A reaction where reactants converted to a product yield a net loss of reactants and a net gain in products.

Reversible Chemical Reaction

A reaction where reactants become products at a rate equal to products becoming reactants once equilibrium is reached.

Chemical Reaction Rate

How quickly a chemical reaction takes place, which determines the amount of product formed per unit of time.

Activation Energy

The energy required to break existing chemical bonds for a chemical reaction to proceed.

Enzymes

Biologically active catalysts that facilitate chemical changes in the human body by decreasing activation energy.

Active Site

A grooved region on globular proteins formed by amino acids in a 3-D structure.

Induced Fit Model

The process where a substrate enters an enzyme's active site and is conformed by slightly changing shape.

Cofactors

Nonprotein structures that are either inorganic or organic substances associated with a certain enzyme to help ensure a reaction occurs.

Oxidoreductase

An enzyme class that transfers electrons from one substance to another.

Transferase

An enzyme class that transfers a functional group.

Hydrolase

An enzyme class that splits a chemical bond using water.

Isomerase

An enzyme class that converts one isomer to another.

Ligase

An enzyme class that bonds two molecules together.

Lyase

An enzyme class that splits a chemical bond in the absence of water.

Exceptions to Enzyme Naming Conventions

Enzymes that do not end with the standard "ase" suffix, specifically pepsin, trypsin, and chymotrypsin.

Enzyme Saturation

The state when so much substrate is present that all enzyme molecules are actively engaged in the chemical reaction, resulting in no further increase in reaction rate.

Optimum Temperature for Human Enzymes

Around $40^\text{C}$, where enzyme activity increases to facilitate elimination of infectious agents; more severe increases denature the enzyme.

Optimum pH for Human Enzymes

Around $\text{pH } 6\text{--}8$, where changes in $H^+$ concentrations disrupt electrostatic interactions and cause denaturation.

Competitive Inhibitors

Substances that resemble the substrate and bind to the active site of an enzyme, competing with the substrate to turn it off.

Noncompetitive Inhibitors

Substances that do not resemble the substrate and function to inhibit an enzyme by binding to an allosteric site, inducing a conformational change.

Metabolic Pathway

A sequence composed of numerous enzymes to convert a specific substrate to a final product, where the product of one enzyme becomes the product/substrate of another.

Multienzyme Complex

A group of enzymes that are physically attached to each other through noncovalent bonds.

Negative Feedback in Enzyme Regulation

A mechanism where the product from a metabolic pathway acts as an allosteric inhibitor to turn off an enzyme early in the metabolic pathway to prevent overproduction.

Glucose Oxidation

The loss of electrons from the breakdown of glucose molecules, represented by $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O$.

Substrate-Level Phosphorylation

Direct method of transferring a phosphate group from a reactive substrate to ADP to create ATP.

Oxidative Phosphorylation

Indirect method where cells use enzymes to oxidize nutrients to produce ATP.

Glycolysis

Anaerobic stage of cellular respiration occurring in cytosol where glucose is broken down into two pyruvate molecules, yielding a net $2\text{ ATP}$ and $2\text{ NADH}$.

Intermediate Stage

Aerobic link between glycolysis and the citric acid cycle occurring twice per glucose in the mitochondrial matrix, catalyzed by pyruvate dehydrogenase to form acetyl-CoA, $CO_2$, and NADH.

Pyruvate Dehydrogenase

The multienzyme complex that brings together pyruvate and CoA to make acetyl-CoA during the intermediate stage.

Citric Acid Cycle

Aerobic stage in the mitochondrial matrix where acetyl-CoA is converted to $2\text{ }CO_2$ molecules, transferring energy to form $1\text{ ATP}$, $3\text{ NADH}$, and $1\text{ FADH}_2$.

Electron Transport System

A series of protein complexes and mobile molecules in the inner mitochondrial membrane that transfers electrons from NADH and FADH2 to create an energy gradient for making ATP.

Beta-Oxidation

The enzymatic conversion of fatty acids to form acetyl-CoA so they can enter cellular respiration at the citric acid cycle aerobically.

Deaminated Amino Acids Entry

Molecules formed after the amine group waste product is removed and converted to urea for kidney excretion, which enter cellular respiration at glycolysis, the intermediate stage, or the citric acid cycle.