Bioenergetics and Glycolysis

Flashcards testing vocabulary and key concepts from the lecture on bioenergetics, ATP synthesis, and glycolysis.

Cellular oxidation of palmitic acid

The enzymatic pathway converting palmitic acid into energy, expressed as $\text{CH}_3-(\text{CH}_2)_{14}-\text{COOH} + 23\text{O}_2 + 130\text{ADP} + 130\text{P} \rightarrow 16\text{CO}_2 + 146\text{H}_2\text{O} + 130\text{ATP} + \text{HEAT } (1,384\text{ kcal})$.

Standard conditions for free energy change ($\Delta G^0$)

The standard baseline conditions for measuring free energy change: a temperature of $25^\text{o}\text{C}$, pressure of $1.0\text{ Atm}$, pH of $7.00$, and equal concentrations of reactants and products at $1\text{ mol/liter}$.

Actual free energy change equation

The mathematical equation used to calculate free energy change under nonstandard cellular conditions: $\Delta G = \text{D}G^0 + 2.3RT \text{log}\text{([product]/[reactant])}$.

Phosphoenolpyruvate free energy of hydrolysis

The standard free energy change released upon hydrolysis of phosphoenolpyruvate, equal to $\Delta G^0 = -14,800\text{ cal}$.

Standard free energy of ATP hydrolysis

The standard free energy released when ATP is hydrolyzed to ADP and $\text{P}_i$, equal to $\Delta G^0 = -7,300\text{ cal/mol}$.

Substrate level phosphorylation

The direct enzyme-mediated transfer of a phosphate group from a high-energy donor molecule directly to ADP, such as the phosphorylation of ADP by phosphocreatine in muscle.

Oxidative phosphorylation

The indirect synthesis of ATP driven by the oxidation of a metabolite using $\text{O}_2$ (reducing oxygen to water) and passing electrons through intermediates to phosphorylate ADP.

Glycolysis

The metabolic pathway occurring in the cytosol of cells that converts glucose into pyruvate or lactate to supply quick energy.

Anaerobic glycolysis

The pathway of glycolysis occurring in the absence of oxygen that yields a net of $2\text{ ATP}$ per glucose molecule and converts pyruvate to lactate.

Aerobic glycolysis

The glycolytic pathway operating in the presence of oxygen, generating a net yield of $6-8\text{ ATP}$ equivalents per glucose molecule through mitochondrial oxidative phosphorylation.

Cori Cycle

The inter-organ metabolic pathway where lactate produced by anaerobic glycolysis in muscle travels through the blood to the liver to be converted back into glucose via gluconeogenesis.

Regulation of enzyme activity

The four main methods of cellular enzyme control: competition for catalytic sites, covalent modification (e.g., via hormone stimulation), allosteric modulation, and changes in enzyme quantity.

Fructokinase

The enzyme that phosphorylates fructose using ATP to produce fructose-1-phosphate, initiating the process of fructose entry into the glycolytic pathway.

Galactokinase

The enzyme that catalyzes the ATP-dependent phosphorylation of galactose to form galactose-1-phosphate.

Irreversible reactions of glycolysis

The three non-equilibrium steps of glycolysis catalyzed by the enzymes hexokinase, phosphofructokinase-1, and pyruvate kinase.