Energy & Metabolism

This set of flashcards covers vocabulary and key concepts from Chapter 6: Energy and Metabolism, including thermodynamic laws, reaction types, redox reactions, and ATP function.

Metabolism

All chemical reactions that take place in the cell, which may use or release energy.

1st Law of Thermodynamics

The principle that energy is conserved and cannot be created or destroyed, only converted.

2nd Law of Thermodynamics

The principle that energy transformations are inefficient and every reaction loses some energy to heat.

Entropy

A measure of randomness or disorder that always increases during energy transformations.

Chemical equilibrium

The state where forward and reverse reaction rates are equal, resulting in a stable configuration or ratio.

Potential Energy

Stored energy available to do work, found in chemical bonds of molecules like glycogen, TG, and ATP, or in concentration gradients.

Kinetic Energy

Energy being used to do work, such as moving objects or performing chemical reactions in cells.

Free Energy

The energy available to do the work associated with kinetic energy.

Anabolic Reactions

Processes that build or synthesize larger molecules, require an input of energy, and increase potential energy.

Catabolic Reactions

Processes that break or decompose molecules, release energy, and provide free energy used to build ATP.

Endergonic

A description of a reaction that requires an input of energy to make products.

Exergonic

A description of a reaction that involves releasing energy from reactants.

Redox Reactions

Oxidation-Reduction reactions involving the transfer of electrons between molecules to release energy stored in organic molecules.

Reduction

The gain of electrons by a molecule, which increases its potential energy.

Oxidation

The loss of electrons from a molecule, which decreases its potential energy.

ATP (Adenosine Triphosphate)

The energy currency of a cell that powers cellular work by energizing molecules and changing the shapes of proteins.

ATP Hydrolysis

The reaction $ATP + H_2O \rightarrow ADP + P_i + \text{Free Energy}$ which provides immediate power to coupled reactions.

Sodium Potassium Pump cycle

A process consuming 1 ATP to move $3Na^+$ outside the cell and $2K^+$ inside the cell.

Phosphorylation

The process of attaching a phosphate group ($P_i$) and free energy to a molecule, such as a pump, to trigger a conformation change.

Heat

Random molecular movements representing energy lost during transformations; it is the measure commonly used for energy.