Chapter 15

Metabolism

The sum of all chemical reactions in a cell, involving catabolism (breakdown of larger molecules) and anabolism (synthesis of larger molecules).

ATP

Adenosine triphosphate, the storage form of energy in a cell and considered the "energy currency" of the cell.

Laws of Thermodynamics

Living organisms must follow these laws, including the conservation of energy and the increase in entropy in the universe.

Standard States for Free-Energy Changes

Conditions under which free-energy changes are measured, including pure solids, gases at 1 atm, and solutions at 1M concentration.

Equilibrium Constant

Indicates the direction of a spontaneous process based on the value compared to 1, affecting the standard free energy change (∆Gº).

Coupling of Production and Use of Energy

In metabolism, energetically unfavorable reactions are coupled to favorable ones to drive reactions forward, often involving ATP.

Redox Reactions

Involves the transfer of electrons from a donor to an acceptor, with oxidation (loss of electrons) and reduction (gain of electrons) processes.

Nernst Equation

Relates the standard reduction potential to the actual cell potential under non-standard conditions.

NAD+/NADH and FAD/FADH2

Coenzymes involved in redox reactions, with NAD+ being the oxidized form and NADH the reduced form, while FAD takes on electrons to form FADH2.

Acetyl-CoA

Donor of acetyl groups in metabolic pathways, important in the biosynthesis of fatty acids and other processes.