Unit 3, Cellular Energetics

Activation Energy

The minimum energy required for a chemical reaction to occur, allowing reactants to reach the transition state.

Aerobic respiration

A metabolic process that requires oxygen to convert glucose into energy, producing carbon dioxide and water as byproducts.

Anaerobic fermentation

A metabolic process that occurs without oxygen, converting glucose into energy while producing byproducts such as lactic acid or ethanol.

Electron transport chain

A series of protein complexes and other molecules embedded in the inner mitochondrial membrane that transfer electrons through redox reactions, ultimately producing ATP through oxidative phosphorylation.

Endergonic

reactions that absorb energy, often used to synthesize complex molecules.

Entropy

A measure of disorder or randomness in a system, reflecting the number of ways a system can be arranged. In thermodynamics, it describes how energy disperses and the inevitable tendency toward equilibrium.

Exergonic

reactions that release energy, typically associated with the breakdown of complex molecules.

First law of thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

Free energy

The amount of energy available to do work in a system, defined as the difference between the enthalpy of a system and the product of the entropy and temperature.

Krebs Cycle

A series of enzymatic reactions in cellular respiration that produces energy through the oxidation of acetyl-CoA, resulting in the generation of ATP, NADH, and FADH2.

Light dependent reactions

The initial stage of photosynthesis that converts light energy into chemical energy in the form of ATP and NADPH, occurring in the thylakoid membranes of chloroplasts.

Light independent reactions

also known as the Calvin cycle, these reactions use ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose. O

Oxidized

refers to the loss of electrons or hydrogen from a molecule, often resulting in an increase in oxidation state.

Phosphorylation

is the process of adding a phosphate group to a molecule, often used to activate or deactivate enzymes and regulate metabolic pathways.

Photons

are particles of light that carry energy. They play a crucial role in photosynthesis by providing the energy needed for light-dependent reactions.