Chapter 3: Energy, Catalysis, & Biosynthesis

Vocabulary flashcards covering key concepts from the lecture on Energy, Catalysis, & Biosynthesis, including metabolic pathways, laws of thermodynamics, energy transfer, and reaction dynamics.

What are Enzymes, and what is their primary function in biological systems?

$\rightarrow$ Enzymes are biological catalysts, typically proteins, that accelerate the rate of specific biochemical reactions by lowering the activation energy without being consumed in the process. They exhibit high specificity for their substrates.

Catabolic Pathways

Biochemical pathways that break down food molecules into useful forms of energy and building blocks, releasing heat.

Anabolic Pathways

Biochemical pathways that use energy and building blocks to synthesize the many molecules that form the cell.

Metabolism

The sum total of all the chemical reactions a cell needs to survive, grow, and reproduce.

Second Law of Thermodynamics

States that disorder can only increase, and spontaneous processes increase entropy.

Entropy

A measure of a system’s disorder.

First Law of Thermodynamics

States that energy cannot be created or destroyed, only converted from one form to another.

Photosynthesis

The process by which solar energy is captured to manufacture sugars from H₂O and CO₂, producing O₂ and activated carriers (ATP, NADPH).

Cellular Respiration

The process that uses oxygen to break down sugars and other organic molecules to produce useful energy for cells, releasing CO₂ and H₂O.

Oxidation

The removal of electrons from an atom.

Reduction

The addition of electrons to an atom.

Free Energy (G)

Energy that can be harnessed to do work.

Energetically Favorable Reactions

Reactions that are 'downhill,' spontaneous, and result in a loss of free energy, increasing disorder.

Activation Energy

The energy barrier that must be overcome to initiate a chemical reaction.

Free-Energy Change (ΔG)

A measure that determines if a reaction can occur spontaneously; a negative ΔG indicates an energetically favorable reaction.

Reaction Coupling

The process where an energetically unfavorable reaction is driven by linking it to an energetically favorable reaction, such that the net ΔG is negative.

ATP Hydrolysis

A process that releases stored energy from ATP, often used to drive energetically unfavorable reactions by joining two molecules together.

Equilibrium

The state where forward and reverse reaction rates are equal, resulting in no net change in product or substrate concentrations and a ΔG of 0.