Energy and Metabolism Lecture Notes

A set of vocabulary flashcards covering the principles of energy, thermodynamics, chemical reactions, enzyme kinetics, and metabolic pathways.

Producers

Organisms such as plants that produce energy.

Decomposers

Organisms such as fungi, bacteria, and worms that break down organic matter.

Consumers

Organisms such as animals that consume other organisms for energy.

Energy

The ability to do work.

Kinetic energy

The energy of motion, including light energy and thermal energy.

Potential energy

The energy of matter due to its location or structure, including chemical energy.

Thermodynamics

The study of energy transformations.

The First Law of Thermodynamics

The law of conservation of energy which states that energy is neither created nor destroyed, but it can be transformed; the total amount of energy before a transformation equals the total amount after.

Entropy

A measure of randomness or disorder in a system, representing how much energy is unusable.

Free Energy

Usable energy, or energy that is available to do work, represented by Gibbs free energy ($\Delta G$).

Chemical reaction

Occurs when atoms combine or change their bonding partners.

Exergonic reactions

Reactions where energy is released because reactants have more free energy than products ($-\Delta G$).

Hydrolysis

A chemical process where a complex molecule plus $H_2O$ yields simple molecules.

Endergonic reactions

Reactions where energy is required because products have more free energy than the reactants ($+\Delta G$).

Condensation

The reverse of hydrolysis, such as the reaction: $\text{glucose} + \text{fructose} \rightarrow \text{sucrose} + H_2O$.

Activation Energy ($E_a$)

The amount of energy required for a chemical reaction to occur.

Enzymes

Catalysts that speed up the rate of a reaction by reducing the activation energy.

Substrate

The molecule an enzyme binds and acts on.

Active site

The specific part of an enzyme that binds the substrate.

Induced fit

The process where an enzyme clamps down around the substrate to form a tight fit.

Exhibition of Specificity

The property of enzymes only acting on specific substrates, such as human enzymes hydrolyzing starch but not the equatorial glycosidic bonds in cellulose.

Denaturation

The process where enzymes lose their structure and function at extreme pH or temperature ranges.

Competitive Inhibition

When an inhibitor binds to the active site of the enzyme, physically blocking the substrate.

Allosteric Inhibition

When an inhibitor binds to a part of the enzyme outside of the active site, changing its shape to prevent activity.

Allosteric Activation

When a molecule binds to an enzyme and changes its shape to an active form.

Metabolism

A series of chemical reactions catalyzed by enzymes, including both catabolism and anabolism.

Catabolism

Metabolic pathways where larger molecules are broken down into smaller ones and energy is released.

Anabolism

Metabolic pathways where small molecules are built into large ones, which requires energy.

ATP (Adenosine triphosphate)

The primary energy currency of the cell.

Reduction

The gain of one or more electrons by a molecule.

Oxidation

The loss of one or more electrons from a molecule.

Redox reactions

Chemical reactions where energy is transferred through the transfer of electrons.

Coenzyme

A substance that enhances an enzyme's activity and acts as an electron carrier, such as NAD and FAD.

Oxidative phosphorylation

The process that couples the oxidation of NADH to the synthesis of ATP from ADP and $P_i$.