Energy & Metabolism - Chapter 6 Flashcards

Flashcards covering key terms and concepts from Chapter 6: Energy & Metabolism, including thermodynamics, chemical equilibrium, redox reactions, ATP function, and enzyme kinetics.

Metabolism

The sum of all chemical reactions that take place in a cell, which may either use or release energy.

$1^{st}$ Law of Thermodynamics

The law stating that energy is conserved; it cannot be created or destroyed, only converted from one form to another.

$2^{nd}$ Law of Thermodynamics

The law stating that energy transformations are inefficient, with every reaction losing some energy as heat, which increases entropy.

Entropy

A measure of randomness or molecular movement; it always increases during energy transformations.

Chemical Equilibrium

A state in a reversible chemical reaction where the forward and reverse reaction rates are equal, resulting in a stable ratio of components.

Potential Energy

Stored energy available to do work, such as chemical energy in the bonds of $ATP$ or concentration gradients of molecules.

Kinetic Energy

Energy being used to do work, typically characterized by moving objects or powering reactions in cells.

Free Energy

The energy available to perform work within a system.

Anabolic Reactions

Metabolic reactions that build or synthesize larger molecules from smaller ones; they are endergonic and require an input of energy.

Catabolic Reactions

Metabolic reactions that break down or decompose larger molecules; they are exergonic and release free energy.

Endergonic

A type of reaction that requires an input of energy to transform reactants into products, resulting in increased potential energy.

Exergonic

A type of reaction that releases energy from reactants, resulting in the generation of free energy.

Reduction

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

Oxidation

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

Redox Reactions

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

$ATP$ (Adenosine Triphosphate)

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

Phosphate Group

A high-energy molecule containing highly electronegative oxygen atoms that hog electrons, making it an effective energy currency component.

ATP Hydrolysis

The spontaneous dissociation reaction represented as $ATP + H_2O \rightarrow ADP + P_i + \text{Free Energy}$, which is often coupled to other reactions.

Sodium Potassium Pump

A cellular mechanism that uses cycle of $1$ $ATP$ to transport $3Na^+$ outside the cell and $2K^+$ inside the cell.

Enzyme

A biological catalyst that facilitates chemical reactions within a cell.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed by the reaction itself.

Active Site

The specific region of an enzyme where the substrate binds, often described by the Lock-and-Key model.

Substrate

The specific reactant molecule upon which an enzyme acts.

Competitive Inhibition

A form of enzyme inhibition where a molecule other than the substrate binds to the active site, preventing the reaction.

Non-Competitive Inhibition

A form of enzyme inhibition where a molecule binds to a site other than the active site, changing the enzyme's shape and reducing its activity.

Denaturation

The loss of an enzyme's three-dimensional structure and function, often caused by changes in temperature or $pH$.

Co-factors and Co-enzymes

Inorganic or organic substances that assist enzymes in performing their catalytic functions.