Biology Chapter 8 & 9 Vocab

Activation Energy

Minimum energy required to start a chemical reaction

Active Site

The region on an enzyme where the substrate binds and the reaction occurs

ADP

A lower-energy molecule formed when ATP loses a phosphate group.

Allosteric Regulation

Inhibitor binds elsewhere on the enzyme, changing its shape and reducing activity.

Anabolic Pathways

Build complex molecules from simpler ones, requiring energy.

ATP

The main energy currency of the cell; stores and transfers energy.

Catabolic Pathways

Break down complex molecules into simpler ones, releasing energy.

Catalyst

A substance that speeds up a chemical reaction without being consumed.

Coenzyme

A non-protein organic molecule that helps enzymes function (e.g., vitamins).

Cofactor

A non-protein helper (often a metal ion) required for enzyme activity.

Competitive Inhibition

Inhibitor competes with the substrate for the enzyme's active site.

Electron Acceptor

A substance that receives electrons in a redox reaction.

Electron Donor

A substance that gives away electrons in a redox reaction.

Endergonic

A reaction that requires energy input (non-spontaneous).

Endothermic

A reaction that absorbs heat from its surroundings.

Enthalpy (H)

Total heat content of a system; reflects energy changes during chemical reactions.

Entropy (S)

Measure of disorder or randomness in a system.

Enzyme

A biological catalyst that speeds up chemical reactions in living organisms.

Exergonic

A reaction that releases energy (spontaneous).

Exothermic

A reaction that releases heat to its surroundings.

Feedback Inhibition

A process where the end product of a pathway inhibits an earlier step to regulate production.

First Law of Thermodynamics

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

Gibbs Free Energy (ΔG)

Energy available to do work; determines if a reaction is spontaneous.

Heat

Transfer of thermal energy from a hotter object to a cooler one.

Kinetic Energy

Energy of motion; the energy an object has due to its movement.

Metabolic Pathways (Metabolism)

Series of chemical reactions in a cell that build up or break down molecules.

Oxidation Reaction

Loss of electrons from a molecule, atom, or ion.

Phosphorylation

Addition of a phosphate group to a molecule, often activating or energizing it.

Potential Energy

Stored energy due to an object's position or arrangement.

Redox Reaction

A chemical reaction involving both oxidation and reduction.

Reduction Reaction

Gain of electrons by a molecule, atom, or ion.

Second Law of Thermodynamics

Energy transformations increase entropy (disorder); energy tends to disperse.

Substrates

Reactants that bind to an enzyme's active site and undergo a chemical reaction.

Cellular respiration

process of breaking down glucose to produce ATP

Aerobic respiration

cellular process in the cell uses oxygen to metabolize glucose and produce energy in the form of adenosine triphosphate 

Anaerobic respiration

What is the term for respiration that occurs without oxygen?

Fermentation

What is the byproduct of anaerobic respiration in yeast?

NAD+

What molecule is reduced to form NADH during cellular respiration?

It carries electrons to the electron transport chain.

What is the role of FADH2 in cellular respiration?

In the mitochondria

Where does the citric acid cycle occur within the cell?

What is the main purpose of glycolysis?

To convert glucose into pyruvate and produce a small amount of ATP.

Oxidative phosphorylation

What process generates the majority of ATP during cellular respiration?

What is the function of ATP synthase?

To synthesize ATP from ADP and inorganic phosphate during chemiosmosis.