AP Biology Review

A collection of key terms and definitions from AP Biology lecture notes for exam preparation.

Element

Substances that cannot be broken down into smaller substances by chemical means.

Essential Elements of Life

Four elements that make up 96% of the mass of living things: Oxygen, Carbon, Hydrogen, and Nitrogen.

Subatomic Particle

Particles smaller than an atom; includes protons, neutrons, and electrons.

Proton

Subatomic particle found in the nucleus, positively charged.

Neutron

Subatomic particle found in the nucleus, has no charge.

Electron

Negatively charged subatomic particle that orbits the nucleus.

Valence Electrons

Electrons in the outermost shell which determine an atom's chemical behavior.

Ionic Bond

Bond formed by the transfer of electrons from one atom to another, resulting in oppositely charged ions.

Covalent Bond

Bond formed when two atoms share electrons.

Hydrogen Bond

Weak attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Polarity of Water

Water's unique structure, where electrons are shared unequally, causing partial charges.

Acid

A solution that contains a high concentration of H+ ions.

Base

A solution that contains a high concentration of OH- ions.

Organic Molecule

Compounds primarily made of carbon atoms.

Functional Group

Specific group of atoms within a molecule that is responsible for the characteristic reactions of that molecule.

Monomer

Small building block molecules that join to form polymers.

Polysaccharide

Carbohydrates formed by the linkage of many monosaccharides.

Amino Acid

Monomer of proteins that consist of a central carbon, an amino group, a carboxyl group, a hydrogen, and an R group.

Enzyme

Biological catalyst that speeds up reactions by lowering activation energy.

ATP

Adenosine triphosphate, the energy currency of the cell.

Photosynthesis Reaction

6CO2 + 6H2O → C6H12O6 + 6O2, the process of converting light energy into chemical energy.

Glycolysis

The process of splitting glucose into pyruvate, yielding energy (ATP) and NADH.

DNA Structure

Made up of nucleotides linking together to form a double helix.

Mutation

An error in the genetic code caused by damage or incorrect repairs.

Natural Selection

The process by which individuals with favorable traits are more likely to reproduce.

Mendelian Genetics

The study of heredity and the variation of inherited traits.

Population Growth Rate

Calculated as r = (births - deaths)/N, where N is the population size.

Ecosystem

Community of living organisms interacting with their physical environment.

Homeostasis

The maintenance of stable internal conditions in an organism.

Altruistic Behavior

Unselfish behavior that benefits another organism at the individual’s expense.