AP Biology Ultimate Guide (copy)

Element

A substance that cannot be broken down into simpler substances by chemical means.

Trace Elements

Elements required by an organism only in very small quantities, including iron (Fe), iodine (I), and copper (Cu).

Atom

The basic unit of life which is the building block of physical matter.

Proton

A positively charged particle found within an atom.

Neutron

An uncharged particle found within the nucleus of an atom.

Electron

A negatively charged particle that orbits around the nucleus of an atom.

Isotope

Atoms of the same element that have the same number of protons but differ in the number of neutrons.

Ionic Bond

A bond formed between two atoms when one or more electrons are transferred from one atom to another.

Covalent Bond

A bond formed when electrons are shared between atoms.

Hydrogen Bond

A weak chemical bond that forms when a hydrogen atom covalently bonded to one atom, is attracted to another atom.

Cohesion

The tendency of water molecules to stick together due to hydrogen bonding.

Adhesion

The tendency of water molecules to stick to other substances.

pH Scale

A scale used to measure the acidity or alkalinity of a solution, ranging from 1 to 14.

Organic Molecule

Molecules that contain carbon.

Monomer

The individual building blocks of a polymer.

Polymer

Long chains of repeating monomer units.

Carbohydrates

Organic compounds consisting of carbon, hydrogen, and oxygen, typically in a ratio of 1:2:1.

Monosaccharides

The simplest form of carbohydrates, which serve as energy sources for cells.

Disaccharides

Carbohydrates formed from two monosaccharides joined together.

Polysaccharides

Complex carbohydrates made up of many monosaccharides.

Proteins

Molecules that perform a variety of functions in the body, composed of amino acid chains.

Amino Acids

The building blocks of proteins, containing a central carbon, amino group, carboxyl group, hydrogen, and R-group.

Peptide Bond

The bond formed between two amino acids during protein synthesis.

Triglycerides

The most common type of lipid, made up of a glycerol molecule and three fatty acid chains.

Phospholipids

Lipids with two fatty acid tails and a phosphate head that form cell membranes.

Nucleic Acids

Large biomolecules, essential for all known forms of life, including DNA and RNA.

Cell Cycle

The series of stages that cells go through for growth, replication, and division.

Mitosis

A process of cell division that results in two identical daughter cells.

Meiosis

A special type of cell division that produces haploid gametes for sexual reproduction.

Mutation

A change in the DNA sequence that can lead to variations in traits.

Natural Selection

The process where organisms better adapted to their environment tend to survive and reproduce.

Evolution

The change in the heritable traits of biological populations over successive generations.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with carbon dioxide and water.

Cellular Respiration

The process through which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Enzyme

Biological catalysts that speed up chemical reactions by lowering activation energy.

Catalyst

A substance that increases the rate of a chemical reaction without itself undergoing any permanent change.

Signal Transduction

The process by which a cell responds to signals from its environment.

Gametes

Haploid sex cells that combine during fertilization to form a diploid zygote.

Phenotype

The observable physical traits of an organism resulting from the expression of its genotype.

Genotype

The genetic makeup of an organism, including all alleles present.

Homozygous

An organism with two identical alleles for a trait.

Heterozygous

An organism with two different alleles for a trait.

Law of Segregation

Mendel’s principle that during the formation of gametes, the two alleles for a gene segregate from each other.

Dihybrid Cross

A genetic cross involving two traits that are located on different chromosomes.

Ecology

The study of interactions between living organisms and their environment.

Ecosystem

A biological community of interacting organisms and their physical environment.

Symbiosis

An interaction between two different organisms living in close physical proximity.

Primary Consumers

Organisms that consume producers (herbivores in an ecosystem).

Trophic Level

The position an organism occupies in a food chain.

Biomass

The total mass of living matter within a given area or volume.