AP Biology Guide

Element

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

Isotope

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

Covalent Bond

A bond formed when electrons are shared between atoms.

Ionic Bond

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

Hydrogen Bond

A weak chemical bond formed when a hydrogen atom covalently bonded to one electronegative atom is attracted to another electronegative atom.

pH scale

A measure of acidity or alkalinity of a solution, ranging from 1 to 14, where 7 is neutral.

Monomer

The individual building blocks of a polymer.

Polymer

Chains of building blocks formed through dehydration synthesis reactions.

Glycosidic Linkage

The bond formed when two monosaccharides are joined together.

R-group

The variable group that determines the identity and properties of an amino acid.

Peptide Bond

The bond formed when the carboxyl group of one amino acid combines with the amino group of another.

Phospholipid

A molecule containing two fatty acid tails and one phosphate head; critical in forming cell membranes.

Activating enzyme

An enzyme that helps speed up reactions by lowering the activation energy.

Enzyme Specificity

The concept that each enzyme catalyzes only one specific kind of reaction.

Endocytosis

The process by which cells engulf large particles or fluids into their interior.

Homeostasis

The maintenance of relatively stable internal conditions in an organism.

Interphase

The stage of the cell cycle where the cell grows and DNA is replicated.

Gene

A unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Mutation

A change in the genetic code that can result in altered traits or functions.

Natural Selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Carrying capacity

The maximum number of individuals of a species that an environment can sustain.

Biotic Factors

Living parts of an ecosystem that affect the survival and reproduction of organisms.

Abiotic Factors

Non-living parts of an ecosystem that shape the environment.

Symbiosis

A close and often long-term interaction between two different biological species.

Ecosystem

A biological community of interacting organisms and their physical environment.

Endotherm

An animal that generates its own body heat through metabolic processes.

Exocytosis

The process of ejecting materials from a cell via vesicles.

Photosynthesis

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

Cell Respiration

The process by which cells convert glucose into energy (ATP) in the presence of oxygen.