AP bio chapters 1-5

Carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), sulfur (S)

The six elements that make up almost all living matter, often referred to as CHNOPS.

Atomic number

The number of protons in an atom's nucleus; it uniquely identifies the element.

Proton

Subatomic particle with a +1 charge and a mass of about 1 amu.

Neutron

Subatomic particle with no charge and a mass of about 1 amu.

Electron

Subatomic particle with a -1 charge and a mass of about 0.0005 amu.

Isotope

An atom of the same element with the same number of protons but a different number of neutrons.

Covalent bond

A bond formed when two atoms share electrons.

Polar covalent bond

A covalent bond where electrons are shared unequally, creating partial charges.

Ionic bond

A bond formed when one atom transfers electrons to another, resulting in oppositely charged ions.

Hydrogen bond

A weak attraction between a partially positive hydrogen atom and a partially negative electronegative atom.

Cohesion

Attraction between molecules of the same substance.

Adhesion

Attraction between molecules of different substances.

Specific heat

The amount of heat required to raise the temperature of 1 gram of a substance by 1°C.

Heat of vaporization

The amount of energy required for water to evaporate, approximately 2260 J/g at 100°C.

Hydrophobic

Substances that do not interact well with water and tend to avoid it.

Hydrophilic

Substances that interact with or are attracted to water.

Monosaccharide

The simplest form of carbohydrates, consisting of one sugar unit.

Disaccharide

A carbohydrate composed of two monosaccharide units.

Polysaccharide

A carbohydrate made up of multiple sugar units.

Peptide bond

A covalent bond that links two amino acids together.

Primary structure

The specific amino acid sequence of a protein, held together by peptide bonds.

Secondary structure

Local folding of a protein, stabilized by hydrogen bonds.

Tertiary structure

The overall 3-D shape of a protein, caused by interactions between R groups.

Quaternary structure

The arrangement of multiple polypeptide chains into a single functional protein.

Purine

A nitrogenous base with two rings; examples include adenine (A) and guanine (G).

Pyrimidine

A nitrogenous base with one ring; includes cytosine (C), thymine (T), and uracil (U).