AP BIO Module 1-2

matter

material that makes physical objects

atom

the basic unit of matter

molecule

a chemical formed of two or more atoms

organic molecule

a molecule made of carbon

nucleus

the dense, central part of an atom

proton

an atomic particle of the nucleus that carriers a positive charge

neutron

an atomic particle of the nucleus that carries no charge

electron

an atomic particle that moves around the nucleus and carries a negative charge

atomic number

the number of protons in an element

element

a chemical that cannot be split into other chemicals

atomic mass

the total mass of an atom; consists of the number of protons and neutrons in the atom

isotope

one or two or more forms of the same element with different numbers of neutrons

ion

an electrically charges atom

energy level

an area in space where electrons circle around the nucleus. also called an electron shell

electron shell

an area in space where electrons circle around the nucleus. also called an electron level

valence electron

an electron in the outermost energy level of an atom

periodic table of the elements

a table in which the element are indicated by their chemical symbols and arranged in order of increasing atomic number

chemical bond

a form of attraction between atoms that holds them together

covalent bond

a bond in which two atoms share a pair of electrons

single bond

a covalent bond in which two atoms share two electrons

double bond

a covalent bond in which two atoms share two pairs of electrons

electronegativity

difference in the ability of atoms to attract electrons

polar covalent bond

a bond that results when electrons are shared unequally between two atoms

nonpolar covalent bond

a bond that results when electrons are shared equally, or nearly equally, between two atoms

ionic bond

a bond in which two ions with opposite electrical charges associate with each other

chemical reaction

a process by which molecules are transformed into different molecules

reactant

atoms or molecules that are changed in a chemical reaction

product

atoms or molecules that are made in a chemical reaction

polymer

a large molecule composed of many smaller subunits

monomer

a single molecule that can bond chemically with similar molecules in a polymer

protein

a type of organic molecule that provides structural support for the cell and speeds up chemical reactions

amino acid

the subunits of proteins

nucleic acid

a type of organic molecule that encodes and transmits genetic information

ribonucleic acid (RNA)

a molecule chemically related to DNA that is synthesized from a DNA template and is involved in protein synthesis, among other functions

nucleotide

a subunit of nucleic acids, consisting of a 5-carbon sugar, a nitrogen-containing base, and one or more phosphate groups

carbonhydrate

a type of organic molecule

lipid

a type of organic molecule that is hydrophobic; make up the barrier between the cell and its environment, store energy, and act as signaling molecules

hydrophobic

water-fearing; describes nonpolar molecules that do not dissolve well in water

hydrophilic

water loving; describes polar molecules that readily dissolve in water

polar

a molecule that has regions of positive and negative charges

hydrogen bond

an interaction between a hydrogen atom with a slight positive charge and an electronegative atom of another molecule

cohesion

tendency of water molecules to stick to one another due to hydrogen bonding with one another

adhesion

the tendency of water molecules to stick to other polar or charged molecules

surface tension

a measure of the difficulty of breaking the surface of a lipid

specific heat

the amount of heat required per unit mass of a substance to raise the temperature of the mass by 1 degree Celsius

solvent

a substance that can dissolve another substance

acid

a molecule that donates H+ ions to a solution

base

a molecule that accepts H+ ions and removes them from solution

pH scale

a measure of the acidity of a solution

Dehydration synthesis reaction

a reaction in which a water molecule is released by the two reacting molecules as a new covalent bond is formed between them

hydrolysis reaction

a reaction that adds water across a covalent bond and breaks the covalent bond