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Basic vocabulary for beginning Biology Students


The basic unit of matter.


subatomic particle with positive charge found in the nucleus of an atom


subatomic particle with no charge (neutral) found in the nucleus of an atom


subatomic particle with negative charge found in energy levels outside the nucleus

valence electrons

electrons found in the outermost energy level that are involved with bonding


pure substance, consisting of only 1 type of atom (like sodium)


substance formed from the chemical combination of two or more elements in definite proportions


atoms of the same element with different numbers of neutrons


charged atom formed when atom either loses electron(s) (and becomes + charged) or gains electron(s) becoming negatively charged

ionic bonds

involve a transfer of electrons and produces ions. Happens only between metals and nonmetals

covalent bonds

electrons are shared between atoms. Occurs between two nonmetals or in diatomic molecules.

chemical reaction

process by which atoms or groups of atoms in substances are reorganized into different substances

chemical equation

chemical formulas and symbols describe the substances in the reaction and arrows indicate the process of change


starting substances in a chemical reaction found on the left side of the (arrow) equation


substances formed during the reaction and found on the right side of the (arrow) chemical equation

activation energy

the minimum amount of energy needed for reactants to form products in a chemical reaction


a special type of protein called a catalyst because it speeds up a chemical reactions in cells by lowering the activation energy


the item that the enzyme catalyzes

active site

the spot on the substrate where the enzyme "fits" or bonds; enzymes are specific and act like a lock in a key fitting into the active site on the substrate


the uneven distribution of electrons between atoms in a covalent bond; water is polar- the hydrogen end is slightly positive and the oxygen end is slightly negative


molecules of water are attracted to each other due to the polarity of the water molecule/example: surface tension of water


when water molecules are attracted to molecules of other substances/example: water on the sides of a graduated cylinder or capillary action


two or more elements or compounds that are physically mixed together, but not chmically combined and they can be separated physically


homogeneous mixture/ the same throughout examples koolaid, saltwater


substance being dissolved like salt in salt water usually the smaller amount


substance that dissolves usually the larger amount like water in saltwater in fact water is called the universal solvent because it can dissolve so many things


substance that releases hydrogen ions in solution/they measure below 7 on pH scale/ the lower the pH, the stronger the acid


substance that releases hydroxide ions in solution/ pH above 7 higher the number the stronger the base

pH scale

indicates the concentration of H+ ions in a solution 7 is neutral, above 7 is basic, below is acidic


composition: carbon, hydrogen and oxygen
function:main source of (immediate) energy and used for structural purposes


sugars (saccharides) and starches also known as monosaccharides, disaccharides, polysaccharides


examples: steroids, fats, oils, and waxes
composition mostly carbon and hydrogen
function: to store energy and waterproof coverings

nucleic acids

examples: DNA & RNA
function: to store and transmit genetic information


examples: enzymes
function: somes control the rate of reactions and regulate cell processes; some used to form bones and muscles; others transport substances into or out of cells or help fight disease

building blocks (monomers) of proteins

amino acids

building blocks of nucleic acids


building blocks of carbohydrates

monosaccharides (simple sugars) glucose

Substance with pH of 6 would be a


substance with a pH of 7.5 would be

slightly basic

the atomic number tells you....

the number of protons an atom has and if the atom isn't charged (not an ion) also the number of electrons

How do you find the number of neutrons in an atom?

mass number - atomic number

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