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Basic unit of matter. Made up of protons, neutrons, and electrons.


Positively charged particles with the same mass as a neutron. Makes up the nucleus with the neutrons.


Neutrally charged particles with the same mass as a proton. Makes up the nucleus with the protons.


Negatively charged particles. Orbits the nucleus.

Covalent Bond

A bond that forms when electrons are shared between atoms.

Ionic Bond

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


The smallest unit of most compounds.

Polar Molecule

When a molecule (water) has an uneven distribution of electrons between the oxygen and hydrogen atoms. (positive and negative charged ends)

Hydrogen Bond

A weak chemical bond formed by the attraction of positively charged hydrogen atoms to other negatively charged atoms


An attraction between molecules of the same substance.


An attraction between molecules of different substances.

Surface Tension

Water's cohesion cause molecules on the surface of water to be drawn inward, which is why drops of water form beads on a smooth surface.

Capillary Action

One of the forces that draw water out of the roots of a plant and up into its stems and leaves.

pH Scale

Indicates the concentration of H+ ions in a solution.


Contains higher concentrations of H+ ions than pure water and have pH values below 7.


Contains lower concentrations of H+ ions than pure water and have pH values above 7.


Has a pH of exactly 7.


Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH.


Large molecules that are formed by joining smaller organic molecules together.


Have four valence electrons. Can bond with many elements. Can bond with itself.

Four Bond

Carbon atoms have four valence electrons. Each electron can join with an electron from another atom to for a strong covalent bond.


The smaller units that join together with polymers to create macromolecules.


The larger units that join together with monomers to create macromolecules.


Compounds made up of carbon, hydrogen, and oxygen atoms with a ratio of 1:2:1. Used as the main source of energy and for structural purposes in living things. (Quick energy)


The monomer of carbohydrates.


The polymer of carbohydrates.

Benedict's Solution

Tests for simple sugars (carbohydrates)

Iodine Solution

Tests for starch (carbohydrates)


Made mostly from carbon and hydrogen atoms. Common categories are fats, oils, and waxes. Used to store energy, in important parts of biological membranes, and for waterproof coverings.


Combines with fatty acids to form lipids.

Fatty Acids

When combined with Glycerol, lipids are formed.


Fats with the maximum number of hydrogens.


Fatty acids that contain more than one double bond.

Sudan 4

Tests for lipids.


Made mostly of nitrogen as well as carbon, hydrogen, and oxygen. Used for structure and support, help to fight disease, carry out cell functions, and form bones and muscles.

Amino Acids

Linked by peptide bonds are the monomers of proteins.


Proteins that speed up (catalyze) chemical reactions that take place in cells and lower activation energy. Temperature and pH affect how well it works.


The reactants of enzyme-catalyzed reactions.

Active Site

The place where substrates bind to the enzyme.


Tests for proteins.

Nucleic Acids

Made mostly of hydrogen, oxygen, nitrogen, carbon, and phosphorus. Used to store and transmit hereditary, or genetic, information.


Consist of three parts: a 5 - carbon sugar, a phosphate group, and a nitrogen base. Monomer of Nucleic Acids


Sugar ribonucleic acid. One kind of nucleic acid.


Sugar deoxyribonucleic acid. One kind of nucleic acid.

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