AP Bio - Unit 1: Chemistry of Life

elements

elements

substances that cannot be broken down into simpler substances by chemical means

trace elements

elements that are required by an organism only in very small quantities

atom

building blocks of the physical world

isotopes

atoms that differ in the number of neutrons in the nucleus

radiometric dating

the system of determining the age (of a fossil) by accessing the amount of remaining carbon-14

compound

when two or more elements are combined (held together by ionic, covalent, hydrogen bonds)

chemical reaction

when two or more elements or compounds are combined

ionic bond

a chemical bond where one or more electrons are transferred from one atom to the other

covalent bond

a chemical bond where electrons are shared between atoms

polar covalent: unequally shared electrons

nonpolar covalent: equally shared electrons

hydrogen bond

weak chemical bond that form when a hydrogen atom is covalently bonded to one electronegative atom is also attracted to another electronegative atom

cohesion

the attraction of molecules to other molecules of the same kind

adhesion

the attraction of molecules to different kinds of molecules, substances, or surfaces

surface tension

the property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules

acidic

a solution containing and releasing a lot of hydrogen ions (H+)

basic (alkaline)

a solution containing and releasing a lot of hydroxide ions (OH-)

pH scale

measures acidity or alkalinity of a solution (1-14)

• a change of one pH number represents a tenfold change in hydrogen ion concentration

organic compounds

CHON - carbon, hydrogen, oxygen, nitrogen

inorganic comounds

molecules that do not contain carbon atoms

hydrolysis

water breaking the bond between two monomers

dehydration synthesis

when the water molecule is removed, a larger compound is formed

glucose and fructose

six-carbon sugars C6H12O6

glycosidic linkage

the bond of when two monosaccharides are joined

starch

a type of polysaccharide that stores sugar in plants

glycogen

a type of polysaccharide that stores sugars in animals

cellulose

a polysaccharide that is used in plants’ cell walls and structural support

amino acids

organic molecules that serve as the building blocks of proteins