AP Biology Exam Key Words Questions and Answers

AP Biology Exam Key Words Questions and Answers Elements Substances that cannot be broken down into simpler substances by chemical means Oxygen, carbon, hydrogen, nitrogen Four elements most commonly found in organisms Trace Elements (only required in very small quantities) Iron, iodine, copper Atom The smallest unit of an element that retains its characteristic properties Proton Small subatomic particles, located in the nucleus, positively charge particles Electrons Negatively charged, spin outside nucleus Neutron Inside nucleus, uncharged particles Ionic bond Formed between two atoms when one or more electrons are transferred from one atom to the other Covalent bond Formed when electrons are shared between atoms Nonpolar covalent Electrons are shared equally between atoms Polar covalent Electrons are shared unequally Cohesion Water molecules have a strong tendency to stick together Adhesion Water molecules also like to stick to other substances Heat capacity The ability of a substance to store heat