AP Biology - The Chemistry of Life Exam Study Guide.

AP Biology - The Chemistry of Life Exam Study Guide. Elements - answersubstances that cannot be broken down into simpler substances by chemical means CHNOPS - answeran acronym representing the 6 key elements of life carbon - answerkey element of life; major component of ALL organic compounds, including all 4 types of macromolecules (sugars, fats, proteins, and nucleic acids); rarely found unbound to other elements hydrogen - answerkey element of life, highly involved in the creation of protein gradients that enable photosynthesis and respiration nitrogen - answerkey element of life, especially prevalent in proteins and nucleic acids; wastes based on excesses of this element must be excreted by organisms to prevent the accumulation of toxic ammonia in cells oxygen - answerkey element of life, involved in processes like oxidative phosphorylation and a major component of many organic compounds; exists in the atmosphere in molecular form, small enough to permeate most membranes by simple diffusion phosphorous - answerkey element of life; especially important for its role in phosphate and thus in ATP molecules, which store energy to fuel the majority of cellular work sulfur - answerkey element of life; especially important in proteins, where disulfide bridges composed of this element help anchor peptide chains into functional shapes (tertiary structure) trace elements - answerelements that are required by organisms in only very small quantities, such as Fe, Cu, I, etc atom - answerthe smallest unit of an element that retains its characteristic properties; composed of subatomic particles such as protons, neutrons, and electrons nucleus - answerthe center core of an atom where the protons and neutrons are concentrated protons - answerpositively charged subatomic particles located in the nucleus of an atom; constant for all atoms of the same element neutrons - answersubatomic particles that carry no charge; located in the nucleus of an atom; number can vary among atoms of the same element, leading to various isotopes (some of which are unstable, or radioactive, and spontaneously split due to instability) isotopes - answeratoms of the same element that have different numbers of neutrons and thus different atomic masses; some are unstable, or radioactive electrons - answernegatively charged subatomic particles that orbit the nucleus of an atom in a region of space called the "electron cloud" valence electrons - answerthe electrons of the outermost energy level of an atom that determine bonding characteristics valence - answerthe maximum number of bonds that an atom of a particular element can form; based on the number of valence electrons (8 - ve) atomic number - answerthe number of protons in all atoms of a specific element mass number - answerthe weighted average of the masses of the different isotopes of an element atomic mass - answerthe mass of an atom of a particular isotope of a particular element; equal to the number of protons plus the number of neutrons compound - answera combination of two or more different types of atoms in a fixed ratio chemical reaction - answerthe formation or destruction of chemical bonds between two or more atoms or compounds chemical bond - answerforces that hold the atoms of a compound together, including ionic bonds, covalent bonds, hydrogen bonds, etc ionic bond - answerchemical bond formed when an electron is transferred from one atom to another, creating a positive ion and a negative ion, which are then attracted to one another by electromagnetic forces formula unit - answertwo or more ions (monoatomic or polyatomic) held together by ionic bonds covalent bond - answerchemical bond formed when an electron pair is shared between two atoms, contributing to the outer shell of electrons of both molecule - answertwo or more atoms held together by chemical bonds nonpolar covalent bond - answercovalent bond where the electron pair is shared equally between both atoms with the same or similar electronegativities