Life 102 (003): Attributes of Living SystemsStudy Guide Exam 1DEFINITIONSReductionism: The addition of electrons to a substance involved in a redox reaction.Systems Biology: An approach to studying biology that aims to model the dynamic behavior of whole biological systems.Atom: The smallest unit of matter that retains the properties of an element.Neutron: A subatomic particle having no electrical charge (electrically neutral), with a mass of about 1.7x10^-24g found in the nucleus of an atom.Proton: A subatomic particle with a single positive electrical charge, with a mass of about 1.7x10^-24g, found in the nucleus of an atom.Electron: A subatomic particle with a single negative electrical charge and mass about 1/2000 that of a neutron or proton. One or more electrons move around the nucleus of at atom.Element: Any substance that cannot be broken down to any other substance by chemical reactions.Trace element: An element indispensable for life but required in extremely minuteamounts.Atomic number: The number of protons in the nucleus of an atom, unique for reach element and designated by a subscript to the left of the elemental symbol.Atomic weight: (Atomic mass) The total mass of an atom, which is the mass in grams of 1 mole of the atom.Solute: A substance that is dissolved in a solution.Solvent: The dissolving agent of a solution. Water is the most versatile solvent known.Carboxyl Group: A chemical group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxylgroup.Isotope: One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass.Radioactive isotope: An isotope (an atomic form of a chemical element) that is unstable; the nucleus decays and spontaneously, giving off detectable particles and energy.Hydrophobic interactions: A type of weak chemical bond formed when molecules that do not mix with water coalesce to exclude water.Electronegative: The attraction of a given atom for the electrons of a covalent bond.Covalent bond: A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.Non-polar covalent bond: A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.Polar covalent bond: A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the moreelectronegative atom, making it slightly negative and the other atom slightly positive.Peptide bond: The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration process.Ionic bond: A chemical bond resulting from the attraction between oppositely charged ions.Ion: An atom of group of atoms that has gained or lost one or more electrons, thus acquiring a charge.Hydrogen bond: A type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.Nucleotide: The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.Complementary: (Complementary DNA (cDNA)) A double-stranded DNA molecule made in vitro using mRNA as a template and the enzymes reverse transcriptase and DNA polymerase. A cDNA molecule corresponds to the exons of a gene.Monosaccharide: The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also known as simple sugars, monosaccharides have molecular formulas that are generally some multiple of CH(2)OPhospholipids bilayer: A lipid made up of glycerol joined by two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head. Phospholipids form bilayers that function as biological membranes.Plasmalemma: The liquid matrix of blood in which the cells are suspended.Nucleolus: A specialized structure in the nucleus, consisting of chromatin regions contains ribosomal RNA genes along with ribosomal protein imported from the cytoplasmic site of rRNA synthesis and ribosomal subunit assembly.Phosphorylation: Referring to a molecule that is covalently bonded to a phosphategroup.Peroxisome: An organelle containing enzymes that transfer hydrogen (H(2)) from various substrates to oxygen (O(2)) producing and then degrading hydrogen peroxide.Matter: Anything that takes up space and has mass.Compound: A substance consisting of two or more different elements combined in a fixed ratio.pH: A measure of hydrogen ion concentration equal to –log[H+] and ranging in value from 0 to 14.Buffer: A substance that consists of acid and base forms in a solution and that minimizes changes in pH when extraneous acids or bases are added to the solution.Hydroxyl group: A chemical group that is consisting of an oxygen atom joined to a hydrogen atom. Molecules possessing this group are soluble in water and are called alcohols.Carbonyl group: A chemical group present in aldehyes and ketones and consisting of a carbon atom double-bonded to an oxygen atom.Aldehyde: The carbonyl group at the end of the carbon skeleton.Ketone: The carbonyl group within a carbon skeleton.Molecular Mass/Molar Mass: The sum of the masses of all the atoms in a molecule; sometimes called molecular weight.Daltons: A measure of mass for atoms and sub-atomic particles; the same as the atomic mass unite, or amu.Mass number: The sum of the number of protons and neutrons in an atom’s nucleus.Peptide bond: The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction.Amino group: A chemical group consisting of a nitrogen atom bonded to two hydrogen atoms; can acct as a base in solution, accepting a hydrogen ion and acquiring a charge or 1+.Valence shell: The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.Reactants: A starting material in a chemical reaction.Products: A material resulting from a chemical reaction.Sulfhydral group: A chemical group consisting of a sulfur atom bonded to a hydrogen bond.Phosphate group: A chemical group consisting of a phosphorous atom bonded to four