click below
click below
Normal Size Small Size show me how
Chapter Two Terms
Chemistry of Life
Question | Answer |
---|---|
acid | any substance that, when dissolved in water, contributes to an excess of H- ions (that is, a low pH) |
alkaline | base; any substance that, when dissolved in water, contributes to an excess of OH- ions (thus creating a high pH) |
aqueous solution | liquid mixture in which water is the solvent; for example, saltwater is an aqueous solution because water is the solvent |
atom | smallest particle of a pure substance (element) that still has the chemical properties of that substance; composed of protons, electrons, and neutrons (subatomic particles) |
atomic mass | combined total number of protons and neutrons in an atom |
atomic number | total number of protons in an atom's nucleus; atoms of each element have a characteristic atomic number |
base | 1. A chemical that, when dissolved in water, reduces the relative concentration of H+ ions in the whole solution (sometimes by adding OH- ions) |
base | 2. In the context of nucleic acids, base or nitrogen base refers to one part of a nucleotide (sugar, phosphate, and base) that is the basic building block of nucleic acid molecules; possible bases include adenine, thymine, guanine, cytosine, and uracil. |
carbohydrate | organic compounds containing carbon, hydrogen and oxygen in certain specific proportions (C, H, O in a 1:2:1 ratio); for example, sugars, starches, and cellulose |
compound | substance whose molecules have more than one kind of element in them |
covalent | chemical bond formed when atoms share electrons by overlapping their energy levels (electron shells) |
dehydration | excessive loss of body water; the most common fluid imbalance; an abnormally low volume of one or more body fluids |
dissociation | separation of ions as they dissolve in water |
double helix | shape of DNA molecules; a double spiral |
electrolyte | substance that ionizes (dissociates to form ions) in solution, rendering the solution capable of conducting an electric current |
electron | negatively charged particle orbiting the nucleus of an atom |
element | pure substance, composed of only one type of atom |
energy level | limited region surrounding the nucleus of an atom at a certain distance containing electrons; also called a shell |
enzyme | a functional protein acting as a biochemical catalyst allowing chemical reactions to take place in a suitable time frame |
glycogen | polysaccharide made up of a chain of glucose (monosaccharide) molecules; animal starch |
hydrolysis | chemical reaction in which water is added to a large molecule causing it to break apart into smaller molecules |
inorganic compound | compound whose molecules do not contain carbon-carbon or carbon-hydrogen bonds |
ionic bond | chemical bond formed by the positive-negative attraction between two ions |
lipid | organic molecule usually composed of glycerol and fatty acid units; types include triglycerides, phospholipids, and cholesterol; a fat, wax, or oil |
matter | any substance that occupies space and has mass |
molecule | particle of matter composed of one or more smaller units called atoms |
neutron | electrically neutral particle withing the nucleus of an atom |
nucleic acid | the two nucleic acids are ribonucleic acid, found in the cytoplasm, and deoxyribonucleic acid, found in the nucleus; made up of units called nucleotides that each include a phosphate, a five-carbon sugar, and a nitrogen base |
nucleus | spherical structure within a cell; a group of neuron cell bodies in the brain or spinal cord; central core of the atom, made up of protons and (sometimes) neutrons |
organic compound | compound whose large molecules contain carbon and that include C-C bonds and/or C-H bonds |
peptide bond | covalent bond linking amino acids within a protein molecule |
pH | mathematical expression of relative H+ concentration (acidity); pH value higher than 7 is basic, pH value less than 7 is acidic, pH value equal to 7 is neutral |
product | in any kind of synthesis reaction, the reactants combined to form a larger product, e.g., K+ + Cl- ---->KCl |
protein | one of the basic nutrients needed by the body; a nitrogen-containing organic compound composed of a folded strand of amino acids |
proton | positively charged particle within the nucleus of an atom |
reactant | any substance entering (and being changed by) a chemical reaction |
solute | substance that dissolves into another substance; for example, in saltwater the salt is the solute dissolved in water |
solvent | substance in which other substances are dissolved; for example, in saltwater the water is the solvent for salt |