Chapter 2: The Chemistry and Energy of Life
Terms in this set (63)
Binding of one substance or structure to another, as in a cell binding to its extracellular matrix.
Of a molecule, having both hydrophilic and hydrophobic regions.
A synthetic reaction in which simple molecules are linked to form more complex ones; requires an input of energy and captures it in the chemical bonds that are formed. (Contrast with catabolic reaction.)
A negatively charged ion. (Contrast with cation.)
The smallest unit of a chemical element. Consists of a nucleus and one or more electrons.
The number of protons in the nucleus of an atom; also equals the number of electrons around the neutral atom. Determines the chemical properties of the atom.
A structure that is two layers in thickness. In biology, most often refers to the phospholipid bilayer of membranes. (See phospholipid bilayer.)
A model for atomic structure that depicts the atom as largely empty space, with a central nucleus surrounded by electrons in orbits, or electron shells, at various distances from the nucleus.
Organic compounds containing carbon, hydrogen, and oxygen in the ratio 1:2:1 (i.e., with the general formula CnH2nOn). Common examples are sugars, starch, and cellulose.
A synthetic reaction in which complex molecules are broken down into simpler ones and energy is released. (Contrast with anabolic reaction.)
An ion with one or more positive charges. (Contrast with anion.)
An attractive force stably linking two atoms.
The change in the composition or distribution of atoms of a substance with consequent alterations in properties.
The tendency of molecules (or any substances) to stick together.
A chemical reaction in which two molecules become connected by a covalent bond and a molecule of water is released (AH + BOH â†' AB + H2O.) (Contrast with hydrolysis reaction.)
Chemical bond based on the sharing of electrons between two atoms.
A carbohydrate made up of two monosaccharides (simple sugars).
A subatomic particle outside the nucleus carrying a negative charge and very little mass.
The tendency of an atom to attract electrons when it occurs as part of a compound.
The region surrounding the atomic nucleus at a fixed energy level in which electrons orbit.
A substance that cannot be converted to simpler substances by ordinary chemical means.
A measure of the degree of disorder in any system. Spontaneous reactions in a closed system are always accompanied by an increase in entropy.
A molecule made up of a long nonpolar hydrocarbon chain and a polar carboxyl group. Found in many lipids.
A characteristic combination of atoms that contribute specific properties when attached to larger molecules.
A three-carbon alcohol with three hydroxyl groups; a component of phospholipids and triglycerides.
Bond between carbohydrate (sugar) molecules through an intervening oxygen atom (â€"Oâ€").
The ratio of energy absorbed by a substance the increase in temperature of that substance.
heat of vaporization
The energy that must be supplied to convert a molecule from a liquid to a gas at its boiling point.
A weak electrostatic bond which arises from the attraction between the slight positive charge on a hydrogen atom and a slight negative charge on a nearby oxygen or nitrogen atom.
A chemical reaction that breaks a bond by inserting the components of water (AB + H2O â†' AH + BOH). (Contrast with condensation reaction.)
Having an affinity for water. (Contrast with hydrophobic.)
Having no affinity for water. Uncharged and nonpolar groups of atoms are hydrophobic. (Contrast with hydrophilic.)
An electrically charged particle that forms when an atom gains or loses one or more electrons.
An electrostatic attraction between positively and negatively ions.
Isotopes of a given chemical element have the same number of protons in their nuclei (and thus are in the same position on the periodic table), but differ in the number of neutrons.
The energy associated with movement. (Contrast with potential energy.)
laws of thermodynamics
Laws derived from studies of the physical properties of energy and the ways energy interacts with matter. (See also second law of thermodynamics.)
Nonpolar, hydrophobic molecules that include fats, oils, waxes, steroids, and the phospholipids that make up biological membranes.
A giant (molecular weight > 1,000) polymeric molecule. The macromolecules are the proteins, polysaccharides, and nucleic acids.
The sum of the number of protons and neutrons in an atomâ€™s nucleus.
The sum total of the chemical reactions that occur in an organism, or some subset of that total (as in respiratory metabolism).
A chemical substance made up of two or more atoms joined by covalent bonds or ionic attractions.
A small molecule, two or more of which can be combined to form oligomers (consisting of a few monomers) or polymers (consisting of many monomers).
A simple sugar. Oligosaccharides and polysaccharides are made up of monosaccharides.
One of the three fundamental particles of matter (along with protons and electrons), with mass slightly larger than that of a proton and no electrical charge.
In cells, the centrally located compartment of eukaryotic cells that is bounded by a double membrane and contains the chromosomes.
Description of processes that atoms undergo whereby they obtain, give up or share electrons such that their outer (valence) shell contains eight electrons.
A polymer containing a small number of monosaccharides.
A lipid containing a phosphate group; an important constituent of cellular membranes. (See lipid.)
The basic structural unit of biological membranes; a sheet of phospholipids two molecules thick in which the phospholipids are lined up with their hydrophobic â€œtailsâ€ packed tightly together and their hydrophilic, phosphate-containing â€œheadsâ€ facing outward. Also called lipid bilayer.
polar covalent bond
A covalent bond in which the electrons are drawn to one nucleus more than the other, resulting in an unequal distribution of charge.
A large molecule made up of similar or identical subunits called monomers. (Contrast with monomer.)
A macromolecule composed of many monosaccharides (simple sugars). Common examples are cellulose and starch.
Energy not doing work, such as the energy stored in chemical bonds. (Contrast with kinetic energy.)
The molecules that result from the completion of a chemical reaction.
(1) A subatomic particle with a single positive charge. The number of protons in the nucleus of an atom determine its element. (2) A hydrogen ion, H+.
A chemical substance that enters into a chemical reaction with another substance.
saturated fatty acid
A fatty acid in which all the bonds between carbon atoms in the hydrocarbon chain are single bondsâ€"that is, all the bonds are saturated with hydrogen atoms. (Contrast with unsaturated fatty acid.)
Liquid in which a substance (solute) is dissolved to form a solution.
The attractive intermolecular forces at the surface of liquid; an especially important property of water.
A simple lipid in which three fatty acids are combined with one molecule of glycerol.
unsaturated fatty acid
A fatty acid whose hydrocarbon chain contains one or more double bonds. (Contrast with saturated fatty acid.)
van der Waals interactions
Weak attractions between atoms resulting from the interaction of the electrons of one atom with the nucleus of another. This type of attraction is about one-fourth as strong as a hydrogen bond.