Chapter 2 Flashcards
Amphipathic
Of a molecule, having both hydrophilic and hydrophobic regions.
Anabolic Reaction
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.
Anion
A negatively charged ion.
Atomic Number
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.
Atom
The smallest unit of a chemical element. Consists of a nucleus and one or more electrons.
Bilayer
A structure that is two layers in thickness. In biology, most often refers to the phospholipid ____ of membranes
Bohr Model
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.
Carbohydrates
Organic compounds containing carbon, hydrogen, and oxygen in the ratio 1:2:1 (i.e., with the general formula Cn(H2O)n). Common examples are sugars, starch, and cellulose.
Catabolic Reaction
A synthetic reaction in which complex molecules are broken down into simpler ones and energy is released.
Cation
An ion with one or more positive charges.
Chemical Bond
An attractive force stably linking two atoms.
Chemical Reaction
The change in the composition or distribution of atoms of a substance with consequent alterations in properties.
Cohesion
The tendency of molecules (or any substances) to stick together.
Condensation Reaction
A chemical reaction in which two molecules become connected by a covalent bond and a molecule of water is released (AH + BOH ? AB + H2O.)
Covalent Bond
Chemical bond based on the sharing of electrons between two atoms
Disaccharide
A carbohydrate made up of two monosaccharides (simple sugars).
Electronegativity
The tendency of an atom to attract electrons when it occurs as part of a compound.
Electron
A subatomic particle outside the nucleus carrying a negative charge and very little mass.
Electron Shell
The region surrounding the atomic nucleus at a fixed energy level in which electrons orbit.
Element
A substance that cannot be converted to simpler substances by ordinary chemical means.
Fatty Acid
A molecule made up of a long nonpolar hydrocarbon chain and a polar carboxyl group. Found in many lipids.
Functional Group
A characteristic combination of atoms that contribute specific properties when attached to larger molecules
Glycerol
A three-carbon alcohol with three hydroxyl groups; a component of phospholipids and triglycerides.
Glycosidic Linkage
Bond between carbohydrate (sugar) molecules through an intervening oxygen atom (—O—).
Heat of Vaporization
The energy that must be supplied to convert a molecule from a liquid to a gas at its boiling point.
Hydrogen Bond
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.
Hydrolysis Reaction
A chemical reaction that breaks a bond by inserting the components of water (AB + H2O ? AH + BOH).
Hydrophilic
Having an affinity for water.
Hydrophobic
Having no affinity for water.
Ion
An electrically charged particle that forms when an atom gains or loses one or more electrons.
Ionic Bond
An electrostatic attraction between positively and negatively charged ions
Laws of Thermodynamics
Laws derived from studies of the physical properties of energy and the ways energy interacts with matter.
Lipid
Nonpolar, hydrophobic molecules that include fats, oils, waxes, steroids, and the phospholipids that make up biological membranes.
Macromolecule
A giant (molecular weight > 1,000) polymeric molecule. Ex: The protein group polysaccharides, and nucleic acids.
Metabolism
The sum total of the chemical reactions that occur in an organism, or some subset of that total
Molecule
A chemical substance made up of two or more atoms joined by covalent bonds or ionic attractions.
Monomer
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).
Monosaccharide
A simple sugar. Oligosaccharides and polysaccharides are made up of monosaccharides.
Neutron
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.
Nucleus
(1) In cells, the centrally located compartment of eukaryotic cells that is bounded by a double membrane and contains the chromosomes. (2) In the brain, an identifiable group of neurons that share common characteristics or functions.
Ogliosacchardie
A polymer containing a small number of monosaccharides.
Phospholipid Bilayer
The basic structural unit of biological membranes; a sheet of phospholipids two molecules thick in which the phospholipids are lined up with their hydrophobic “tails” packed tightly together and their hydrophilic, phosphate-containing “heads” facing outward. Also called lipid bilayer.
Phospholipid
A lipid containing a phosphate group; an important constituent of cellular membranes.
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.
Polymer
A large molecule made up of similar or identical subunits called monomers.
Polysacharide
A macromolecule composed of many monosaccharides (simple sugars). Common examples are cellulose and starch.
Products
The molecules that result from the completion of a chemical reation.
Proton
(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+.
Reactant
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 bonds—that is, all the bonds are saturated with hydrogen atoms.
Triglyceride
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.
