BIO VOCAB CHP 2, 3

Acid

A substance that increases the hydrogen ion concentration of a solution.

Adhesion

The attraction between different kinds of molecules.

Aqueous solution

A solution in which water is the solvent.

Atom

The smallest unit of matter that retains the properties of an element.

Atomic Mass

The total mass of an atom, which is the mass in grams of 1 mole of the atom.AA

Atomic number

The number of protons in the nucleus of an atom, unique for each element and designated by a subscript to the left of the elemental symbol.

Base

A substance that reduces the hydrogen ion concentration of a solution.hC

Chemical equilibrium

In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time.

Chemical reaction

The making and breaking of chemical bonds, leading to changes in the composition of matter.oC

Cohesion

The binding together of like molecules, often by hydrogen bonds.

Compound

A substance consisting of two or more elements

Covalent Bond

A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.

Electron

A subatomic particle with a single negative electrical charge and a mass about 1/2,000 that of a neutron or proton.leE

Electronegativity

The attraction of a given atom for the electrons of a covalent bond.lE

Element

Any substance that cannot be broken down to any other substance by chemical reactions.vE

Evaporative cooling

The process in which the surface of an object becomes cooler during evaporation, owing to a change of the molecules with the greatest kinetic energy from the liquid to the gaseous state.

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.

Ion

An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge.

Ionic Bond

A chemical bond resulting from the attraction between oppositely charged ions.

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.M

Molecular formula

A type of molecular notation representing the quantity of constituent atoms, but not the nature of the bonds that join them.olM

Molecule

Two or more atoms held together by covalent bonds.eutN

Neutron

A subatomic particle having no electrical charge (electrically neutral), with a mass of about 1.7 × 10-24 g, found in the nucleus of an atom.

Nonpolar covalent bond

A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.Hp

pH

A measure of hydrogen ion concentration equal to -log [H+] and ranging in value from 0 to 14.

Polar covalent bond

A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

Product

A material resulting from a chemical reaction.

Proton

A subatomic particle with a single positive electrical charge, with a mass of about 1.7 x 10-24 g, found in the nucleus of an atom.eactR

Reactant

A starting material in a chemical reaction S

Solute

A substance that is dissolved in a solution S

Solution

A liquid that is a homogeneous mixture of two or more substances.

Solvent

The dissolving agent of a solution. Water is the most versatile solvent known.S

Surface tension

A measure of how difficult it is to stretch or break the surface of a liquid. Water has a high surface tension because of the hydrogen bonding of surface molecules.

Valence electron

An electron in the outermost shell

Van der waals interactions

Weak attractions between molecules or parts of molecules that result from localized charge fluctuations.

Alpha helix

A spiral shape constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding.

Amino Acid

An organic molecule possessing both carboxyl and amino groups. serve as the monomers of polypeptides.

Amino Group

A chemical group consisting of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of 1+.

Antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix.

ATP

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

Beta Pleated Sheet

one form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds.

Carbohydrate

A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides)

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 hydroxyl group.

Cellulose

A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by β glycosidic linkages.

Chitin

A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all arthropods.

Cholesterol

A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids, such as hormones.

Dehydration reaction

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

Denaturation

In proteins, a process in which a protein unravels and loses its native shape, thereby becoming biologically inactive; in DNA, the separation of the two strands of the double helix; occurs under extreme (noncellular) conditions of pH, salt concentration, and temperature.

DNA

A double-stranded, helical nucleic acid molecule consisting of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T); capable of replicating and determining the inherited structure of a cell's proteins.

Disaccharide

A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed during dehydration synthesis.

Disulfide Bridge

A strong covalent bond formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer.

Enzyme

A macromolecule serving as a catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction.

Fatty Acid

A long carbon chain carboxylic acid. vary in length and in the number and location of double bonds; linked to a glycerol molecule form a fat molecule, also known as a triacylglycerol or triglyceride.

Functional Group

A specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and usually involved in chemical reactions.

Glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

Hydrocarbon

An organic molecule consisting only of carbon and hydrogen.

Hydrolysis

A chemical process that lyses, or splits, molecules by the addition of water, functioning in disassembly of polymers to monomers.

Hydrophobic interaction

A type of weak chemical bond formed when molecules that do not mix with water coalesce to exclude water.

Hydroxyl Group

A chemical group consisting of an oxygen atom joined to a hydrogen atom. Molecules possessing this group are soluble in water and are called alcohols.

Isomer

One of several compounds with the same molecular formula but different structures and therefore different properties.

Lipid

One of a group of compounds, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.

Macromolecule

A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction. Polysaccharides, proteins, and nucleic acids are examples.

Monomer

The subunit that serves as the building block of a polymer.

Monosaccharide

The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides.

Nucleic Acid

A polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types are DNA and RNA.

Nucleotide

The building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.

Organic chemistry

the study of carbon compounds (organic compounds)

Peptide Bond

The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction.

Phosphate group

A chemical group consisting of a phosphorus atom bonded to four oxygen atoms; important in energy transfer.

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Polynucleotide

A polymer consisting of many nucleotide monomers in a chain; nucleotides can be those of DNA or RNA.

Polysaccharide

A polymer of many monosaccharides, formed by dehydration reactions.

Primary structure

The level of protein structure referring to the specific sequence of amino acids.

Protein

A functional biological molecule consisting of one or more polypeptides folded and coiled into a specific three-dimensional structure.

Quarternary structure

The particular shape of a complex, aggregate protein, defined by the characteristic three-dimensional arrangement of its constituent subunits, each a polypeptide.

RNA

A type of nucleic acid consisting of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis, gene regulation, and as the genome of some viruses.

Saturated fatty acid

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that are attached to the carbon skeleton.

Secondary Structure

The localized, repetitive coiling or folding of the polypeptide backbone of a protein due to hydrogen bond formation between constituents of the backbone.

Starch

A storage polysaccharide in plants, consisting entirely of glucose monomers joined by glycosidic linkages.

Steroid

a type of lipid characterized by a carbon skeleton consisting of four rings with various chemical groups attached.

Tertiary structure

Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.

Trans fat

An unsaturated fat containing one or more trans double bonds.

Triacylglycerol

Three fatty acids linked to one glycerol molecule; also called a fat or a triglyceride.

Unsaturated fatty acid

A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.