A & P Chapter 2

A substance that releases hydrogen ions when in solution (compare with Base); a proton donor

Acid

State of abnormally high hydrogen concentration in the extracellular fluid

Acidosis

The amount of energy required to push a reactant to the level necessary for action

Activation Energy

Region on the surface of a functional (globular) protein where it binds and interacts chemically with other molecules of complementary shape and chage.

Active Site

One of the two major purines found in both RNA and DNA; also found in various free nucleotides of importance to the body, such as ATP

Adenine (A)

State of abnormally low hydrogen ion concentration in the extracellular fluid

Alkalosis

The most common type of secondary structure of the amino acids in proteins; resembles the coils of a telephone cord

Alpha–helix

Organic Compound containing nitrogen, carbon, hydrogen, and oxygen; building block of protein.

Amino Acid

Common waste product of protein breakdown in the body; a colorless volatile gas, very soluble in water and capable of forming a weak base; a proton acceptor

Ammonia (NH3)

An ion carrying one or more negative charges and therefore attracted to a positive pole

Anion

The protein portion of an enzyme.

Apoenzyme

Smallest particle of an elemental substance that exhibits the properties of that element; composed of protons, neutrons, and electrons

Atom

The number of protons in an atom

Atomic Number

The one– or two–letter symbol used to indicate an element; usually the first two letter(s) of the element's name

Atomic Symbol

The average of the mass numbers of all the isotopes of an element

Atomic Weight

Organic molecule that stores and releases chemical energy for use in body cells

ATP (Adenosine Triphosphate)

The number of molecules in one mole of any substance; 6.02x10 to the 23rd

Avagadro's Number

A substance capable of binding with hydrogen ions; a proton acceptor

Base

Chemical substance or system that minimizes changes in pH by releasing or binding hydrogen ions

Buffer

Organic compound composed of carbon, hydrogen, and oxygenl includes starches, sugars, and cellulose

Carbohydrate

Substance that increases the rate of a chemical reaction without itself becoming chemically changed or part of the product

Catalyst

An ion with a positive charge

Cation

A fibrous carbohydrate that is the main structural component of plant tissue

Cellulose

An energy relationship holding atms together; involves the interaction of electrons

Chemical Bond

Energy stored in the bonds of chemical substances

Chemical Energy

A state of apparent repose created by two reactions proceeding in opposite directions at equal speed

Chemical Equilibrium

Process in which molecules are formed, changed, or broken down

Chemical Reaction

Nonprotein substance associated with and activating enzyme, typically a vitamin

Coenzyme

Metal ion or organic molecule that is required for enzyme activity

Cofactor

(1) A mixture in which the solute particles (usually proteins) do not settle out readily. (2) Substance in the thyroid gland containing thyroglobunin protein.

Colloid

Chemical reaction in which larger, more complex atoms or molecules are formed from simpler ones.

Combination (synthesis) reaction

Refers to how a given nitrogenous base of DNA or RNA bonds to another nitrogenous base.

Complentary Base

Substance composed of two or more different elements, the atoms of which are chemically united

Compound

Chemical bond created by eletron sharing between atoms

Covalent bond

Nitrogen–containing base that is a part of a nucleotide structure

Cytosine (C)

Chemical reaction in which a molecule is broken down into smaller molecules or its constituent atoms.

Decomposition Reaction

Process by which a large molecule is synthesized by removing water and covalently bonding smaller molecules together.

Dehydration Synthesis

A combination of two amino acids united by means of a peptide bond.

Dipeptide

Nonsymmetrical molecules that contain electrically unbalanced atoms

Dipole (polar molecule)

Literally, double sugar; e.g., sucrose, lactose

Disaccharide

Chemical reaction in which bonds are both made and brooken; atoms become combined with different atoms.

Displacement (Exchange) reaction

A nucleic acid found in a all living cells; it carries the organism's hereditary information.

DNA

The secondary structure assumed by two strands of DNA, held together throughout their length by H bonds between bases on opposite strands.

Double helix

Regions of space that consecutively surround the nucleus of an atom

Electon shells (Energy shells)

Energy formed by the movement of charged particles across cell membranes

Electrical Energy

Negatively charged subatomic particle; orbits the atom's nucleus

Electron

One of a limited number of unique varieties of matter that composes substances of all kinds; e.g., carbon, hydrogen, oxygen

Element

Chemical reaction that absorbs energy, e.g., an anabolic reaction

Endergonic reaction

The capacity to do work; may be stored (potential) or in action (kinetic).

Energy

A protein that acts as a biological catalyst to speed up chemical reaction

Enzyme

Chemical reaction in which bonds are both made and broken; atoms become combined with different atoms.

Exchange (displacement) reaction

Chemical reaction that releases energy, e.g., a catabolic or oxidative reaction

Exergonic Reaction

Linear chain of carbon and hydrogen atoms (hydrocarbon chains) with an organic acid group at one end. Constituent of a fat.

Fatty Acid

A modified simple sugar (a sugar alcohol); a building block of fats

Glycerol

Main carbohydrate stored in animal cells; a polysaccharide

Glycogen

One of two major purines occurring in all nucleic acids

Guanine (G)

Weak bond in which a hydrogen atom forms a bridge between electron–hungry atoms. An important intramolecular bond.

Hydrogen Bond

A hydrogen atom minus its electron and therefore carrying a positive charge (i.e. a proton)

Hydrogen Ion (H+)

Process in which water is used to split a substance into smaller particles.

Hydrolysis

An ion liberated when a hydroxide (a common inorganic base) is dissolved in water.

Hydroxyl ion (OH–)

Chemical substances that do not contain carbon including water, salts, and many acids and bases.

Inorganic Compound

Atom with a positive or negative charge

Ion

Chemical bond formed by electron transfer between atoms

Ionic bond

One of two or more substances that has the same molecular formula but with its atoms arranged differently

Isomer

Different atomic forms of the same element, vary only in the number of neutrons they contain; the heavier species tend to be radioactive.

Isotopes

Excess levels of ketone bodies in blood. Called ketoacidosis if blood pH is low

Ketosis

The energy of motion or movement, e.g., the constant movement of atoms, or the push given to a swinging door that sets it in motion.

Kinetic Energy

Organic compound formed of carbon, hydrogen, and oxygenl examples are fats and cholesterol.

Lipid

Large, complex molecules containing from 100 to over 10,000 subunits

Macromolecules

Sum of the number of protons and neutrons in the nucleus of an atom

Mass Number

The energy directly involved in moving matter, e.g., Bicycle riding

Mechanical Energy

A way ot express the concentration of a solution; moles per liter of solution

Molarity

A _______ of any element or compound is equal to its atomic weight or its molecular weight (sum or atomc weights) measured in grams

Mole

Particle consisting of two or more atoms joined together by chemical bonds

Molecule

Consist of fatty acid chains and glycerol; also called triglycerides or triacylglycerols. Commonly known as oils when liquid.

Neutral Fats

Displacement reaction in which mixing an acid and a base forms water and a salt.

Neutralization reation

Uncharged subatomic particle; found in the atomic nucleus

Neutron

Electrically balanced molecules

Nonpolar molecules

Class of organic molecules that includes DNA and RNA

Nucleic Acid

Building block of nucleic acids; consists of a sugar, a nitrogen–containing base, and a phosphate group.

Nucleotide

The tendency of atoms to interact in such a way that they have eight electons in their valence shell.

Octet Rule (Rule of Eights)

Pertaining to carbon containing molecules, such as proteins, fats, and carbohydrates.

Organic

Any compound composed of atoms (some of which are carbon) held together by covalent (shared electron)bonds

Organic Compound

Process of substances combining with oxygen or the removal or hydrogen

Oxidation

A reaction that couples the oxidation (loss of electrons) of one substance with the reduction (gain of electrons) of another substance

Oxidation–reduction (Redox) reaction

Bond joining the amine group of one amino acid carboxyl group of a second amino acid with the loss of a water molecule

Peptide Bond

The measure of the relative acidity or alkalinity of a solution

pH Unit

Modified lipid, contains phosphorus

Phospholipid

Nonsymmetrical molecules that contain electrically unbalanced atoms

Polar Molecules

A substance of high molecular weight with long, chainlike molecules consisting of many similar (repeated) units.

Polymer

A chain of amino acids

Polypeptide

Literally, many sugars; a polmer of linked monosaccharides; starch, glycogen.

Polysaccharide

Stored or inactive energy

Potential Energy

Complex substance containing carbon, oxygen, hydrogen, and nitrogen; composes 10–30% of cell mass

Protein

Subatomic particle that bears a positive charge; located in the atomic nucleus

Proton

A substance that takes up hydrogen ions in detectable amounts. Commonly referred to as a base.

Proton Acceptor

A substance that releases hydrogen ions in detectable amounts; an acid

Proton Donor

The process of spontaneous decay seen in some of the heavier isotopes, during which particles or energy is emitted from the atomic nucleus; results in the atom becoming more stable

Radioactivity

Isotope that exhibits radioactive behavior

Radioisotope

A substance taking part in a chemical reaction

Reactant