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chemical reaction

chemical bonds formed between atoms, or exisitng bonds betwen atoms are broken


atoms in the reacting substances on the lef side of the arrow in a chemical formula


rearranged atoms of the reactant to form different substances; on the right side of the arrow of a chemical formula


The sum of all biochemical processes under way within the human body at any moment; includes anabolim and catabolism


using a force to move an object; change in physical structure of matte


ability to do work

kinetic energy

energy of motion; energy that is doing work

potential energy

stored energy; has the potential to do work - either by position or chemical structure

decomposition reaction

breaks a molecule into smaller fragments; AB -> A + B; water molecule broken into hydrogen and oxygen


"water dissolving" one of the bonds is broken in a complex molecule, and the components of a water molecule (H and OH) are added to the resulting products ex: A-B- C-D + H2O --> A-B-C -H + HO - D


"throwing down" decomposition reactions of complex molecules within the body's cells and tisues; a form of potential energy(covalent bond) is broken and kinetic energy is released that can preform work; cells perform vital functions such as growth, movement and reproduction


opposite of decomposition; A + B --> AB; assembles smaller molecules into larger molecules

dehydration synthesis

(condensation) formation of a complex molecule by removing water; ex: A-B-C-H + HO -D ---> A-B-C-D- + H2O


"throwing upward" takes energy to create a chemical bond; synthesis of new molecules within the body's cells; anabolism must be suported by catabolic energy to balance cellular function

exchange reaction

parts of reacting molecules are "shuffled around" to produce new products; AB + CD ---> AD + CB

reversible reactions

chemical reactions are reversible; A + B <-----> AB

activation energy

the amount of energy required to start a reaction


promote chemical reactions by lowering the activation energy requirements; enzymes belong to a class of substances called "catalysts"; all enzymes are proteins; different enzymes are required for different chemical reactions to occur; ex: A+B <-------> (enzyme is represented by arrow) AB


reactions that release energy; the amount of energy released is greater than the activation energy needed to start the reaction; relatively common in the body; responsible for maintaining body temperature by providing the necessary heat


more energy needed to start the reaction than is released as it proceeds the reaction as a whole will absorb energy


essential elements and molecules normally obtained through diet


large group including all the molecules ( nutrients included) that can be brodken down (synthesized) by chemical reactions inside the human body

inorgnic compounds

generally do not contain hydrogen or carbon atoms; carbon dioxide, oxygen, water, inorganic acids, bases and salts

organic compounds

formed by carbon and hydrogen atoms; carbohydrates, lipids, proteins, and nucleic acids


uniformed mixture of two or more substances


medium in which other atoms, ions, and/or molecules disperse; water is the universal solvent


the dispersing substance in the solvent; ex: salt (solute) dissolves in water (solvent)


soluble inorgnic molecules whose ions will conduct an electical current in solution; ex: sodium chloride in blood and other body fluids


"loving water" substances that readily interact with water; ex: glucose


"fear of water" substances that do not readily react with water; ex: oil


solution containing dispersed proteins or other large molecules; ex: jell-o


contains larger moelcules than a colloid; if left undistruded with settle; ex: sand and water


concentration of hydrogen (H+) ions in fluids H+ ions are extremely reactive in solution; change shape of complex molecules; in human body can disrupt cell and tissue function- body fluids must be regulated precisely

pH of a solution

negative logarithm of H+ ion concentration in moles per liter; ex: pH of 6 ([H+] = 1 x 10 -6 or 0.0000001) concentration of H+ ions is 10times as great as it is at a pH of 7


a pH below 7 is acidic; contains more H+ ions than hydroxide ions (OH-)


pH above 7 is basic (alkaline); more OH- ions than H+ ions


ionic compound consisting of any cation except a H+ ion and any anion except OH-; dissolve completely in water ex: sodium chloride NaCl; Na+ and Cl- in solution


stabilize the pH of a solution by removing or replacing H+ ions


organic molecule; contains carbon, hydrogen, and oxygen in a ratio of 1:2:1; C6H12O6 (hexose -carbohydrate -fuel); less than 3% of total body weight


simple sugar; contains 3 to 7 atoms; trios (3-carbon), tetrose (4-carbon) pentose (5-carbon), hexose (6-carbon), or heptose (7-carbon)


the same types and numbers of atoms, but different structures


two monosaccharides joined together; sucrose - dehydration synthesis; breakdown ex of hydrolysis


large molecules form by repeated dehydration synthesis reactions; complex carbohydrates; ex: cellulose, starches formed from glucose molecules (monosaccharide)


animal starch; does not dissolve in water or body fluids; made and stored by muscle cells


fat; carbon, hydrogen and water; 1:2 ratio contain less oxygen than carbohydrates with the same number of carbon atoms; ex: C12H24O2; contain small traces of phorsphorus, nitrogen, or sulfur; fats, oils, and waxes- insuluable in water - body uses transport mechanisms - 12-18% of body weight;

fatty acids

long chains carbon chains with hydrogen atoms attached. carboxylic acid group; the carboxyl end accociates with water molecules-hydrophilic portion; hydrocarbon tail is hydrophobic


lipids derived from arachidonic acid - must be absorbed in the diet; cannot be synthesized by the body


short chained fatty acids- 5 carbon atoms or joined in a ring; released in cells to coordinate/direct local cellular activities; extremely powerful


formed by the attachment to glycerol; dehydration synthesis produces monoglyceride(glycerol plus one fatty acid) diglyceride (glycerol + two fatty acids), triglyceride (gylcerol + three fatty acids)


large lipid molecules; cholesterol found in all animal membranes - use to maintain membrane, growth and division; regulation of sexual funcion(setrogens/testoserone); tissue metabolism/mineral balance (corticosteroids/calcitriol); bile salts ( normal processing of dietary fats


related structurally;cells snthesize both types of lipids; help to form and maintain intracellular structures called membranes


abundant organic components of the human body; contain carbon, hydrogen, oxygen, and nitrogen; perform a variety of essential functions - support, movement, transport, buffering, metabolic regulation, coordination, defense

amino acids

20 different amino acids - typical protein contains 1000 amino acids, large contain 100,000; long chains of organic molecules; 5 components: central carbon atom, hydrogen atom, amino group, carboxylic acid group, a variable group (R group/side chain)

peptide bond

dehydration synthesis linking amino acids; creates a covalent bond between carboxylic acid groupd and one amino acid and teh amino acid of another;


molecules held together by peptide bonds (dipeptide- 2 amino acids)


a chain of amino acids (tripeptides and larger) - polypeptides containing 100 or more minio acids are called proteins

primary structure

sequence of amino acids along the length of a single polypeptide

secondary structure

result of hydrogen bonding along the length of the polypeptide chain; produces a spiral - known as pleated sheet

tertiary structure

coiling and foldiing of a polypeptide

quaternary structure

separate polypeptide subunits interact to form a larger molecule

fibrous proteins

tough, durable, and usually insoluble in water

globular proteins

compact, rounded, readily enter aqueous solution; function only if they remain in solution


reactants in enzymatic reactions

active site

groove/pocket; substrate bonds to this special region of the enzyme


each enzyme catalyzes only one type of reaction


an enzyme that has reached its saturation limit


ion or molecule that must bind to the enzyme before substrates can also bind; without cofactor enzyme is intact but nonfuctional


nonprotein ormganic molecules that function as cofactors


large proteins (glycoproteins) function as enzymes, antibodies, hormones, or proteins - provides lubriication -secrets mucins form mucus lines respiratory/digestive tract; proteoglycans large polysaccharide molecules; tissue fluids - syrupy consistency

nucleic acids

large organic molecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus; store and process info at the molecular level inside cells; two classes: DNA, RNA


deoxyribronucleic acid; determines inherited characteristics - structure and function


ribonucleic acid; manufacture specific forms of proteins using DNA as a template; three forms: rRNA, mRNA, tRNA


subunit containing three components: pentose (5-carbon sugar) either ribose RNA or deoxyribose DNA, phosphate group, and nitrogenous base (adenine (A), guanine (G), cytosine(G), thymine (T) found in paris in DNA (A-T, G-C) and uracel (U) in RNA paris with A (A-U)

High -energy bonds

stored in cells as high-energy compounds ATP (andenosine triphosphate)


adenosine diphosphate - ATP s made by cells when a phosphate group is bonded ADP


the process of adding a phosphate group to ADP to make ATP; cells use the energy released by ATP to power essential activities

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