acrylamide: Acrylamide is polymerized to create the gel matrix in this technique. The chemical formula for acrylamide is CH2CHCONH2. In its unpolymerized form, acrylamide is a neurotoxin, and should be handled with care.

adventitia: (a.k.a. tunica adventitia) is the strong outer covering of arteries and veins. It is composed of connective tissue as well as collagen and elastic fibers. These fibers allow the arteries and veins to stretch to prevent overexpansion due to the pressure that is exerted on the walls by blood flow.

ammonium persulfate: In the SDS PAGE technique, this accelerates polymer formation in the reaction to polymerize acrylamide monomers. This chemical provides a source of free radicals to drive the polymerization reaction.

antibody: a protein that is produced by the immune system as part of the immune response to a foreign substance known as an antigen. Antibodies have the property that they may specifically bind to the foreign substance that created the immune response

anti-oxidant: a substance that inhibits oxidation reactions from occurring. Oxidation reactions involve the transfer of electrons from one chemical substance (the oxidizer or oxidizing agent) to another chemical substance.

aorta: The largest artery in the body which has its origin at the heart. It supplies oxygenated blood to the extremities, neck and major organs.

aseptic: free of microbial infection. (for details on precautions to take to ensure an aseptic environment, see the Aseptic Technique [new window] section of Tissue Engineering module)

assay: an analytical test or procedure to characterize or quantify some aspect of a chemical, material or other substance.

beta-mercaptoethanol: a reducing agent with the chemical formula HSCH2CH2OH. In the SDS PAGE experiment, beta-mercaptoethanol acts to break disulfide bonds between cysteine molecules.

blastocyst: a stage of development after the 32 cell morula. A blastocyst has a fluid-filled cavity with lining cells.

bioreactor: a culture vessel for large-scale production of cells or tissue culture.

blocking solution: NEED DEFINITIION

buffer: In chemistry, a buffer refers to a solution that has the capacity to maintain a stable pH, when mixed with a small amount of a substance (such as an acid or base) that would normally alter the pH of a solution

cell culture: cells taken from a living organism and grown under controlled conditions ("in culture"). Also refers to the methods used to maintain cell lines.

cell monolayer: a single, homogenous layer of cells.

cell lysate: a mixture of cell components created by rupturing of the cell wall in a quantity of cells.

collagen: one or all of a family of fibrous proteins of high tensile strength found throughout vertebrates, most abundant protein in mammals, major element of skin, bone, cartilage, teeth, blood vessels, etc.

collagenase: used to disaggregate tissue into individual cells. This substance consists of enzymes that are capable of breaking the peptide bonds of the fibrous collagen protein.

confluence: the state in which cells have grown to maximum capacity within a certain amount of space. At this point surface to surface contact with other cells cause them to inhibit growth.

connective tissue: tissues composed primarily of fibrous proteins such as collagen and containing few cells. Their primary function is to bind together and support various body structures.

contact inhibition: inhibition of cell growth once cells are in complete contact with one another, as in a confluent culture.

continous cell line: cell line or strain having the capacity for infinite survival. Often referred to as an "immortal" cell line.

crosslinked: NEED DEFINITION

cysteine: an amino acid found in proteins that has sulfur as one of its constituent atoms.

denature: to eliminate secondary and higher order structure from a molecule. In the SDS PAGE experiment, proteins are denatured using chemical compounds such as SDS (Sodium Dodecyl Sulfate) and 2-mercaptoethanol.

disulfide bond: a bond between two sulfur atoms. In the context of a protein molecule, this type of bond often forms between two sulfur atoms contained in cysteine molecules located in the amino acid sequence that makes up the protein.

dye front: In the SDS PAGE experiment, this is the horizontal line that the blue dye in the sample buffer makes as it travels through the gel during electrophoresis. The dye front provides a visible indication of progress during electrophoresis, and helps determine if the run has gone on long enough.

electrode: a conductor used to pass current to and from typically non-metallic substances such as tissue, solutions, and so forth.

ectoderm: the outer germ layer of the embryo which gives rise to the epithelium of the skin.

electrophoresis: refers to the process of using an electric field to move molecules in a solution. In the SDS PAGE experiment, these molecules are protein molecules in solution with SDS. For the molecules to be influenced by the electric field, they must have a net charge.

endoderm: the innermost germ layer of the embryo, giving rise to epithelial components of organs such as the gut, liver and lungs.

endothelium: consists of simple squamous epithelium that lines the lumen of all blood vessels. It plays a critical role in the mechanics of blood flow, the regulation of coagulation, leukocyte adhesion, and vascular smooth muscle cell growth, and also serves as a barrier to the transvascular diffusion of liquids and solutes.

fertilization: the union of the male sperm with the female egg (both haploid cells) to produce a diploid cell, the zygote, which then develops to form a new organism.

gastrulation: during embryonic development of most animals a complex and coordinated series of cellular movements occurs at the end of cleavage. In humans, gastrulation results in the formation of the three primary germ layers, ectoderm, mesoderm and endoderm.

hemacytometer : a glass slide with a tiny grid etched onto the surface; for use in counting cells.

immunoblotting: more general term for the Western Blotting technique (see Western Blotting definition).

intima: see tunica intima.

inverted microscope: Unlike a standard microscope, this one has the light on top and the objective lenses under the stage. With this type, you can put a large object like a petri dish on the stage and easily move it around without the lenses getting in the way. The advantage of the inverted microscope is that gravity works in your favor. If your sample is something that will settle, the settling will occur towards the objective on the inverted microscope, but away on the upright microscope. Thus settling objects are easier to see on the inverted microscope

in vitro: literally means "in glass," but mostly used to indicate the artificial environment that culture cells are grown in.

in vivo: the environment found in a living animal.

laminar flow: the flow of a fluid or gas that follows the streamlined surface without turbulence.

linear separation range: In the context of SDS PAGE, the linear separation range refers to the range of molecular weights that exhibit a linear relationship between migration distance (vertically down the gel) and molecular weight. This is the useful range for a given percent polyacrylamide gel, and the analyst's molecules of interest should fall within this range.

matrix: the immediate physical environment in which a process or reaction occurs. In the SDS PAGE experiment, the matrix is the polyacrylamide gel which contains linked chains of polyacrylamide and other reagents such as buffers and Sodium Dodecyl Sulfate.

media: (in blood vessels see tunica media ). A (usually sterile) preparation made for the growth, storage, maintenance, or transport of microorganisms or other cells.

mesoderm: the mddle of three germ cell layers of the embryo or inner cell mass that gives rise to the cardiovascular system, reproductive system, muscles and ligaments

mini-gel: refers to smaller scale (relative to older gel casting and running apparatus) gel equipment for casting and running of gels.

molecular weight: the mass of a single molecule of a given compound. In the case of large molecules, it is usually expressed in kiloDaltons (kD). In the case of significantly smaller molecules, it is expressed in atomic mass units.

molecular weight standard: NEED DEFINITION

monolayer: see cell monolayer

monomer: a molecule that may be linked to form long chains composed of many copies of itself.

morula: a molecule that may be linked to form long chains composed of many copies of itself.

nitrocellulose membrane: NEED DEFINITION

oocyte: the developing female gamete before completion and release. The female germ cells in stages between the prophase of the first maturation division and the completion of the second maturation division.

oxidation reaction: a reaction where electrons are transferred from a chemical called an oxidizing agent, to another chemical compound.

oxidation/reduction reaction: a reaction where a transfer of electrons occurs between two chemical species, i.e. where one is reduced an another is oxidized.

passaging: see subculture.

pH: a measure of the hydrogen ion concentration in a solution. The pH is the -log of the hydrogen ion concentration.

pipetter: a device used to accurately dispense a volume of liquid.

polar body : in animals, each meiotic division of the oocyte leads to the formation of one large cell (the egg) and a small polar body as the other cell.

polyacrylamide: a polymer formed by crosslinking monomers of acrylamide

polyglycolic acid : a biodegradable polymer

polymer: a molecule created by linking together a large number of a smaller molecule. The small molecule that is linked together is called a monomer.

polymerize, polymerization: the process of forming large molecules by covalently bonding a long chain of a smaller molecule (called a monomer) together.

power supply: a source of electric current used. A power supply is used in the SDS PAGE experiment, as well as in many other types of laboratory experiments. Some power supplies are adjustable, and have different modes of operation such as constant current and constant voltage modes.

primary antibody: NEED DEFINITION

primary cell culture: the cells produced from the initial harvesting of normal tissue.

primary structure: In terms of a protein molecule, the primary structure is the sequence of amino acid molecules in the protein.

primary_cell_culture: the cells produced from the initial harvesting of normal tissue.

probe: In the context of the immunoblotting experiments, the probe is a molecule that specifically binds to the protein that the investigator is trying to detect. In the Western Blotting experiment, the probe is an antibody raised against the protein of interest.

protein: a class of biological molecules that are formed by connecting a long chain of amino acid molecules Together.

reagent: a generic term referring to the chemical substances and solutions used during analysis, synthesis, and other processes where chemicals are consumed.

reducing agent: a substance that is capable of reducing another substance, often by donating electrons .

running buffer: a buffer used in the SDS PAGE experiment which contains SDS and buffering agents.

secondary structure: Localized three dimensional structure of the protein molecule caused by (generally) short range interaction between amino acids in the protein; examples of secondary structure include beta pleated sheets and alpha helix.

secondary antibody: NEED DEFINITION

SDS PAGE: Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis: A technique that is used to separate proteins in a mixture for the purpose of identifying them. SDS PAGE is a part of the Western Blotting technique.

seeding: initiation of a cell culture by adding primary cells to fresh media.

senescence: aging.

sodium dodecyl sulfate (SDS): a compound with detergent properties. In the SDS PAGE technique, SDS associates with the protein and denatures it, and gives it an overall negative charge.

specificity: NEED DEFINITION

subculture: a.k.a. "splitting" or "passage".The transfer of cells from one culture vessel to another. This usually involving the subdivision of a proliferating cell culture that has reached confluence.

supernatant: material floating on the surface of a liquid mixture (often the liquid component that has the lowest density).

suspension: particles floating in a liquid medium, or the mix of particles and liquid itself.

TEMED: (Acronym for Tetramethylenediamine) In the SDS PAGE reaction, this chemical acts as a catalyst in the polymerization of acrylamide.

tissue culture: a preparation made for the growth, storage, maintenance or transport of cells.

totipotent cell: an undifferentiated cell capable of developing into any type of body cell.

transfer buffer: NEED DEFINITION

Trypsin: a proteolytic enzyme most often used to dissociate cells from their culture vessels during subculture.

Trypan blue: the most commonly used stain to distinguish dead cells from live cells.

tunica intima: the inner layer of arteries and veins. In arteries this layer is composed of an elastic membrane lining and smooth endothelium that is covered by elastic tissues.

tunica media: the middle layer of the walls of arteries and veins. It is composed of smooth muscle and elastic fibers. This layer is thicker in arteries than in veins.

viability: life and health, ability to grow and reproduce; a measure of the proportion of live cells in a population

Western Blotting: a techhnique that uses antibodies to detect if a specific protein molecule is present in a mixture of protein molecules.