Allele: different forms of the same gene that code for different traits (ex. an allele could code for blue eyes, and a different allele of the same gene could code for brown eyes).

Alpha helix: a spiral structure that forms in proteins.

Alzheimer's disease: a disease in which the brain slowly degenerates due to the build up of protein.

Amino acid: a molecule that is the building block of proteins.

Amino acid substitution: the mutation of a gene to code for a different amino acid than it originally coded for, resulting in a protein that may have a different function than the original.

Amyloid plaques: protein build up in the brain that results in degeneration.

Antibodies:molecules of the immune system used to fight infection, but can also be use to target a specific protein for identification.

Astrogliosis: an loss of neurons that results in an increase in the number of glial cells, which are supporting cells of the nervous system

Beta sheet: a pleated structure that forms in proteins

Bioassay: using a model organism, such as a mouse, to determine the effect of a substance on that organism (in the case of TSEs, putting potentially infected tissue into a mouse to see if it develops into a disease, and determining whether the initial tissue was infected).

Bisacridine: a drug similar to quinacrinine, but more potent, that has shown some success in slowing down the progress of TSEs

Blood-brain barrier: the inability of substances in blood to reach the brain, due to a filter that protects dangerous substances.

Bovine spongiform encephalopathy (BSE): the form of TSE found in cows.

Brain imaging: the use of machines to look at brain tissue and search for disease

Brain stem: located at the back and bottom of the brain where it becomes the spinal cord; involved in "lower" functions, such as heart rate and breathing.

Cell cultures: cells grown in a lab used for tests.

Central nervous system: brain and spinal cord.

Cerebellum: located toward the back of the brain; plays are role in regulating smooth and coordinated movement.

Cerebral cortex: the surface of the brain; involved in higher cognitive functions.

Cerebrospinal fluid: the fluid that circulates in and around the brain.

Chlorpromazine: an antipsychotic drug that has been shown to slow the progression of TSEs.

Conformation: the shape taken by a protein.

Conformation-dependent immunoassay (CDI) : a test for prion disease that used a chemical to separate infectious from non-infectious prions.

Corneal transplant: a transplant of the outer layer of the eye.

Creutzfeldt-Jakob disease (CJD) : a form of TSE found in humans; it can be in a few different forms, including variant CJD, familial CJD and

Curcumin: a drug shown to help with TSEs.

Cytosol: the liquid present in a cell

Diluted brain homogenates:

Downer cows: cows that cannot stand on their own because of an illness or injury.

Dura mater: From the German for "hard mother" or "hard matter," the toughest outer layer of the meninges, three protective layers around the brain.

Endocannibalism: eating deceased members of the tribe that one belongs to; a former practice of the Fore tribe in Papua New Guinea

Endogenous proteins: a protein that is naturally made within the body.

Exogenous prion protein: a misfolded, infectious, external protein that has been introduced into the body.

Fibrous plaque: a protein buildup that is fibrous structure; contributes to neuron death.

Gait: the way an animal walks.

Gel: a technique used in science that uses a gelatinous substance to separate out molecules of different sizes and identify them.

Gene therapy: a way to treat diseases by changing the genetic material to code for a different protein; a potential treatment for prion diseases by changing the genetic code to code for a slightly changed prion protein that would be resistant to conformational change by infectious prions.

Gestmann-Scheinker syndrome (GSS): a hereditary form of human TSEs characterized by problems with eye, mouth and tongue movement, poor reflexes, abnormal walking, and memory loss.

Hematech: a genetic engineering company that produced a prion-free cow.

Hippocampal long-term potentiation: the process by which memories are stored as long-term memories in the brain.

Hippocampus: a structure in the brain that is involved in the transfer of memories from short term to long term.

Homeostatic regulation: the way that the body maintains balance (ex: temperature regulation).

Huntington's disease: a disease of neural degeneration from plaques in the brain.

Iatrogenic: resulting from medical treatment.

Immunoassay: a method of testing tissue for TSEs by eliminating all normal prion proteins and then detecting infectious prions by using antibodies with visual markers attached.

Immunohistochemistry: a method of testing for TSEs by injecting antibodies that will recognize the infectious form of prions into tissue and then examining a slide of that tissue for their presence.

Inoculation: the injecting of a substance into an organism to prevent later immunity to the disease.

Insidious: in reference to TSEs: developing gradually, and is therefore well-established before it becomes apparent

Insomnia: inability to sleep

Intravenous immunolglobin: a blood product used to treat immune disorders and autoimmune diseases.

Isoform: a protein with the same amino acid sequence, but a different shape.

Knock out: the genetic disruption of a gene so that the protein it encodes is not expressed and this absence can be observed to give insight as to the function of the protein.

Kuru: a form of human TSE caused by endocannibalism in the Fore tribe of Papua New Guinea.

Locomotor: relating to movement

Lymphatic system (lymph nodes) : a bodily system that carries fluid; involved in immune response

Lysosome: a cellular component that works to break down and recycle waste in the cell

Medulla: located toward the back of the brain in the brain stem, important in basic functions such as breathing and heart rate.

Memantine: a drug that showed some success in treating TSEs in mice

Molecular probes: molecules, often complementary DNA or RNA sequences used to study the function of certain genes in a cell.

Motor: movement

Myoclonus: brief, involuntary shudder or twitching.

Neuron: the basic unit of the nervous system; a cell that is important in performing brain and spinal cord functions.

Neurodegeneration: death of neurons; because the damage is not localized, individuals with TSEs display symptoms of widespread neurological damage: memory loss, motor deficiencies, behavioral changes.

Neurotoxicity: death of neurons.

Nucleases: an enzyme that destroys nucleic acids.

Nucleic acid: DNA or RNA: the genetic material of life.

Nucleotide sequence: the list of base-pairs that represent a gene.

Oligomer: a group of proteins that come together to form a functional unit.

Parkinson's disease: a disease of neurodegeneration that is partially due to the build up protein causing neuron death.

Peptide: a string of amino acids.

Peptide bond: the bond that occurs between two amino acids.

Peripheral nervous system: all neurons outside of the brain and spinal cord.

Plaque: a protein build up.

Prion diseases: neurodegenerative disease caused by the spread of misfolded prion proteins through out the brain; same as TSEs

Prion: a protein that, when misfolded, will induce normal proteins in the brain to misfold and contributes to neurodegeneration, causing TSEs.

Prion theory (prion hypothesis) : the idea that prions, without any nucleic acid, can be responsible for TSEs.

PrPC: the normal cellular form of the prion protein.

PrPSc: the infectious form of the prion protein.

Protease: an enzyme that breaks down protein

Protein: a chain of amino acids that folds into a specific shape

Protein misfolding cyclic amplifications (PMCA) : a method of increasing the number of infectious prion proteins (to make them easier to detect) by combining normal prions with infectious prions and mixing them to allow the infectious proteins to induce the normal proteins to misfold.

Psychosomatic: bodily symptoms caused by mental disturbance.

Quinacrine: an anti-malarial drug shown to have some effect in slowing the progression of TSEs in humans.

Scrapie: a form of TSEs present in sheep.

Sonication: the use of sound waves to break up protein clusters.

Species barrier: the inability of diseases to be transmitted between different species.

Squalestatin: a chemical substance that seems to cure neurons infected with prions and protect them against neuron death.

Surrogate marker: a molecule that is a indication of the presence of a disease, and can be easily used to identify the presence of that disease rather than the direct disease agent.

Synaptic function: the ability of neurons to send signals to each other.

Thalamus: a neural structure located above of the brainstem which plays a large role in sleep and wake-states.

Transmissible spongiform encephalopathies (TSEs) : diseases caused by infectious prion proteins; characterized by "spongy brain appearance" same as prion diseases.

Vacuole: a membrane-bound cellular component that is filled with liquid and enzymes.

Viscera: internal organs.