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Chemistry LibreTexts


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    Example and Directions
    Words that use this definition, Excluded words can be specified with an "!" The definition is case sensitive (Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages] (Optional) Caption for Image (Optional) External or Internal Link (Optional) Source for Definition Source License URL to Author
    (Eg. "Genetic, Hereditary, !Jeans ...") (Eg. "Relating to genes or heredity") The infamous double helix Delmar Larsen CC BY-SA
    Glossary Entries



    Image Caption Link Source Source License Source URL
    Death, Deaths, Multiple Deaths, Dying, !Deathstar

    An almost living being, especially an animal.


    libretexts_section_complete_photon_124.png This is a death star Delmar Larsen CC BY-SA
    Genetics The scientific study of genes and heredity, of how particular qualities or traits are transmitted from parents to offspring.       Delmar Larsen CC BY-SA
    Combinatorial Genetics A research process in which scientists remove the genetic instructions for entire metabolic pathways from certain microorganisms, alter the instructions, and then put them back.       Delmar Larsen CC BY-SA
    ADME Abbreviation for the four steps in a medicine's journey through the body: absorption, distribution, metabolism, and excretion.       Delmar Larsen CC BY-SA
    Agonist A molecule that triggers a cellular response by interacting with a receptor.       Delmar Larsen CC BY-SA
    Analgesic A medicine's ability to relieve pain, or a drug that alleviates pain; the term comes form the Greek word algos, which means pain.       Delmar Larsen CC BY-SA
    Antagonist A molecule that prevents the action of other molecules, often by competing for a cellular receptor; opposite of agonist.       Delmar Larsen CC BY-SA
    Antibiotic A substance that can kill or inhibit the growth of certain microorganisms.     Delmar Larsen CC BY-SA  
    Antibody A protein of the immune system, produced in response to an antigen (a foreign, often disease-causing, substance).       Delmar Larsen    
    Anti-inflammatory A drug's ability to reduce inflammation, which can cause soreness and swelling.       Delmar Larsen    
    Antipyretic Fever-reducing; the term comes from the Greek word pyresis, which means fire.            
    Arachidonic acid A molecule that synthesizes regulatory molecules such a prostaglandins; is found in fatty animal tissue and food such as egg yolk and live.            
    Bacterium, Bacteria One-celled organism without a nucleus that reproduces by cell division; can infect humans, plants, or animals.          
    Cholesterol A lipid unique to animal cells that is used in the construction of cell membranes and as a building block for some hormones.            
    Chromosome A structure in the cell nucleus that contains hereditary material (genes); humans have 23 pairs of chromosomes in each body cell, one of each pair from the mother and the other from the father.            
    Clinical trial A scientific study to determine the effects of potential medicines in people; usually conducted in three phases (I, II, III,), to determine whether the drug is safe, effective, and better than current therapies, respectively. Hausziege 04.jpg          
    Cyclooxygenase An enzyme, also known as COX, that makes prostaglandins from a molecule called arachidonic acid; the molecular target to nonsteroidal anti-inflammatory drugs.            
    DNA (deoxyribonucleic acid), DNA, deoxyribonucleic acid A double-stranded, helical molecule that encodes genetic information.            
    Dose The amount of medicine to be taken at one time.            
    Immunotherapy A medical treatment to stimulate a patient's immune system to attack and destroy disease-causing cells.            
    Inflammation The body's characteristic reaction to infection or injury, resulting in redness, swelling, heat, and pain.            
    Bioavailability The ability of a drug or other chemical to be taken up by the body and made available in the tissue where it is needed.            
    Bioinformatics A field of research that relies on computers to store and analyze large amounts of biological data.            
    Biotechnology The industrial use of living organisms or biological methods derived through basic research.            
    Biotransformation The conversion fo a substance from one form to another by the actions of organisms or enzymes.            
    Blood-brain barrier A blockade consisting of cells and small blood vessels that limits the movement of substances from the bloodstream into the brain.            
    Carcinogen Any substance that, when exposed to living tissue, may cause cancer.            
    Cell The basic subunit of any living organism; the simplest unit that can exist as an independent living system.            
    Central nervous system The brain and spinal cord.            
    Chemical bond Physical force holding atoms together to form a molecule.            
    Chemical genetics A research approach resembling genetics in which scientists custom-produce synthetic, protein-binding small molecules to explore biology.            
    Dose-response curve A graph drawn to show the relationship between the dose of a drug or other chemical and the effect it produces.            
    Enzyme A molecule (usually a protein) that speeds up, or catalyzes, a chemical reaction without being permanently altered or consumed.            
    Essential fatty acid A long, fat-containing molecule involved in human body processes that is synthesized by plants but not by the human body and is, therefore, a dietary requirement.            
    First-pass effect The breakdown of orally administered drugs in the liver and intestines.            
    G protein One of a group of switch proteins involved in a signaling system that passes incoming messages across cell membranes and within cells.            
    Gene A unit of heredity; a segment of a DNA molecule containing the code for making a protein or, sometimes, an RNA molecule.            
    Genomics The study of all of an organism's genetic material.            
    Hormone A messenger molecule that helps coordinate the actions of various tissues; made in one part of the body and transported, via the bloodstream, to tissues and organs elsewhere in the body.            
    Model organism A bacterium, animal, or plant used by scientists to study basic research questions; common model organisms include yeast, flies, worms, frogs, and fish.            
    Monoclonal antibody An antibody that recognizes only one type of antigen; sometimes used as immunotherapy to treat diseases such as cancer.            
    NSAID (nonsteroidal anti-inflammatory drug), NSAID, nonsteroidal anti-inflammatory drug Any of a class of drugs that reduces pain, fever, or inflammation by interfering with the synthesis of prostaglandins.            
    Informed consent The agreement of a person (or his or her legally authorized representative) to serve as a research subject, with full knowledge of all anticipated risks and benefits of the experiment.            
    Kinase An enzyme that adds phosphate groups to proteins.            
    Neurotransmitter A chemical messenger that allows neurons (nerve cells) to communicate with each other and with other cells.            
    Lipid A fatty, waxy, or oily molecule that will not dissolve in water; it contains hydrogen, carbon, and oxygen.            
    Nucleus The membrane-bound structure within a cell that contains most of the cell's genetic material.            
    Liposome Oily, microscopic capsules designed to package and deliver biological cargo, such as drugs, to cells in the body.            
    Organelle A specialized, membrane-bound structure that has a defined cellular function; for example, the nucleus.            
    Membrane A thin covering surrounding a cell and separating it from the environment; consists of a double layer of molecules called phospholipids and has proteins embedded in it.            
    Peptide A small protein fragment.            
    Pharmacodynamics The study of how drugs act at target sites of action in the body.            
    Metabolism All enzyme-catalyzed reactions in a living organism that builds and breaks down organic molecules, producing or consuming energy in the process.            
    Pharmacogenetics The study of how people's genes affect their response to medicines.            
    Metabolite A chemical intermediate in metabolic reactions; a product of metabolism.            
    Pharmacokinetics The study of how the body absorbs, distributes, breaks down, and eliminates drugs.            
    Pharmacologist A scientist focusing on pharmacology.            
    Recombinant DNA technology Modern techniques in molecular biology to manipulate an organism's genes by introducing, eliminating, or changing genes.            
    Pharmacology The study of how drugs interact with living systems.            
    RNA (ribonucleic acid), RNA, Ribonucleic Acid A molecule that serves as an intermediate step in the synthesis of proteins from instructions coded in DNA; some RNA molecules also perform regulatory functions in cells and viruses.            
    Pharmacy An area in the health sciences that deals with the preparation, dispensing, and appropriate use of medicines.            
    Sepsis A clinical condition in which infectious agents (bacteria, fungi) or products of infection (bacterial toxins) enter the blood and profoundly affect body systems.            
    Physiology The study of how living organisms function.            
    Side effect The effect of a drug, other than the desired effect, sometimes in an organ other than the target organ.            
    Prostaglandins Any of a class of hormone-like, fat-soluble, regulatory molecules made from fatty acids such as arachidonic acid; prostaglandins participate in diverse body functions, and their production is blocked by NSAIDs.            
    Signal transduction The process by which a hormone or growth factor outside the cell transmits a message into the cell.            
    Protein A large molecule composed of one or more chains of amino acids (the building blocks of proteins) in a specific order and a folded shape determined by the sequence of nucleotides in the gene encoding the protein; essential for all life processes.            
    Site of action The place in the body where a drug exerts its effects.            
    Proteomics The systematic, large-scale study of all proteins in an organism.            
    Steroid A type of molecule that has a multiple ring structure, with the rings sharing molecules of carbon.            
    Receptor A specialized molecule that receives information from the environment and conveys it to other parts of the cell; the information is transmitted by a specific chemical that must fit the receptor, like a key in a lock.            
    Structural biology A field of study dedicated to determining the three-dimensional structures of biological molecules to better understand the function of these molecules.            
    Therapeutic drug A drug used to treat a disease or condition; contrast with drug of abuse.            
    Toxicology The study of how poisonous substances interact with living organisms.            
    Virus An infectious agent composed of a protein coat around a DNA or RNA core; to reproduce, viruses depend on living cells.            
    X-ray crystallography A technique used to determine the detailed, three-dimensional structure of molecules based on the scattering of X rays through a crystal of the molecule.            
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