GLOSSARY
Welcome to viruses and how to beat them's interactive glossary.
For quicker access to a term you are looking for, click on the relevant letter. For some terms, we've added external resources.
Enjoy!
| A | |
|---|---|
| Acquired (or adaptive) immunity | The arm of the immune system mediated by B- and T-cell lymphocytes. Acquired immunity requires a learning period (about a week or so) before the protective response kicks in. The acquired (or adaptive) immune system is potent and highly specific for a given pathogen. The effect of B-cells is the production of pathogen specific antibodies. T-cells are able to detect infected cells and eliminate them. |
| Acute disease | An acute disease or infection is usually characterized by the fast onset of disease, sometimes severe symptoms and typical of the initial presentation of the disease. |
| Adjuvant | A molecule often used in vaccines to enhance the immunological response. The most common adjuvants for human use are aluminum salts. Typically the amount of aluminum is around 250 micrograms per vaccine. |
| Aerosol | Liquid droplets suspended in air. |
| Agar | A jelly-like material obtained from algae and originally used in Far East cooking. Agar revolutionized microbiology by providing a stable solid surface on which bacterial colonies can be cultured. |
| AIDS (Acquired Immuno- Deficiency Syndrome) | The immunodeficiency caused by HIV. |
| Allergens | The antigen that causes an allergic response. |
| amino-acid | The monomer of proteins. Each amino acid contains a central carbon – called carbon alpha. Carbon alpha is linked to an amine group (NH2) and an acid carboxyl group (COOH), hence these monomers are called amino-acids. Carbon alpha also binds one of 20 different R groups (residues). Thus there are 20 different amino acids that can be hydrophobic, polar or even electrostatically charged. |
| Amphipathic | Molecules that are both hydrophilic and hydrophobic. Soaps are amphipathic. |
| Antibody | Proteins produced by B-cells that specifically bind antigens. Antibodies are made of two heavy chain bound to two light chains. |
| Antigen | Any substance, recognized by the immune system. Typically proteins are strong antigens. |
| Antiseptics | Substances that kill bacteria often tolerated by otherwise healthy cells. Antiseptics are applied to wounded living tissue to reduce the chances of infection. |
| Atom | The atom is the defining structural unit of matter. Atoms contain sub-atomic particles: positively-charged protons and electrically neutral neutrons in the atomic nucleus. Negatively-charged electrons orbit the atomic nucleus. |
| Atomic number | The number of protons in the nucleus of an atom of a given element. |
| Atomic weight | The mass of an atom of a chemical element, The atomic weight approximately equals the number of protons and neutrons in the nucleus of that element. |
| Attenuated virus | Weakened virus – a virus that has been mutated to infect you but not cause disease or very mild disease. |
| B | |
| Bacteriophage | Is a virus that infects bacteria.
https://www.youtube.com/watch?v=i9L-RoQ1frc |
| BCR (B-cell Receptor) | The B-cell receptor is a transmembrane receptor found on the outer surface of B cells. The BCR is in essence a membrane bound antibody comprised of two heavy chains that extend and anchor the BCR to the membrane and two light chains that bind to the two heavy chains. |
| Binding site (antigen) | A region on the antibody that binds antigens. Typically, an antibody monomer has two identical binding sites. IgM molecules are made of 5 monomers (a pentameric structure) and thus contain 10 binding sites, IgG has two binding sites. |
| Bone Marrow | Bone marrow is a spongy tissue present in some of the bones of the body. This tissue is responsible for the production of red and white blood cells |
| C | |
| Carbohydrate (Saccharide) | A sugar molecule – sugars are "hydrated carbon" whose general formula is (CH2O)n. Glucose is a sugar monomer of the formula – C6H12O6 (where n=6). Starch, glycogen and cellulose are polysaccharides - they are polymers of glucose. |
| Carboxyl (COOH group) | An organic acid (COOH) |
| Cell | The basic structural, functional, and biological unit of all known living organisms. |
| Cell culture | a method of growing cells outside of their organism of origin.
https://www.youtube.com/watch?v=RpDke-Sadzo |
| Cell doctrine | The theory that cells are the fundamental structural and functional units of all living organisms. (proposed by Matthias Schleiden and Theodor Schwann, 1838): The Cell Doctrine states that: 1. All living organisms are made of CELLS 2. Cells are ALIVE! |
| Cell Line | An established pure cell culture, able to divide indefinitely. |
| Cell membrane | A lipid bilayer; a biological membrane typically made of phospholipids, which separates the interior of cells from the outside environment. The bilayer is arranged such that the polar heads face the water outside the cell and the water containing cytoplasm inside, while the fatty acid hydrocarbon tails from each leaflet of the bilayer face and intermingle with each other. This same arrangement is used in the formation of all the membranes within the cell that surround organelles. |
| Cell nucleus | The central organelle of a Eukaryotic cell that contains the cell's hereditary information - DNA. |
| Centigrade (oC) | A measurement unit of temperature which is derived from the Latin - centi (hundred) gradus (steps or degrees). Water freezes at 0oC and boils at 100oC. |
| Chargaff's rules | Erwin Chargaff was a biochemist that studied the nucleotide composition of DNA and formulated a set of rules – coined Chargaff’s Rules: 1. The DNA composition for a given organism is defined, constant and reproducible. 2. This DNA composition for different animal species varies. 3.The DNA compositions for a given specie does not change over time, with age, or from organ to organ. The concentration of G equals that of C and A equals T, these pair ratios, G to C and A to T always equal 1. |
| Chemical bond | Linking atoms together to form a molecule through sharing electrons. |
| Chemical element | A pure chemical substance composed of only one type of atom. |
| Chemokines | A family of cytokines that can induce directional cell movement. |
| chromosome | An enzyme which synthesizes polymers. DNA polymerase produces new strands of DNA against DNA templates. RNA polymerase produces RNA against a DNA template. Most RNA viruses have a RNA polymerase able to produce RNA against RNA templates. |
| Clonal expansion | A process in which thousands of daughter cells are generated from a single cell, in response to antigen binding. |
| CNS | Central nervous system. |
| codon | A triplet of nucleotides that codes for a specific amino acid or STOP signal. There are a total of 64 possible codons (43 combinations). |
| Collagen | A structural protein commonly found in the extracellular space of various connective tissues. |
| Communicable disease | Infectious diseases spread by pathogens. |
| condensation | Formation of a chemical bond between two molecules and the consequent release of a water molecule. |
| Conjugate vaccine | A vaccine containing a poor antigen linked to a strong antigen to boost the immunological response. Although sugar molecules can stimulate a B-cell response, this is often weak. In order to enhance the response, sugars of the bacterial coat can be chemically linked to proteins. In this manner a stronger immune response can be launched in response to vaccination. |
| Cowpox | An infectious disease caused by the cowpox virus and is related to smallpox. |
| Cross Reactivity (antibody) | The antibody's ability to recognize and bind an antigen slightly different from the original antigen that stimulated the B-cell in the first place. |
| Cytokines | A family of small proteins that regulate the immune response. |
| Cytopathic Effect – CPE | Destructive structural effects on cells that are caused as a result of viral infections. |
| Cytoplasm | The aqueous fluid of our cells. Cytoplasm contains proteins and other molecules as well as functional particles like ribosomes and proteasomes and bathes all the organelles, such as the ER and nucleus. |
| D | |
| Dendritic cell | A type of cell of the immune system that "captures" pathogens and transports them to lymph nodes to allow T and B cells to study them. |
| deoxyribose | The five carbon sugar of DNA. Deoxyribose is missing a hydroxyl group at carbon 2. |
| Dermis | The inner layer of the skin, rich in blood vessels, sweat glands and hair follicles as well as lymphatic vessels. |
| Differentiation | A process in which a cell, usually a stem cell, can develop from a non-committed, general cell into a highly specialized cell type. After differentiation, the fully specialized cell usually can no longer divide or revert to its original non-committed state. |
| DNA(Deoxyribonucleic Acid) | Deoxyribonucleic acid (DNA) is the polymer our genes are made of. DNA is made of two polynucleotide chains containing deoxyribose. The two strands form a double helix in which the chains run antiparallel to one another. The sugar-phosphate backbones face outward while the nitrogen bases face inward and base pair G to C and A to T. |
| E | |
| Effector signal (antibody) | The Carboxy end of an antibody’s heavy chains forming a “stalk” that can interact with different immune cells by an Fc Receptor. |
| Elastin | Elastin is an extracellular protein that provides resilience and elasticity to tissues and organs. |
| Electron | A negatively charged particle found in atoms, that orbits the nucleus. |
| Endoplasmic Reticulum (ER) | An extensive network of intracellular membranes that is often associated with ribosomes active in producing proteins that need to be exported and secreted out of the cells. Antibodies and cytokines are made on ribosomes bound to the ER. The enzymes of lysosomes, the organelles that breakdown bacteria eaten by macrophages are also made on ribosomes bound to the ER. So are MHC and Fc receptors. |
| Enveloped and Non-Enveloped Virus | Some viruses have a lipid membrane envelope that covers and coats the capsid. This membrane is derived from the host cell and coats the virus as it emerges and buds from the infected cell. Some viruses disrupt the cell and emerge without an envelope and are referred to as non-enveloped or naked viruses. Flu is enveloped while polio is a naked virus. |
| Enzyme | A protein that carries out chemical reactions in our body. |
| Epidermis | The outer layer of the skin, comprised of multiple skin layers keratinocytes and rich in keratin.
The outermost layer is made of dead keratinocytes and is continually being sloughed off and replaced by underlying keratinocytes. |
| Epithelium (Epithelial cells) | The cellular lining of the mucosa. |
| epitope | The specific surface of an antigen that is directly recognized by an antibody for example. |
| Eukaryote | An organism whose cells have a membrane bound nucleus. All multicellular organisms are Eukaryotes, e.g., plants and animals. |
| F | |
| Fatty acid | An organic acid group (COOH) connected to a chain of hydrocarbons (carbons bound to hydrogens). Typically the hydrocarbon tail can be 12-20 carbons long. A fatty acid is said to be "saturated" if all the carbons in the hydrocarbon tail are bound to 2 or 3 hydrogens. When two or more carbon atoms of the hydrocarbon tails are linked between themselves via double chemical bonds, these carbons are said to be "unsaturated". |
| Fibroblasts | A type of cell commonly found in connective tissues. |
| Flagellum (plural Flagella) | A motile lash-like appendage that protrudes from the cell body of certain bacteria and enable them to swim about. A major component of flagella is the bacterial protein flagellin which is a PAMP and thus can induce an innate response when recognized by specific PRRs. |
| FMT (Fecal Microbiota Transplant) | Fecal Microbiota Transplant is a relatively new therapeutic treatment of gut disease caused by pathogenic bacteria that have displaced beneficial bacteria of our microbiome. |
| G | |
| Genetic Code | The set of 64 codons corresponding to the 20 natural amino acids + three Stop codons. The code is redundant – that is all amino acids have multiple codons, except for Methionine and Tryptophan which have only one codon (AUG and UGG, respectively). Codons are read from 5' to 3'. |
| Genetic drift | Genetic variations caused by naturally occurring mutations.
https://www.youtube.com/watch?v=ug-M1nIhfIA |
| Genetic shift | Genetic variations caused by exchange of a gene segment (for example in flu).
https://www.youtube.com/watch?v=nLGyUL3psM4 |
| Golgi apparatus | The loading dock and distributer of proteins made in the ER. This membrane structure sorts the proteins made in the ER and sends them to other organelles such as the
Lysosome , or to export out of the cell, or to cell membranes. TLRs and the MHC proteins are proteins of the cell's outer membrane that were handled first by the Golgi apparatus. |
| H | |
| Hair Follicles | A skin organ that produces hairs. |
| Heavy chain | The large (or heavy) polypeptide subunit of an antibody. Heavy chains typically are made of 450-550 amino acids. The specific heavy chain defines the type of antibody molecule, i.e., IgM, IgG, IgA and IgE. |
| HeLa cells | A cell line used extensively in biological research. This cell line was derived from the cervical cancer of the patient Henrietta Lacks [1951].
https://www.youtube.com/watch?v=sXY6-wLesYY https://www.youtube.com/watch?v=22lGbAVWhro |
| Hematopoietic Stem cells | Hematopoietic stem cells can differentiate into RBS and WBCs, phagocytes and lymphocytes. |
| Hemorrhagic fever/disease | An illness that causes bleeding and elevated temperature.
http://www.who.int/topics/haemorrhagic_fevers_viral/en/ https://en.wikipedia.org/wiki/Viral_hemorrhagic_fever |
| HIV (Human Immunodeficiency Virus) | A retrovirus that causes AIDS. |
| Hydrogen bond | A bond formed through electrostatic attraction between a polar group of one molecule and a polar group of opposite charge in the same or other molecule. Two water molecules can hydrogen bond; the oxygen atom of one molecule is attracted to the hydrogen of the other. DNA base pairs bond G to C and A to T via hydrogen bonds. |
| Hydrolysis | A reaction in which a chemical bond is broken within a molecule and a water molecule is consumed. |
| Hydrophilic | "Attracted to water". Molecules that contain polar groups are hydrophilic and thus are able to interact with water via hydrogen bonds. |
| Hydrophobic | "Afraid of water". Non-polar molecules (molecules lacking polar groups) are unable to interact with water, repel water and are thus referred to as hydrophobic. Oils are hydrophobic. |
| Hydroxyl (OH group) | A chemical group – OH, that consists of one hydrogen atom bound to an oxygen atom. |
| I | |
| IgA | A type of antibody comprised of two antibodies monomers linked together and mainly found in the mucosa. |
| IgE | The least common type of antibody. Plays a role in fighting off parasites. IgE is bound by mast cells. Binding of its antigen triggers histamine release by the mast cell. IgEs are central to the allergic response. |
| IgG | The most common type of antibody found in the blood. |
| IgM | A type of antibody comprised of five antibody monomers linked together. IgM is the first antibody to be secreted by a B-cell in response to interacting with its corresponding antigen. |
| Immunodeficiency | A state in which the immune system is compromised and is unable to defend the body against pathogens and cancer. |
| Immunoglobulin | An alternative term for antibody. Immunoglobulins refer to soluble antibodies and not to the membrane bound BCR. |
| Index patient (patient zero) | The first patient affected by a condition or syndrome to be described in the medical literature or in an epidemiological investigation. |
| Infected host | An infected person, animal, plant, organism or cell that harbors a pathogen, such as a virus, parasite or disease causing bacterium. |
| Inflammation | An immune response often triggered by pathogens leading to: (i) redness, (ii) swelling, (iii) heat and (iv) pain. This response is often associated with the innate response to infections. Inflammation can also be mounted in situations not stimulated by infection. This is sometime deleterious and associated with auto-immune diseases such as arthritis. |
| Innate immunity | The pre-existing arm of the immune system which we are born with. Innate immunity is characterized by an immediate and non-specific response to pathogens. Unlike the adaptive immune system, the innate system does not require “training” and the need to “learn” the details of the specific pathogen. Furthermore, innate immunity does not provide long lasting immunity via immunological memory. |
| Interferon | A cytokine made and released by host cells in response to the presence of viruses. |
| Interstitial space | The spaces between the cells of our organs. |
| IPV (Inactivated Polio Vaccine) | A polio vaccine developed by Jonas Salk. The virus is inactivated with formaldehyde and administered via injection. |
| J | |
| K | |
| Keratin | A tough fibrous protein that protects epithelial cells from damage. |
| Keratinocytes | The predominant cell type of the epidermis that produces the keratin protein. |
| "Killed" virus | Chemically inactivated virus. |
| L | |
| Leptin | A hormone produced by fat cells that among other functions, is important for the development of T-cells. |
| Light chain | The small (or light) polypeptide subunit of an antibody (about 220 amino acids long). |
| Lipid | Hydrophobic organic molecules that often contain two fatty acids linked together. Three fatty acids linked together form the lipid - triglyceride. Cholesterol is also considered a lipid even though it does not contain fatty acids. |
| "Live" virus | Infectious virus. |
| LPS (lipopolysaccharide) | Large molecules consisting of lipid and a polysaccharide components found in the outer membrane of Gram-negative bacteria, and elicit strong immune responses in animals. |
| Lymph node | An ovoid organ of the lymphatic system located at points of convergence of where lymphatic vessels converge. Its primary function is to collect and filter bodily fluids that may contain antigens and pathogens so that the B and T cells present in the nodes can interact and study them. |
| Lymphatic system | The lymphatic system is a network of interconnected vessels, tissues and organs that acts as the body's drainage system. By having a large concentration of lymphocytes, the lymphatic system plays a pivotal role in defending the body against infections. |
| Lymphocytes | A subtype of WBCs that include T-cells and B-cells. These cells belong to the adaptive immune system and are characterized by a highly specific response towards a pathogen. |
| Lysosome | An intracellular organelle full of digestive enzymes produced in the ER and distributed by the Golgi apparatus. These lysosomal enzymes function to digest and breakdown worn-out organelles, food particles, and engulfed viruses or bacteria. |
| Lysozyme | An antimicrobial enzyme produced by animals that forms part of the innate immune system. Lysozyme is secreted in saliva and tears and was discovered by Alexander Fleming. This discovery led to the discovery of penicillin. |
| M | |
| Macromolecule | A large complex molecule, such as DNA, proteins, carbohydrates, and lipids. Macromolecules typically contain hundreds and thousands of atoms. |
| Macrophages | A type of phagocytic white blood cell found in many tissues such as skin and the mucosa. |
| Mast cell | A special type of immune cell that is rich in histamine containing granules. Mast cells have TLR and Fc receptors, especially Fc receptors that bind the effector signal of IgE molecules. Thus mast cells are decorated by many different types of IgEs. When these bind to their corresponding antigens, the mast cell releases histamine which leads to a violent immune response. |
| MHC | A family of cell surface complexes found on most of the cells of our body. The MHC binds peptides that are generated by the proteasome and displays these peptides on the surface of the cell. This system constantly presents samples of the proteins being produced in given cell and thus functions as the quality control system of the body. The peptides presented via MHC are screened by T-cells. When viral proteins are displayed by MHC, T-cells identify the MHC/viral-peptide complex by the T-cell receptor and knock out the infected cell. |
| Microbiome | The collection of billions and billions of bacteria that live in us, on us and with us. The vast majority of these bacteria are harmless and are actually beneficial. |
| Microcephaly | A serious birth defect in babies in which their brains develop poorly resulting in a smaller than normal sized head and usually cognitive deficits. |
| Mitochondria | A complex organelle that breaks down sugars and lipids from the foods we eat. This produces the energy that the cell uses to produce new proteins, replicate DNA, build muscles and bones and maintains our cells. |
| Molecule | Two or more atoms held together by chemical bonds. Chemical bonding consists of sharing electrons. |
| Monomer | The basic structural subunit of polymers. Monomers bind to each other to form polymers. |
| mRNA | Messenger RNA, the working copy of the DNA gene, translated on ribosomes to produce proteins. |
| Mucosa | A layer of cells that lines various cavities in the body and surrounds internal organs. |
| Mucus | A viscous protein secreted to protect the inner linings of our body. |
| Mutation | An error in DNA which can lead to a change in a protein composition, structure and function. Mutations that create “Stop codons” can entirely prevent the production of the mutated protein. |
| N | |
| Naïve | A person, organism or cell that has not been infected by a pathogen. The term naïve also refers to those who have not been exposed to pathogens or their antigens. |
| NCD - Non-communicable Disease | a chronic disease such as cancer, heart-disease and diabetes. These diseases are not contagious. |
| Neutron | A neutral (uncharged) particle located in the nucleus of atoms. |
| Neutrophils | The most abundant type of WBC. Neutrophils are effective phagocytes. |
| NK cell (Natural Killer cell) | A special type of lymphocyte that is able to detect infected cells and knock them out. |
| Non-Structural Proteins | All the proteins coded for by the viral genome that do not contribute to the structure of the virus. Viral polymerases are for example non-structural proteins. |
| Nucleotide | A molecule comprised of a nitrogen base, a 5-carbon sugar and a phosphate group. It is the monomeric unit of DNA and RNA, depending on the type of sugar. Deoxyribose is the sugar in DNA whereas ribose is the sugar in RNA. |
| O | |
| OPV (Oral Polio Vaccine) | A polio vaccine developed by Albert Sabin containing “live” attenuated virus and is administrated via oral drops. |
| Oral-Fecal transmission | Transmission of pathogens from fecal waste ingested orally by a host. Commonly, soiled hands can contaminate articles such as clothing and utensils with fecal-pathogens that can then subsequently be passed on to others.
https://en.wikipedia.org/wiki/Fecal%E2%80%93oral_route http://www.healthhype.com/stool-to-mouth-or-fecal-oral-route-of-transmission-of-infection.html |
| Organelles | Subcellular structures; such as the nucleus, endoplasmic reticulum and mitochondria, that are surrounded by one or two lipid bilayers. |
| Organic chemistry | The chemistry of the element: carbon. |
| P | |
| PAMPs (Pathogen Associated Molecular Patterns) | Molecules typical of pathogens that are recognized by cells of the innate immune system. |
| Pathogen | A disease-causing agent such as bacteria, parasites, fungi and viruses. Derived from the Greek - pathos (suffering) and genes (the producer of). |
| Penicillin | The first antibiotic and was discovered by Alexander Fleming. Today, numerous commercial antibiotics - similar in structure and function to penicillin, are produced and widely used in medicine and agricultural growth of livestock. |
| Peptide bond | The chemical bond that joins two amino acids. Peptide bonds are the product of a condensation reaction in which the amine of one monomer links with the carboxyl of the other along with releasing a molecule of water. |
| Periodic Table | A table of the chemical elements - arranged by consecutive atomic numbers. |
| Phagocytes | WBCs of the immune system that specialize in ingesting harmful pathogens, foreign objects and dead cells. Macrophages and neutrophils are the major phagocytes of the innate immune system. The term is derived from the Greek phagein which means "to eat" or "devour". |
| Phagosome | A membrane-bound vesicle in a phagocyte containing the engulfed pathogen/particle. |
| Phospholipid | A lipid in which the two fatty acids are also linked to a phosphate group. The phosphate group is often further bound to additional hydrophilic groups. Phospholipids are amphipathic; the hydrophobic fatty acid tails being linked to the polar phosphate containing group. |
| Pico | A unit prefix symbolizing a factor of 10-12 |
| Plasma | Plasma is the fluid of blood. It is a clear, yellowish liquid making up 55% of the blood's volume. Plasma contains nutrients, proteins and enzymes, hormones and antibodies. Specifically, plasma contains the enzymes responsible for blood clotting. When these proteins are removed, the plasma is then referred to as “serum”. |
| Polar | An uneven distribution of charge within a molecule. Water is polar; its oxygen is relatively more negative than its hydrogens, while the molecule as a whole remains neutral. |
| Poliomyelitis | Infantile paralysis caused by the polio virus. |
| Polymer | A large molecule composed of many repeated subunits - monomers. |
| Polymerase(DNA/RNA) | An enzyme which synthesizes polymers. DNA polymerase produces new strands of DNA against DNA templates. RNA polymerase produces RNA against a DNA template. Most RNA viruses have a RNA polymerase able to produce RNA against RNA templates. |
| Prokaryote | A single-cell organism that does not have a membrane bound nucleus. Bacteria are prokaryotes. |
| Proteasome | A large enzyme complex tasked with degrading and recycling cellular proteins into their amino-acid building blocks. Proteasomes can breakdown proteins into short peptides that are presented on the cell surface by the Quality Control complex – MHC. https://pdb101.rcsb.org/motm/166 https://www.youtube.com/watch?v=-GwI-UrhpEo |
| Protein | A polymer of amino-acids joined by peptide bonds. Proteins are the product of the translation of mRNA on ribosomes. |
| Proton | A positively charged particle located in the nucleus of atoms. |
| PRRs (Pattern Recognition Receptors) | Pattern recognition receptors are receptors that detect molecules typical for pathogens such as PAMPs. |
| Pus | A viscous, yellowish-white fluid formed in infected tissue, consisting of white blood cells, cellular debris, and dead bacteria. |
| Q | |
| R | |
| Red blood cells (RBCs) | Red blood cells (erythrocytes) are the most common type of blood cells found in our body. RBCs are full of hemoglobin a protein that contains iron. As a result RBC can transport oxygen from our lungs to every cell of the body. They also remove carbon dioxide. |
| Reverse transcriptase | A non-structural polymerase of retroviruses. This enzyme uses the viral RNA template to produce a double stranded DNA copy of the viral genome – the pro-virus. |
| Ribose | The five carbon sugar of RNA. Ribose has hydroxyl groups at carbons, 1, 2, 3, and 5. Carbon 1 binds the nitrogen base and carbon 5 the phosphate group of ribonucleotides. |
| Ribosome | A subcellular structure that translates messenger RNA (mRNA) into its corresponding Protein. Ribosomes are molecular "machines" that recognize the mRNA that needs to be translated, identifies the "reading frame" (the point to begin reading) of a given mRNA and is able to read the genetic code – the three letter codons, as well as actually link the amino acids via peptide bonds. |
| RNA (Ribonucleic Acid) | A single stranded polymer of nucleotides, in which the 5 carbon sugar is ribose. RNA molecules use the nitrogen base uracil (U) instead of thymine (T) found in DNA, which base pairs with Adenine. |
| S | |
| SCID (Severe Combined Immunodeficiency) | A genetic disorder in which the development of T and B cells is compromised resulting in a dysfunctional immune system. |
| Sebaceous Glands | Small structures of the skin that secrete oils. |
| Sialic-Acid | A monosaccharide comprised of a nine-carbon backbone and contains an acidic group (COOH). These sugars are commonly found on the surface of mammalian cells, thus, some viruses have evolved to use these sugars as their specific receptors. Flu virus uses sialic acid as its receptor. The manner in which sialic acid links to other sugars on the cell surface may affect the ability of the virus to recognize and infect a potential host cell. |
| Skin | The skin is one of the largest organs of our body. Consisting of several layers, the skin is our first line of defense against pathogens. |
| Spleen | The spleen is the largest organ of the lymphatic system. It functions to: 1. filter out dead or damaged red blood cells and store a reserve of blood in case of an injury. 2. it plays a vital role in interacting with B and T cells in the fight against pathogens present in blood. |
| Stem cells | Stem cells are able to differentiate into specialized cell types. |
| Stop Codon | A codon that signals the termination of mRNA translation. Stop codons appear at the end of the reading frame of a mRNA and thus indicate that the Protein being translated has reached completion. |
| Structural Proteins | Proteins that construct the virus, such as capsomers and spike proteins. |
| Subunit vaccine | A vaccine containing only select antigens of the pathogen. Typically the spike protein of a virus as is the case for Hepatitis B virus. |
| Susceptible | Cells that express the receptor for a given virus and consequently can be infected by that corresponding virus are referred to as susceptible. |
| Sweat Glands | Small structures of the skin that produce sweat. |
| Syncytium | Syncytium (plural: syncytia) is a multinucleated cell that results from the fusion of several cells.
http://viralzone.expasy.org/all_by_species/5957.html |
| T | |
| TCR (T-cell Receptor) | A receptor found on the T-cell membrane. The TCR recognized the MHC and is able to discriminate between self vs non-self peptides. When the MHC displays non-self peptides and is bound by the TCR, this triggers the TCR to kill the infected cell. |
| Thymus | The thymus is a primary lymphatic organ located just in front of the heart. Inside it, T cells undergo differentiation. |
| TLR (Toll Like Receptor) | Toll-like receptors are a class of receptors of the innate immune response. TLRs are found on macrophages, dendritic cells and other cell types. There are numerous TLRs and can be specific for bacterial PAMPs and viral PAMPs such as double stranded RNA. Binding of PAMPs to TLRs triggers the secretion of cytokines and other effector proteins such as interferon. |
| Toxoid | An inactivated toxin. The toxins produced by bacteria can be inactivated with formaldehyde to produce an inactivated protein thdat can still simulate the B-cells to produce neutralizing antibodies. |
| U | |
| Ubiquitin | a regulatory protein that tags and targets cellular proteins for degradation by the proteasome.
https://www.youtube.com/watch?v=u9EGAAys7ZU https://pdb101.rcsb.org/motm/60 |
| V | |
| Vaccine boost / boost dose | An extra administration of a vaccine in order to enhance the immunological response. The first vaccination stimulates a primary response. However subsequent exposure to the vaccine greatly improves the response and fortifies the memory as well. Thus most vaccination schedules start with the primary initial vaccination followed by a series (one or two booster shots). In some cases booster shots are recommended after many years to re-stimulate the immune system. |
| Valence | The ability of an atom to share electrons and form chemical bonds. Carbon has 4 valences, Oxygen 2 and Hydrogen 1. |
| Vector | The animal reservoir of the zoonotic transmitted pathogens.
https://www.youtube.com/watch?v=Ao0dqJvH4a0 https://en.wikipedia.org/wiki/Natural_reservoir https://www.cdc.gov/flu/about/viruses/transmission.htm |
| Viral Capsid (capsomere) | A protein shell comprised of subunits called capsomers and functions to encompass and protect the viral DNA or RNA. |
| Viral plaque | Areas in continuous cell cultures devoid of cell growth due to viral infection and spread. https://www.youtube.com/watch?v=er2dwOPwSRo http://www.virology.ws/2009/07/06/detecting-viruses-the-plaque-assay/ |
| viremia | The presence of viruses in blood.
http://diseasespictures.com/viremia/ https://en.wikipedia.org/wiki/Viremia |
| W | |
| White blood cells (WBCs) | White blood cells (leukocytes) are the cells of the immune systems found in our blood or within tissues. White blood cells can be divided into two categories: phagocytes and lymphocytes, both cell types function to protect us against pathogens. |
| X | |
| Y | |
| Z | |
| Zoonosis | Transmission of pathogens from animals to other animals or people. Transmission of pathogens from people to animals is also zoonotic.
Hence transfer of viruses from people to mosquitoes and then mosquitoes to other people is a common zoonotic cycle. https://www.youtube.com/watch?v=up7ye3yvzyY http://www.who.int/zoonoses/en/ |