text:
SPARQ-ed glossary
Acetyltransferase – an enzyme which attaches an acetyl group to a protein.
Actin – a protein which plays a major role in the cytoskeleton and cellular movement.
Acute – a state of a disease characterized by severe symptoms which manifest over a short period of time.
Adaptive Immunity – immunity generated against a specific target.
Adaptor Protein – a protein which transmits the signal from a receptor to a signal transduction cascade.
Adenylate Kinase – an enzyme which catalyses the phosphorylation of ADP to make ATP. As the enzyme is found only in the cytoplasm of the cell and is not secreted by healthy cells, measuring levels of adenylate kinase in tissue culture media is a useful assay for cell death.
Adipocyte – a cell which stores lipids in large vacuoles.
Adiponectin – a protein hormone produced by fat storing cells which is involved in the control of cellular metabolism. More information on Adiponectin can be found in the introduction to the project 1 manual.
Adult Stem Cells – stem cells derived from the tissues of an organism which has completed embryonicdevelopment.
Adipose Tissue – a specialized group of cells whose role is to store fats.
Affinity Purification – a method of purifying substances by specifically binding them to inert materials and washing away other products. Substances bound can then be recovered by washing out ("eluting") with a different solution.
Agar – a jelly-like substance derived from seaweed and used to make solid culture media.
Agarose – a substance derived from seaweed which forms a gel when dissolved in water. Agarose gels are used in DNA electrophoresis.
AKT (also Protein Kinase B) – an important signaling molecule involved in the response to insulin in the cell.
Alcian Blue – a dye which demonstrates the glycoproteins associated with cartilage.
Alginate – a polysaccharide derived from seaweed which forms a hydrogel when exposed to calcium ions
Alizarin Red S – a dye which demonstrates the presence of calcium salts.
Alkaline Phosphatase – an enzyme produced by osteoblasts in the early stages of their differentiation from mesenchymal stem cells.
Allele – a variation of a particular gene.
Aliquot – to deliver a measured sample of a liquid.
Allograft – a tissue transplant from a non-genetically identical donor.
Alpha Helix - an example of protein secondary structure where the peptide chain takes on a spiral conformation.
Amino Acid – a small organic molecule which has a component which acts as a base (an amine group –NH2) and one which acts as an acid (carboxyl group –COOH). Amino acids are the building blocks of proteins. Hanging off the central carbon atom is a side chain (often given the abbreviation R) which differentiates one amino acid from another. There are approximately 20 different amino acids which are used to make proteins. More information on amino acids and proteins can be found here.
Amphipathic – a compound which contains both hydrophilic and hydrophobic regions.
Ampicillin – an antibiotic compound used in selective media.
AMP Kinase – a protein complex involved in the maintenance of energy balance in the cell.
Analogue – a compound with a chemical structure similar to another compound.
Anaphase – the phase of mitosis characterised by the separation of the chromosomes into the daughter chromatids and their movement to opposite poles of the dividing cell.
Anauxetic Dysplasia – a genetic condition characterized by extreme short stature, abnormalities of the facial bones, long bones and digits and mild mental retardation. Anauxetic dysplasia is caused by mutations within the RMRP gene.
Androgen – hormones responsible for the development and maintenance of male characteristics.
Androgen Ablative Therapy – a type of therapy for prostate cancer which involves limiting the effect androgens like testosterone have on the growth and progression of cancer cells.
Aneuploidy – unequal or otherwise abnormal distribution of chromosomes following mitosis.
Angiogenesis – the growth of new blood vessels.
Anionic – having a negative charge.
Ankylosing Spondylitis (AS) – an autoimmune condition which causes inflammation of the joints in the spine and which may eventually lead to fusing of vertebrae.
Annealing – "joining together" – in PCR, annealing refers to the step in the cycle where primers attach to the template DNA strand.
Antibody – a specialised protein molecule produced as part of the immune response which binds specifically to other molecules.
Antagonist – an agent which causes a reduced response.
Antibiotic – a compound which interferes with the growth of micro-organisms, particularly bacteria.
Antigen – an agent to which an antibody binds.
Antigen Presenting Cell (APC) – a type of cell which processes proteins from both foreign agents and self and presents fragments of these proteins on their surfaces for recognition by elements of the immune system.
Apoptosis – a type of controlled cell death. Unlike necrosis, the breakdown of the cell occurs in an orderly fashion and cellular components are compartmentalised and removed before they can trigger inflammation or necrosis in neighbouring tissue.
Aqueous – a solution in which the solute is dissolved in water.
Arthritis – a condition characterized by inflammation of and damage to the tissues of the joints.
Aspirate – to remove the liquid from a sample using a vacuum line. Aspirated materials are usually disposed of.
Atherosclerosis – a medical condition characterized by the accumulation of fatty deposits in the blood vessels. Also known as "hardening of the arteries" because affected blood vessels may lose their elasticity.
ATM (ataxia telangectasia mutated) – a protein which activates Chk2 in response to double-stranded DNA damage.
ATP (adenosine triphosphate) – a molecule used as the energy currency in cellular metabolism, as a donor of phosphate groups in phosphorylation reactions and which forms one of the building blocks of DNA.
ATR (ataxia telangectasia and RAD3 related protein) – a protein which activates Chk1 in response to single-stranded DNA damage.
Attenuation – the gradual weakening of a signal.
ATTλ – a nucleotide sequence found in both viral and bacterial genomes which allows recombination between the two.
Aurora A – a kinase which associates with the centrosome and is involved in centrosome separation and formation of the spindle apparatus during mitosis.
Aurora B – a kinase which associates with the kinetochore microtubules and is involved in attached of chromosomes to the spindle apparatus and chromosomal segregation during mitosis.
Autoantibody – an antibody directed against the host's own antigens.
Autocrine – referring to a hormone system in which the hormone affects the cells which produced it.
Autophosphorylation – the process of an enzyme attaching a phosphate group to itself or to identical enzymes.
Autoimmune Disease – a condition which results from the body's immune system attacking its own tissues.
Avidin – a protein found in egg white which binds strongly to biotin.
Bacterium – a microorganism with a cell wall but which lacks membrane-bound organelles.
BALB/c – a commonly used strain of albino laboratory mice.
Band – region of a gel in which proteins or DNA fragments of a particular size are concentrated after electrophoresis.
BARD1 (BRCA1 Associated RING Domain protein 1) – a protein that binds to the RING domain of BRCA1. The resulting complex is involved in the ubiquitination of other proteins.
Basement Membrane – a non-cellular structure which lies beneath an epithelium.
Bases – the four organic molecules which are found in nucleotides. The bases found in DNA are adenine, thymine, guanine and cytosine. In RNA, thymine is replaced by uracil.
Basophil – a type of granulocyte involved in the release of histamine and other initiators of the inflammatory response.
B Cell – a type of lymphocyte produced in the bone marrow. Once activated by the presence of a disease agent, B cells either transform into plasma cells which produce antibodies directed against that agent, or become memory cells which provide long-lasting immunity.
Benign Tumour – a localised tumour which is not considered to be at risk of metastasis.
Beta (β) Cells – cells in the pancreas which produce insulin.
Beta Pleated Sheet - a form of protein secondary structure where the peptide takes on the shape of a folded sheet.
Binucleate - having two nuclei as a result of a failure of cytokinesis during mitosis.
Bioavailability – the degree to which a therapeutic agent can reach the site where it acts.
Biochemistry – the study of the chemistry of living things.
Bioluminescence – the emission of light by living organisms.
Biomarker – a protein whose presence or level of expression is an indicator of a cellular process.
Biomolecule – a complex organic compound which is made as the result of a biological process. Also called macromolecules, because most are quite large.
Biotin – a metabolite which binds strongly to avidin. Biotin is also known as vitamin B7.
Blastocyst – an early stage of embryonic development in which some tissue differentiation has occurred, typically 3-5 days post fertilisation in humans.
Blotting – a technique where bands containing specific proteins are demonstrated using labeled antibodies raised against those proteins.
Bone Marrow – a complex tissue found which cavities in certain bones which contains several stem cell lines (eg. haematopoietic stem cells, mesenchymal stem cells).
Bone Morphogenic Proteins (BMP) – a family of proteins which act as growth factors for osteoblasts and encourage the deposition of bone tissue.
Bowman's Capsule – a sac surrounding the glomerulus. Fluid within the Bowman's capsule eventually becomes urine.
BRCA1 (Breast Cancer Susceptibility Gene 1) – the gene that codes for the DNA repair protein BRCA1. Mutations in BRCA1 are associated with an increased risk of developing cancers, particularly breast cancer.
BRCA2 (Breast Cancer Susceptibility Gene 2) – the gene that codes for the DNA repair protein BRCA2. Mutations in BRCA2 are associated with an increased risk of developing cancers, particularly breast cancer.
BRCT Domains (BRCA C-Terminal Domains) – regions at the C-terminus of BRCA1 and BRCA2 involved in interactions with proteins phosphorylated by ATM and ATR in response to DNA damage. Mutations in the BRCA1 and BRCA2 genes in these areas are associated with a wide range of cancers.
Broth – a liquid form of culture medium.
BSA – bovine serum albumin – a protein solution derived from the blood of cows which is used to stabilize restriction digests.
Buffer – a solution of chemicals which resists the change of pH which would normally occur when an acid or base is added.
C33A - a cervical cancer cell line derived from a cancer not induced by HPV.
Caffeine – in cell biology, caffeine is used to inhibit the DNA repair pathways initiated by ATM and ATR.
Cancer – a family of conditions characterised by uncontrolled cell growth, infiltration into neighbouring tissues and occasionally spread to other tissues in the body.
Capillary – the finest of the blood vessels, with walls a single cell thick.
Capsid – the coat of protein which surrounds the genetic material of a virus.
Capsomere – one of the protein subunits which makes up the capsid of a virus.
Carbohydrate – a biomolecule group based around the sugars. Carbohydrates are broken down to provide energy for cellular processes, they may form structural components of the cell, and they are involved in cellular recognition.
Carcinogen – an agent capable of causing cancer.
Carcinogenesis – the development of cancer.
Castration – removal of the testes. As these organs are the primary producers of testosterone in males, castration is used as an androgen ablative therapy.
Catalytic Domain – the region of an enzyme which assists in chemical reactions.
Cationic – having a positive charge.
Caveolae – small, flask-like invaginations of the cell membrane involved in signal transduction.
Caveolins – a family of proteins, of which Caveolin-1 is principally responsible for the formation of caveolae.
Cavin-1 – a protein which binds onto Caveolin-1 which is essential for the formation of caveolae. Also known as PTRF (Polymerase 1 and Transcription Release Factor).
CCAAT/-enhancer-binding protein homologous protein (CHOP) – a protein involved in the progression of cells into apoptosis. If ER stress cannot be resolved by the UPR, CHOP stimulates the cell to undergo apoptosis.
CCNO (Cyclin O) – a protein which repairs damage to DNA in the form of substitution of uracil (normally only found in RNA) for thymine.
CD105 (Endoglin) – a membrane bound glycoprotein which is considered a marker for MSCs.
CD11b – a marker strongly expressed on monocytes and macrophages.
CD14 – a protein found on the surface of cells, particularly monocytes early in their development.
CD16 – a protein found on the surface of cells, particularly monocytes late in their development.
CD19 – a marker strongly associated with B lymphocytes.
CD34 – a marker of haematopoietic stem cells and endothelial cells.
CD45 – a protein common to all leukocyte lineages.
CD73 (Ecto-5'-nucleotidase) – a protein used as a marker of MSCs as well as certain lines of lymphocytes.
CD79α – a marker strongly associated with B lymphocytes.
CD90 (Thy-1) – a protein originally identified as a T lymphocyte marker, but which is now also considered to be an MSC marker.
Cdc25 (cell division cycle protein 25) – a group of proteins which regulate the progression through parts of the cell cycle (particularly entry into S phase and mitosis).
CDK – cyclin-dependent kinase – an enzyme which activates another protein by attaching a phosphate group to one of its amino acids. CDKs themselves are only active when associated with a cyclin protein. CDK-cyclin complexes are important regulators of the cell cycle.
CDKL3 (Cyclin-dependent Kinase-like Protein 3) - a protein with similarities to both CDKs and MAPKs. The proper function of CDKL3 in the cell has yet to be determined.
cDNA – complementary DNA – DNA made from mRNA using an enzyme such as reverse transcriptase. In eukaryotes, unlike the original gene in the chromosome, the cDNA contains no introns.
Cell – membrane bound bodies which form the basis of all living things.
Cell Biology – the study of processes which cells use to survive.
Cell Membrane – the outer boundary of the cell. It is composed of a double layer of phospholipids molecules arranged so that the water soluble ends face outwards while the water insoluble fatty ends face inwards. Embedded in this bilayer are various proteins involved in recognition of other substances and transfer of materials across the membrane.
Cell Cycle – the normal progression of development and reproduction through which eukaryotic cells pass. The cell cycle consists of mitosis and interphase, with interphase consisting of G1, S and G2 phases.
Cell Line – an immortal population of cells used in research derived from a tumour.
Centrifuge – a piece of laboratory equipment which separates components in a liquid medium based on their relative densities. Samples are loaded into tubes and spun at high speed. Denser materials sink to the bottom, while less dense materials float to the top. A guide to using a bench centrifuge can be found here.
Centrin – a family of proteins involved in the construction of the centrosome.
Centriole – a bundle of nine stacks of three microtubules arranged like a cartwheel. Two centrioles are found in each centrosome.
Centromere - the point in the middle of the chromosome where two chromatids join.
Centrosome – a subcellular body consisting of two centrioles embedded in a protein matrix. The centrosome is the site from which the mitotic spindle is constructed.
Cervicitis – inflammation of the cervix.
Chain Termination Sequencing – a method of determining the nucleotide sequence of a length of DNA using the PCR process and a mixture of labeled and unlabeled deoxyribonucleotides. If an unlabeled deoxyribonucleotide is incorporated into the DNA strand, extension continues uninterrupted. However if a labeled deoxyribonucleotide is incorporated, extension finishes. This generates a range of labeled DNA fragments of varying size which can be separated out using electrophoresis. More information on the use of fluorescent dyes in chain termination sequencing can be found here.
Chaperone Protein – a protein involved in the post-translational formation of proteins. Chaperones are involved in protein folding, the assembly of protein oligomers and the prevention of the formation of proteins into non-functional clumps.
Checkpoint – a point in the cell cycle where a cell must meet certain conditions before it can pass onto the next stage.
Chemotherapy – the use of drugs to treat diseases such as cancer.
Chimaera – a protein consisting of an amalgam of two or more different proteins. Named after the monster from Greek mythology.
Chitin - a complex polysaccharide composed of chains of N-acetylglucosamine. Chitin is a major structural component of the cell walls of fungi.
Chk1 (Checkpoint Kinase 1) – a protein involved in progression of cells through the G2/M checkpoint. Chk1 is activated by ATR in response to single stranded DNA damage. It phosphorylates and deactivates CDC25A and phosphorylates and activates Wee1, with the result that entry into mitosis is delayed until the damaged DNA is repaired.
Chk2 (Checkpoint Kinase 2) – a protein involved in progression of cells through the G2/M checkpoint. Chk2 is activated by ATM following double-stranded DNA damage. Activated Chk2 phosphorylates and deactivates CDC25A, resulting in a cell-cycle arrest until the DNA damage is repaired.
Chlamydia – a genus of pathogenic bacteria. Chlamydia is an intracellular parasite which can infect the urogenital tract (C. trachomatis), respiratory tract (C. pneumoniae) and eyes (C. trachomatis). C. muridarum is a species found in mice which has a similar pathology to C. trachomatis in humans.
Chlamydia-Induced Reactive Arthritis (CiReA) – reactive arthritis caused by an infection of the urogenital tract by Chlamydia spp.
Cholesterol – a steroid derivative which plays an important role in the structure of the cell membrane, as well as being a pre-cursor to steroid hormones and other compounds in the body.
Chondroblast – a cell which lays down cartilage tissue.
Chromatid – during S phase of the cell cycle, each chromosome is duplicated to give two chromatids. In the early phases of mitosis, these chromatids stay associated with each other, however they separate during anaphase.
Chondrocyte – a cell which makes and maintains the cartilaginous matrix.
Chromogen – a compound which changes colour, after undergoing a chemical reaction.
Chromosome – a length of DNA containing a long sequence of genes.
Chronic – a state of a disease characterized by lower-grade symptoms experienced over an extended period of time
Clathrin – a protein which forms cage-like structures around pockets of the cell membrane to form clathrin coated vesicles. These later lose the clathrins to form endosomes.
Clathrin Coated Vesicle (CCV) – an intracellular membrane bound body enclosed in a cage of clathrins formed as part pof the process of clathrin-mediated endocytosis.
Clathrin-Mediated Endocytosis (CME) – a method of endocytosis in which clathrins surround a pocket of cell membrane, eventually completely enclosing it in a cage-like structure which separates it from the rest of the membrane and forms a clathrin coated vesicle.
Cloning – the process of producing genetically identical individuals.
c-Myc – a transcription factor involved in the expression of a range of genes. In some cancers, mutations to the gene for c-Myc result in it being constantly expressed, leading to the overexpression of genes associated with cell proliferation.
Codon – a sequence of three nucleotide bases which encodes a particular amino acid in a peptide sequence.
Collagen - a protein found in the ECM.
CollIV (Collagen IV) – a protein which is a major structural component of the basement membrane.
Co-localisation – the close proximity of two structures.
Colony – a group of microbes growing on a culture plate. Typically, colonies arise from a single micro-organism, so all individuals in a colony can be considered clones of the original.
Comb – a plastic template used to cast loading wells into electrophoresis gels.
Competent Cells – bacteria capable of taking in DNA from their environment. Commercially, competent cells are usually defined as those capable of 106-108 transformations per μg of transforming DNA.
Complementary – in the structure of DNA, complementary nucleotide bases bind to each other exclusively eg. adenosine binds to thymidine, cytidine binds to guanidine.
Complex IV - cytochrome C oxidase – a protein found in the membranes of mitochondria which carries out part of the electron transport chain in cellular respiration. Complex IV can be used as a marker to demonstrate mitochondria in immunofluorescence.
Compound Heterozygosity – a form of inheritance where a condition only results from inheriting two separate alleles for the one gene (having only one of the alleles does not result in the condition).
Confluence – the degree to which cells in culture cover the bottom of the culture plate.
Confocal Microscopy – fluorescence microscopy in which the resolution is improved by focusing laser light of the excitation wavelength onto the specimen and passing the emitted light through a pinhole.
Conformation – the 3 dimensional shape of a large molecule like DNA or a protein.
Conjugate – a large molecule composed of two different molecules bound together.
Constitutive Endocytosis – a form of endocytosis in which materials are internalised continuously which is not triggered by a ligand producing a conformational change in its receptor.
Construct – an artificial length of DNA composed of DNA from different sources. For example, when plasmids are used as vectors, they often consist of the plasmid itself (often of bacterial origin), the gene to be inserted into the test cell, sequences which restriction enzymes target and genes for selection purposes (e.g. genes for antibiotic resistance).
Crohn's Disease – an inflammatory autoimmune condition which affects the gastrointestinal tract.
Cryomicrotome – a type of microtome which sections unfixed tissue which has been frozen.
C-Terminus – the end of the protein chain which has the carboxyl group exposed.
Culture – the practice of growing cells by providing them with the right temperature and nutrient requirements.
Cuvette – a small container made of glass, plastic or quartz crystal used to hold the substances tested in spectrophotometry.
Curcumin – a compound with anti-inflammatory properties derived from the spice turmeric.
Curdlan – a polysaccharide similar in structure to chemicals found in the cell walls of bacteria and fungi. Exposure to curdlan can trigger a strong inflammatory response.
Cut Site – the nucleotide sequence targeted by a restriction endonuclease.
Cyclin – a protein involved in the regulation of the cell cycle which binds to CDK and activates other proteins through phosphorylation.
Cytochemistry – the use of stains and dyes to demonstrate structures within cells.
Cytokine – a substance responsible for chemical communication between cells, particularly with respect to stimulating an immune response.
Cytokinesis – the separation of the two daughter cells during cell division.
Cytoplasm – the jelly-like substance outside the nucleus and bound by the cell membrane. It consists of the cytosol (cell liquid) and the organelles and other cellular components.
Cytoskeleton – a network of structural proteins which supports the cell and facilitates movement of components within it.
Cytotoxic – capable of killing cells.
Cytotoxic T Cell (TC Cell) – a type of T cell which can destroy pathogens or pathogen infected cells. Unlike NK cells, TC cells target specific disease agents and can provide long-lasting immunity.
Deacetylase – an enzyme which removes an acetyl group from a protein.
Demineralised Bone Matrix (DBM) – bone which has been chemically treated to remove the hard components of the tissue.
Denaturation – a disruption to the structure of a macromolecule caused by the breaking of hydrogen bonds. In DNA, denaturation results in the separation of the DNA strands, while in proteins it results in the loss of secondary and tertiary structure.
Dendrimer – a molecule with a branching tree-like structure made of repeating units called dendrons.
Dendritic Cell – a type of antigen presenting cell which processes antigens and presents them to cells of the adaptive immune system in order to generate a specific immune response.
Dendron – the function unit from which dendrimers are made.
Desensitisation – the process by which a cell lessens its response to an initial stimulus.
Destination Vector – a vector used in Gateway cloning which contains a promoter region and bacterial attachment sequences to allow recombination with entry vectors to create expression vectors. Destination vectors are tailored to create expression vectors suitable for introduction into specific host cells.
Development – the change in function of a cell, tissue, organ or organism as it ages.
Diabetes – a metabolic condition characterised by a disturbance in the normal control of glucose metabolism. The balance of glucose between the inside of the cell and the spaces outside (e.g. the blood) is maintained in part by the hormone insulin. In diabetes, this balance is disturbed, either by abnormal or insufficient production of insulin (Type I Diabetes) or a failure of cells to properly respond to insulin (Type II Diabetes). A third type of diabetes (Gestational Diabetes) occurs during pregnancy.
Dicer – an enzyme complex which cuts shRNA into siRNA.
Differentiation – the formation of specialised cells from generic pre-cursor or stem cells, or, in cell culture, telling apart two types of cell.
Dilution – reducing the concentration of a solution by adding more solvent.
Dimer - a molecule composed of two smaller subunits.
Diploid – having the normal complement of chromosomes. Somatic cells are diploid.
Disease - any disturbance to the normal functioning of the body.
DNA – deoxyribonucleic acid. DNA is composed of two antiparallel chains of nucleotides arranged in a double helix conformation. DNA resembles a twisted ladder, with the "rails" consisting of alternating phosphate groups and the 5-carbon sugar deoxyribose, and the "rungs" composed of pairs of nitrogenous bases joined by hydrogen bonding. It is capable of making copies of itself (with the aid of enzymes such as the DNA polymerases) and the order of its bases stores the information needed to manufacture proteins. More information on DNA can be found here.
DNA Ligase – an enzyme which joins DNA strands together by forming covalent bonds between phosphate groups and deoxyribose molecules in the "backbone" of the molecule.
DNA Polymerases – a group of enzymes which assemble the DNA strand using another DNA strand as a template.
DNA Probe – a short length of DNA complementary to a sequence found within a gene of interest.
Domain – a region within a protein molecule which has a particular function.
Donor Vector – a plasmid used in Gateway cloning which contains the bacterial attachment sequences. The donor vector "donates" the plasmid to create the entry vector.
Downregulation – a process in which a cell decreases the level of a substance within it in response to an external stimulus.
Downstream – sequences of amino acids in proteins are always written from the N-terminus to the C-terminus. If a sequence is said to be inserted "downstream" from a target gene, this means that it is attached after the C-terminus.
DpnI – a restriction endonuclease which targets methylated DNA, cutting the DNA strand into short, non-functional oligonucleotides.
Dysplasia – abnormal growth or development of tissue.
E2F Transcription Factors – a family of proteins which promote the expression of genes associated with S phase of the cell cycle.
E6 – an oncogene found in HPV.
E7 – an oncogene found in HPV.
E. coli – Escherichia coli – a gut bacterium sometimes called the "workhorse of molecular biology" because it is so commonly used in these laboratories.
Electromagnetic Radiation – a form of radiation which includes radio waves, microwaves, infra-red radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
Electrophoresis – a process by which an electric field is used to separate large molecules (e.g. DNA or proteins) on the basis of their size through a gel. More information on electrophoresis can be found here.
Electroporation - a method of introducing genetic material into cells involving the use of an electric field.
Embryo – the body formed by the division of the zygote and subsequent cell divisions.
Embryonic Stem Cells (ESC) – stem cells derived from the inner cell mass of the blastocyst.
Emission – in fluorescence, the wavelength emitted by a fluorophore following excitation.
Emulsion – a suspension of droplets consisting of surfactant molecules surrounding a hydrophobic substance. Emulsions are a way of solublising hydrophobic substances in water and may be used to deliver these substances into cells.
Endocytosis – the process by which cells take in substances from the external environment by surrounding them with pockets of the cell membrane.
Endoplasmic Reticulum – a sub-cellular membranous structure. The endoplasmic reticulum is described as either "rough" (containing ribosomes embedded in the membranes) or "smooth" (lacking ribosomes). The rough endoplasmic reticulum is the site of the majority of protein synthesis in eukaryotic cells, as well as protein folding and other post-translational modifications. The smooth endoplasmic reticulum is responsible for synthesis and metabolism of lipids (particularly steroids) and carbohydrates, as well as the maintenance of calcium balance and the metabolism of drugs.
Endoplasmic Reticulum (ER) Stress – a state in a cell caused by the accumulation of misfolded proteins in the endoplasmic reticulum to a level beyond which the cell's regulatory mechanisms can cope.
Endosome – an intracellular membrane-bound body formed as the result of endocytosis.
Endothelial Cell – a cell type which lines the inner surface of blood vessels.
Enteric – derived from the gastrointestinal tract.
Entry Vector – a plasmid created through Gateway cloning through the recombination of a gene of interest containing viral attachment sequences with a suitable donor vector containing bacterial attachment sequences.
Enzyme – a protein molecule which catalyses (helps along) a chemical reaction by lowering its activation energy. Enzymes do this by bringing molecules close together to join them together, or by undergoing a conformational change which breaks a bond.
Eosin – a dye which binds to the basic components of tissue and colours them pink.
Eosinophil – a type of granulocyte involved in allergic reactions and the response to parasitic infections.
Epidermal Growth Factor (EGF) – a small peptide which triggers cell growth and proliferation.
Epidermal Growth Factor Receptor (EGFR) – a type of tyrosine kinase receptor which binds to EGF.
Epidermis – the outer layer of the skin.
Epifluorescence – fluorescence observed after shining light of the appropriate excitation wavelength onto or through a specimen.
Epithelium – a type of tissue which lines a surface in the body.
Epitope – the portion of a protein which generates an immune response.
ERK (Extracellular Signal-regulated Kinase) – an alternative name for MAPK1 and MAPK2. ERK is sometimes used in place of MAPK.
Etoposide – a chemotherapy drug which inhibits the action of topoisomerase II.
Eukaryote – an organism whose cells containing membrane-bound organelles (eg. protists, fungi, plants and animals).
Excitation – in fluorescence, the wavelength needed to raise the electrons of a fluorophore to a higher energy state.
Exome – the proportion of the genome which is transcribed into mRNA for translation into proteins. In humans, the exome accounts for 1% of the total genome.
Exon – a region of coding DNA in a eukaryote gene. Exons are often separated by non-coding introns which must be removed from the mRNA transcribed from the gene before it can be translated into a protein.
Exponential Growth – growth of a population in which the number increases by an order of magnitude every generation. Cells which divide in two undergo an exponential growth phase where the population doubles with every generation.
Expression – the production of a protein under the instruction of a gene.
Expression Vector – a plasmid containing a promoter region which, when introduced into a suitable cell, expresses the protein product of a gene of interest within the plasmid.
Extension – "growing in length" – in PCR, the extension stage of the cycle is the one in which DNA Polymerase enzymes assemble a new DNA strand from nucleotides based on thetemplate strand.
Extracellular Matrix (ECM) – the non-cellular component of tissue.
Extravasation – penetration of cells through the endothelium and into the interior of blood vessels. Extravasation is an important step in cancer metastasis.
Eya1, 2 and 4 (Eyes Absent Homologs 1, 2 and 4) – proteins which promote the recruitment of DNA repair protein complexes to sites of DNA damage.
FACS (Fluorescence Assisted Cell Sorting) - a method which involves counting and sorting cells into subpopulations based on fluorescent labels attached to characteristic markers on their surfaces.
Fatty Liver Disease – a collection of medical conditions which lead to the replacement of normal liver tissue with adipose tissue.
Fertilisation – the fusion of two gametes to form a zygote.
Fibronectin - a protein found in the ECM.
Fibrosis – a disease state in which healthy tissue is replaced by non-functional acellular material.
Filter – in optics, a structure which only allows a limited range of wavelengths of light to pass through.
FigNL1 (Fidgetin-like Protein 1) – a protein involved in the DNA repair response which binds to RAD51.
Firefly – the common name given to the beetle Photinus pyralis which emits bioluminescence as part of its courtship display.
Fixation – a chemical treatment which forms crosslinks between peptide chains in proteins and prevents degradation.
Flow Cytometry – cell counting using lasers.
Fluorophore – a compound, usually attached to another molecule, which fluoresces.
Fluorescence – the emission of visible light by a substance after it has been excited by ultraviolet light.
Forward Scatter – in flow cytometry, forward scatter is the light which passes through a cell, and is indicative of the size of the cell.
Fragment – a piece of DNA.
Frameshift – a mutation which causes a change in the reading frame of a sequence of nucleotides.
Fungi - a group of eukaryotic organisms characterised by the presence of chitin in their cell walls. Fungi may be unicellular (yeasts) or multicellular (filamentous fungi). Fungi may be pathogenic, particularly in individuals with a compromised immune system.
Fusion Gene – a gene created by joining together two different genes. When these genes are from different sources, the fusion gene is sometimes called a chimaera, after the monster from greek mythology. Fusion genes code for fusion proteins.
Fusion Protein – a protein coded by a fusion gene. Fusion proteins are often generated to create "tagged" versions of a protein (eg. green fluorescent protein labels).
Fzr1 (Fizzy Related Protein 1) - a protein involved in the regulation of entry into mitosis. Sometimes known as Cdh1, however it is not the same as the membrane bound protein cadherin (also called Cdh1).
G1 Phase – the first "gap" phase of the cell cycle following cell division. During G1 phase, the cell carries out its normal functions and duplicates its organelles to replace those lost to the other cell during mitosis. If cells do not need to divide, they may enter a long term "resting" phase called G0 phase. If conditions are suitable and the cell passes the G1/S checkpoint, the cell may pass into S phase.
G2 Phase – the second "gap" phase of the cell cycle following S phase. During G2 phase the cell prepares for mitosis. At the G2/M checkpoint, the DNA is checked for errors before the cell commences mitosis.
Gametes - the sex cells which fuse during the process of fertilization.
γ-Tubulin – a protein component of the microtubules in the centrioles.
Gateway Cloning – a proprietary cloning method developed by the company Invitrogen which uses viral recombination systems based on the Lambda Phage.
Gating – in FACS analysis, the setting of parameters based on cell characteristics which determine the classification and sorting of cells into different sub-populations.
Gel – a semi-solid substance made by joining together smaller molecules (monomers) into larger molecules (polymers) in the presence of water. Gels are used as a supporting medium for electrophoresis. Examples of gels used for this are agarose and polyacrylamide.
Gene – the unit of inheritance. Genes are sections of DNA which code for the production of a particular protein or protein subunit.
Genome – the entire collection of genes in an organism.
Genotoxin – an agent which damages DNA.
Genotype – the genetic make-up of an organism ie. which versions or alleles of each gene that organism has.
Germline Mutation – a mutation in the genome which is contained in the gametes and therefore present from the point of fertilization. Germline mutations are present in all cells within an organism.
GFP – Green fluorescent protein – a protein derived from a jellyfish which emits green light when irradiated with ultraviolet light. GFP is commonly used as a tag to localise substances in molecular biology.
Glomerulus – a bundle of capillaries surrounded by the Bowman's capsule. At the glomerulus, small metabolites are lost from the bloodstream into the fluid within the Bowman's capsule. Larger molecules like proteins are retained in the blood.
Glucagon – a hormone produce by the α cells of the pancreas which stimulates cells to release glucose from storage molecules such as glycogen, raising levels of blood glucose.
Glucose-Regulated Protein 78 (grp78) - a 78kDa protein involved in the processing of misfolded proteins which protects the endoplasmic reticulum from their accumulation.
GLUT (Glucose Transporter Proteins) - a family of membrane bound proteins involved in the uptake of glucose by the cell.
Glutathione – a tripeptide consisting of the amino acids glutamine, cysteine and glycine.
Glycogen – a molecule used to store glucose in cells.
Glycoprotein – a molecule which contains both protein and carbohydrate components.
Glycosylation – attachment of sugar molecules to a protein.
Golgi Apparatus – a sub-cellular membranous structure involved in the packaging of proteins for secretion.
Granulocyte – a sub-population of myeloid leukocytes which show prominent inclusions in their cytoplasms. The three major groups of granulocytes are neutrophils, eosinophils and basophils.
Growth Medium – a mixture of nutrients and salts in a buffer liquid which supports the growth of cells (eukaryotic or bacterial). Growth media may be liquid or a semi-solid gel based on agar.
GST – Glutathione S-transferase – an enzyme which attaches glutathione molecules to other molecules. GST is used in the body to detoxify certain molecules by attaching the glutathione residue.
GWAS (Genome-Wide Association Study) – a method of analysis which involves comparing the frequency of SNPs in the genomes of individuals affected by a particular condition with that of individuals not affected by that condition.
Haematopoietic – giving rise to blood cells. Haematopoietic stem cell lines give rise to myeloid lines (which create red blood cells, granulocyte white blood cells and platelets) and lymphoid lines (which create lymphocytes).
Haematoxylin – a dye which binds to acid components of the tissue and colours them a deep blue colour.
Haemocytometer – a calibrated microscope slide used to perform cell counts. It contains a grid of known area above which is loaded the cell suspension to a known height (under a coverslip). The cells contained within the grid can then be counted and a number of cells per unit of volume calculated.
Haemoglobin – a protein which carries oxygen in the blood.
Hayflick Limit – a theoretical limit to the number of times a cell may divide, based on telomere shortening. For example, a typical embryonic cell is thought to be able to divide between 40 and 80 times before it reaches its Hayflick Limit.
HeLa Cells – a line of immortal cells grown in culture which were derived from a cervical tumour removed from a woman named Henrietta Lacks in 1951. They are one of the more widely used mammalian cell lines.
Haploid – having half the chromosome complement of normal cells. Gametes are haploid.
Heterodimer – a protein with quaternary structure consisting of two different subunits.
Heterogeneity – the degree of difference between individuals.
Heterozygous – the state in which an individual has two different alleles for a particular gene.
Histamine - a simple, nitrogenous molecule involved in initiating localised inflammatory responses.
Histochemistry – a laboratory discipline which involves studying thin sections of tissue which have been stained using various dyes.
Histone – a family of proteins intimately associated with DNA in the nucleus. DNA wraps around histones to form nucleosomes. This process assists in chromosomal packing and gene regulation.
Histone Acetyltransferase – an enzyme which transfers an acetyl group (-CH3COO-) to histones. This has the effect of unraveling the DNA from the histone and making it more freely available for transcription.
Histone Deacetylase – an enzyme which removes acetyl groups (-CH3COO-) from histones. This has the effect of allowing the DNA to wind more tightly around the histones, thus making it unavailable for transcription.
Histone Deacetylase Inhibitor – a group of compounds which inhibit the action of histone deacetylases, resulting in hyperacetylation of the histone tail and increased gene transcription.
HK-2 Cells – a cell line derived from proximal tubule cells.
Homodimer – a protein with quaternary structure consisting of two identical subunits.
Homotetramer – a protein with quaternary structure consisting of four identical subunits.
Homozygous – the state in which an individual has two copies of the same allele for a particular gene.
Hormone – a chemical messenger in the body of an organism. Hormones are generally made in one location and have their effect on cells in another location. Hormones generally have their effect by binding onto receptors on the outside of the cell.
Hormone Dependent Cancer – a type of cancer which is influenced (often stimulated) by the presence of a specific hormone.
Host – an organism which provides a place to live, feed and reproduce for another organism.
HRP (Horseradish Peroxidase) – an enzyme derived from horseradishes which catalyses the breakdown of hydrogen peroxide into water and oxygen. HRP is widely used as a detection agent, as it can catalyse reactions which transform chromogens into their coloured forms.
Human papillomavirus (HPV) – a virus which infects the cells of the skin and genital mucosa which is implicated in the development of warts and some cancers.
Hydrogel – a semi-solid material which incorporates water.
Hydroxyapatite – a salt consisting of calcium, magnesium and phosphate which forms a major component of the hard tissue in bone.
Hyperacetylation – the accumulation of acetyl groups on proteins caused by the selective inhibition of deacetylase enzymes.
Hyperproliferation – an abnormal increase in the rate of cell reproduction.
Hypertonic – describes a solution in which the concentration of solutes is higher than that found in cells.
Hypoplasia – reduced growth or development of tissue.
Hypotonic – describes a solution in which the concentration of solutes is lower than that found in cells.
Hypotrichosis – reduced growth of hair.
Immunity - protection from a disease causing agent.
Immunoblotting – a technique used to specifically identify proteins on a gel using labeled antibodies. Examples of immunoblotting include Western blots.
Immunofluorescence – a technique in which a cellular component is localised using an antibody attached to a fluorescent label
Immunogenicity – the degree to which an agent generates an immune response.
Immunoglobulins – the family of proteins which comprise the antibodies.
Immunohistochemistry – a technique in which enzyme labeled antibodies are used to demonstrate the presence of proteins and other structures in sections of tissue. Addition of a chromogenic substrate which creates a coloured precipitate in the presence of the enzyme label indicates the presence of the target molecule.
Induced Pluripotent Stem Cells (iPSC) – a form of adult stem cell produced by causing a differentiated cell to revert to a pluripotent state.
Inducible Nitric Oxide Synthetase (iNOS) – an enzyme which catalyses the production of nitric oxide in response to an external trigger, typically the presence of a pathogen.
Induction – the process of stimulating transformed cells to transcribe and translate inserted genes to generate proteins.
Incubation – a waiting period, to allow a reaction time to take place, or organisms time to grow and multiply.
Infection – a state caused by the presence of a living agent (eg. parasite, bacterium, fungus or virus).
Inflammation – a response by the body to damage or the presence of foreign objects. Inflammation is a complex process involving the interaction of many different substances. Some act as cytokines which attract specialised white blood cells to deal with the cause of the damage, while others may make blood vessels "leaky", releasing fluid into tissues to dilute the damaging agent.
Innate Immunity - protection from disease causing agents in a non-specific manner.
Insert - a length of DNA containing a gene which is inserted into a vector during ligation.
Insulin – a hormone produced by the β cells of the pancreas which stimulates cells to take up glucose, lowering the levels of glucose in the blood.
Integrins – a group of proteins which cells use to attach themselves to components of the ECM.
Interferon – a family of cytokines released in response to the presence of an infectious agent or cancer cell.
Interphase – the period between cell divisions during the cell cycle.
Intracellular – inside the cell.
Intravasation – a process in which a metastatic cancer cell penetrates the basement membrane and escapes into the circulatory system.
Intron – a region of non-coding DNA, often found interspersed between coding exons in eukaryotechromosomes. Introns must be removed from mRNA transcribed from a gene before it can be translated into protein.
In Vitro – "in glass" – experiments performed outside a living organism.
In Vivo – "in life" – experiments performed inside a living organism.
Isotonic – describes a solution in which the concentration of solutes is equal to that found in cells.
Kanamycin – an antibiotic used as a selective agent in culture media.
Karyorrhexis – the fragmentation of the cell nucleus during apoptosis.
Keratinocyte – a flattened cell found in the skin which produces the protein keratin.
Kidney – an organ which removes wastes from the blood into the urine.
Kilobase - a unit used to indicate the size of a fragment of DNA. 1 kilobase is equivalent to a sequence of DNA 1000 nucleotide bases long.
KIM-1 (Kidney Injury Molecule 1) – a protein which acts as a marker of kidney damage.
Kinase – an enzyme which attaches a phosphate group to a protein.
Kinetochore – a structure which attaches the chromosome to the spindle apparatus and assists in segregation of chromatids during mitosis.
Kinome – the collection of genes in a genome which code for kinases.
Ladder – a collection of bands in a gel produced by including a standard sample of DNA of known sizes. Used to estimate the size of DNA in test samples.
Lambda Phage – a virus which infects E. coli.
Laminin - a protein found in the ECM.
LB Medium – "Lysogeny Broth" (also "Luria Bertani" after its inventor) – a growth medium used to culture E. coli in the laboratory.
Lesion – any region of abnormal tissue in the body which may be caused by damage or infection.
Leucine Zipper – a region of a peptide characterized by alpha helices featuring leucine residues roughly every seven amino acids. Leucine zippers on two adjacent peptides allow the peptides to form dimers, with the sequences meshing together like two halves of a zipper.
Leukaemia – a condition characterised by the cancerous transformation of the stem cells which produce white blood cells.
Leukocyte – a white blood cell.
Ligand – something which binds to another material.
Ligand-Regulated Endocytosis – a mode of endocytosis which is triggered by a conformational change which occurs in a receptor when it binds to a ligand.
Ligation – a process by which the enzyme DNA Ligase joins together the sugar/phosphate backbones of two strands of DNA.
Linearised Plasmid – a plasmid that has been restricted so that it is no longer circular.
Lipid – biomolecules which are generally insoluble in water. Lipids are classified as fats (solid at room temperature) or oils (liquid at room temperature). Lipids have a role in storage of energy, as well as structural roles (lipids make up the bulk of cell membranes).
Lipoplex – a complex formed between a liposome and a nucleic acid – used to introduce genetic material into cells during transfection.
Lipopolysaccharide (LPS) – a compound consisting of both lipid and carbohydrate components which is derived from the outer membrane of certain bacteria. LPS is a potent stimulator of the inflammatory response.
Liposome – a small "bubble" composed of a phospholipid bilayer folded around to form a sphere. Liposomes may be used to carry substances into cells by merging with the cell membrane.
LNCaP Cells – a human cancer cell line derived from a prostate tumour.
Low Density Lipoprotein (LDL) – a transport protein which ferries the normally water insoluble lipids (eg. cholesterol) through the blood.
Luciferase – a family of enzymes found in bioluminescent organisms which catalyse the transformation of substrates (luciferins) into forms which emit light.
Luciferin – a group of chemical substrates which are acted upon by luciferases to create a form that emits light.
Luminescence – the emission of light.
Luminometer – a laboratory device which detects light emitted by a sample.
Lymphocyte – a type of white blood cell involved in the immune response. Lymphocytes are divided into a number of sub-types : Natural Killer (NK) cells, T Cells (comprising T Helper (TH) cells and Cytotoxic (TC) cells) and B cells.
Lysate – a "soup" of cellular components made by breaking apart (or "lysing") cells.
Lysis - disrupting or bursting cells.
Lysogenic Cycle – the stage of the life cycle of a virus in which the viral genome is incorporated into that of the host cell.
Lysosome – an intracellular body consisting of a membrane surrounding a solution of hydrolytic enzymes. Lysosomes are involved in the breakdown of foreign particles and some cellular components.
Lytic Cycle – the stage of the life cycle of a virus in which viral proteins are expressed which cause the cellular machinery to create virus particles.
Macrophage – type of white blood cell which aids immunity by engulfing foreign or damaging particles.
Major Histocompatibility Complex (MHC) – a complex of proteins present on the surface of cells which present self or non-self proteins to elements of the immune system. MHCs are involved in the recognition of and response to self and foreign materials by immune cells.
Malignant Tumour – a tumour which is capable of metastasis, also known as a cancerous tumour.
MAPK ("Mitogen Activated Protein Kinase") – a family of proteins involved in the MAPK signal transduction cascade which promotes the expression of transcription factors to encourage cell growth and division following stimulation by an external factor (eg. mitogens, osmotic stress, heat shock, inflammatory markers).
MAPK Scaffold Protein 1 – a protein found in association with caveolae which is involved in ERK signaling.
Marker – a chemical whose presence or absence may indicate a particular disease state or cellular process.
Master-mix - a stock solution sometimes used when working with very small volumes. A master-mix consists of all of the common reagents used in a reaction, so that instead of multiple deliveries of many small volumes, the operator can deliver one larger volume.
MCF-7 Cells – a line of oestrogen dependent human breast cancer cells.
Medium – a combination of salts and nutrients dissolved in a liquid (broth) or semi-solid material (plate) in which cells are grown.
Meiosis – the cell division process which results in the production of gametes. Unlike mitosis, meiosis results in haploid cells (which have half the chromosome complement of diploid cells).
MEK (MAPK ERK Kinase) - a protein involved in the MAPK signal transduction pathway. MEK is activated by the Ras/Raf complex and in turn phosphorylates and activates MAPK.
Melanoma – an aggressive cancer derived from the melanocytes in the skin.
Melanocyte – a pigment containing cell found in the bottom layer of the epidermis in the skin.
Mesenchymal Stem Cell (MSC) – a lineage of stem cells which give rise to osteoblasts, chondroblasts and adipocytes.
Metabolism – the sum total of all of the chemical reactions which occur within the cell.
Metaphase – the phase of mitosis characterised by the alignment of the chromosomes along the equator of the mitotic spindle.
Metastasis – the spread of cancerous cells from one part of the body to another, often resulting in the development of a secondary tumour.
Methylation – the process of attaching a methyl (-CH3) group to other molecules. Methylation of DNA is a process cells use to regulate the expression of genes.
Micelle – a small body within an emulsion consisting surfactant molecules surrounding a droplet of a hydrophobic substance.
Microenvironment - the conditions within a particular tissue.
Micronucleate – having a small, satellite nucleus as a result of chromosomal mis-segregation during mitosis.
Micropipette – a device used to accurately and precisely deliver small quantities (<1mL) of liquid. Directions for how to use micropipettes are found here.
Microtome – a device used to cut very thin sections of tissue.
Microtubule – a subcellular tubular structure made of protein which acts to support other structures within the cell.
Mini-prep – the alkaline lysis mini-plasmid preparation – a technique for recovering small volumes of plasmidDNA from bacteria.
miRNA (micro RNA) – short (~22 nucleotides) RNA molecules encoded by the cell's genome which are involved in post-transcriptional regulation of gene expression.
Mitochondrion – a sub-cellular organelle which carries out cellular respiration in eukaryotic cells.
Mitogen - an external agent which stimulates mitosis.
Mitosis – the process by which eukaryotic cells distribute chromosomes during cell division. Mitosis consists of prophase, prometaphase, metaphase, anaphase and telophase. The separation of the cells themselves is called cytokinesis.
Mitotic Spindle – a bundle of microtubules formed during mitosis which serves as the frame on which the chromosomes are separated.
Molecular Biology – the study of how chemical processes contribute to living systems. Molecular biology concentrates largely on the nature of DNA and proteins.
Motif – a characteristic region of a protein often involved in interactions with other proteins.
Monoblast – a stem cell precursor to the monocyte.
Monocyte – a type of circulating white blood cell which can differentiate into macrophages or dendritic cells.
Monolayer – a single layer of cells in culture.
Monopolar – having only one end.
Monosaccharide – a carbohydrate consisting of a single sugar molecule.
Morphology – the physical appearance of an object.
MP1 (MEK Partner 1) – a protein found in association with caveolae which is involved in ERK signaling.
Mucus – a substance rich in glycoproteins secreted by cells in the mucosa to provide protection and lubrication.
Mucus membrane – (also mucosa) – the wet surfaces of the body, such as those found lining the mouth, digestive and genital tracts.
Multicellular - an organism consiting of more than cell organised in functional systems.
Multipotent – capable of differentiating into cells from a specific lineage (eg. mesenchymal stem cells, haematopoietic stem cells).
Mutation – any change to the normal DNA sequence.
Myeloid - a lineage of blood cells which include the red blood cells, platelets, monocytes and granulocytes.
Native – the "normal" or "wild type" version of a gene, as opposed to one that contains a mutation.
Natural Killer (NK) Cells – part of the innate immune response, NK cells target body cells which have been changed either through infection by a disease agent or cancerous modifications. NK cells identify cells to attack through changes in the major histocompatibility (MHC) complex on their surfaces, and then destroy them by releasing cytotoxic materials.
Necrosis – uncontrolled cell death. Damaged cells break apart and released cellular components and agents which may trigger necrosis or inflammation in surrounding tissues.
Negative Control – a sample put through an experimental protocol as a test of that protocol. A negative control detects results which look positive in the absence of the variable which could cause a positive result (i.e. false positives).
Nephrin – a protein involved in the merging of GLUT rich intracellular vesicles with the cell membrane.
Nephron – the filtration unit of the kidney, consisting of the renal corpuscle and tubules.
Nephropathy – a disease state of the kidney.
Neutrophil – a form of granulocyte involved in the response to bacterial infection.
Non-polar Amino Acid – an amino acid with a mostly hydrocarbon side chain (ie. few or no oxygen or nitrogen atoms). Non-polar amino acids are normally hydrophobic.
Non-union – a type of bone injury where the ends of the fracture are not brought or kept close together, affecting the healing process.
N-Terminus – the end of a protein chain which has the amino group exposed.
Nuclear Localisation Sequence (NLS) – a sequence of amino acids which allows proteins to be transported to the nucleus.
Nucleic Acid - a type of macromolecule consisting of a chain of nucleotides. The sugar and phosphate groups in the nucleotides form a "backbone", while the nitrogenous bases jut off to the side. DNA and RNA are nucleic acids.
Nucleolus – a body found within the nucleus of cells involved in the manufacture of ribosomes.
Nucleoside – a combination of one of the nitrogenous bases (adenine, guanine, thymine, cytosine or uracil) and a five carbon (pentose) sugar – deoxyribose in DNA or ribose in RNA.
Nucleosome – a body formed by DNA coiling around histones.
Nucleotide – a chemical group consisting of a phosphate group, a 5-carbon sugar (either deoxyribose or ribose) and a nitrogenous base (either adenine, guanine, thymine, cytosine of uracil). Nucleotides form the basis of a strand of DNA.
Nucleus – a membrane bound body inside the cells of eukaryotes which contains the chromosomal DNA.
Obesity – a medical term describing a condition where body fat has accumulated to levels which may negatively impact on the health of the individual.
Oestrogens – a family of steroid-based hormones which regulate reproductive and related processes in females. An example of an oestrogen is oestradiol.
Oil Red O – a lipid soluble dye which is used to demonstrate fats and oils in cells and tissues.
Oligofectamine – a commercial preparation designed to deliver oligonucleotides into cells.
Oligomer – a molecule consisting of several subunits.
Oligonucleotide – a short sequence of nucleotide bases.
Oncogene – a gene which causes or is associated with the development of cancer.
Organelle – a sub-cellular component which carries out a particular task.
Osmosis - the diffusion of water across the cell membrane.
Osteoblast – a cell which creates bone tissue by laying down calcium deposits in the extracellular matrix.
PALB2 (Partner and Localiser of BRCA2) – a protein involved in the DNA repair response which binds to and assists in the intranuclear localization of BRCA2.
Pancreas – an abdominal organ which produces digestive enzymes and hormones such as insulin.
Pancreatic Islets – regions within the pancreas containing large numbers of β cells producing insulin.
Passage – to create a new culture of cells from an existing culture.
Pathogen – an agent which can cause disease.
Pathology – the study of disease processes.
PARP (Poly ADP Ribose Polymerase) – a protein involved in the response to DNA damage. PARP which has been cleaved by other enzymes is used as a marker of apoptosis.
PC3 Cells – a line of cells derived from an aggressive prostate cancer which have a faulty gene for Cavin-1.
Pdro – a protein found in association with caveolae which is involved in ERK signaling.
Pellet – the lower (usually solid) phase of a sample after centrifugation.
pENTR – a commercial plasmid that uses directed TOPO cloning and is compatible with Gateway cloning.
Peptide – a length of amino acids joined by peptide bonds.
Peptide Bond – the covalent linkage in protein chains between the amino group of one amino acid and the carboxyl group of the next.
Peripheral Blood - blood circulating in the blood vessels, rather than the organs and tissues. Peripheral blood is most easily accessed through the veins and surface capillaries.
PEST Sequence – a region of a peptide rich in the amino acids proline (P), glutamic acid (E), serine (S) and threonine (T). Proteins which have PEST sequences frequently have short half lives in the cell, indicating that the sequence may be involved in targeting the protein for degradation by structures like the proteasome.
p53 – a protein activated following DNA damage which binds to the DNA and promotes the expression of genes which regulate the cell cycle and initiate apoptosis.
pH – the degree of acidity (low pH) or alkalinity (high pH) of a solution.
Phagocyte – a specialist defense cell which removes foreign or damaging agents by engulfing them.
Phagocytosis – the process by which phagocytes engulf foreign particles.
Phalloidin – a compound derived from a species of mushroom which binds strongly to actin. When chemically combined with a fluorophore, phalloidin can be used to demonstrate the presence of actin in cells observed using fluorescence microscopy.
Phenotype – the outward expression of the genes of an organism, as they interact with the environment.
Phosphatase – an enzyme which removes a phosphate group from a compound.
Phosphatidylserine – an important phospholipid found in the cell membrane.
Phospholipid – an amphipathic compound consisting of one or two long, hydrophobic hydrocarbon "tails" attached to a hydrophilic phosphate containing "head". Phospholipids are important components of the cell membrane.
Phosphorylation – the process of attaching a phosphate group to another molecule.
Physiology – the processes which contribute to the maintenance of a constant internal environment.
Pilus (pl. pili) - small, fingerlike projections on the surface of bacterial cells. Pili are used by bacteria to transfer genetic information in the form of plasmids.
Plasma – the liquid (ie. non-cellular) component of blood.
Plasma Cell – a cell derived from B lymphocytes which generates antibodies.
Plasmid – a short, circular sequence of extra-chromosomal DNA. Some bacteria exchange plasmids between each other, and so plasmids are used as vectors to introduce new DNA into test cells.
Plasmin – a protease enzyme involved in the breakdown of blood clots and the detachment of cells from the ECM.
Plasminogen – the inactive precursor to plasmin. Plasminogen is protealytically cleaved by uPA to form the active plasmin.
Platelet – a small cellular fragment involved in the blood clotting process.
PLK1 (Polo-like kinase 1) – an enzyme found in a diverse range of animals involved in the regulation of normal mitosis. PLK1 attaches phosphate groups to serine or threonine residues in its target proteins, which has the effect of activating these proteins.
Pluripotent – capable of differentiating into any cell found in the body of a developing organism.
Podocin – a protein which forms a major part of the filtration structures in podocytes. The expression of this protein can be reduced in diabetic patients and may contribute to poor kidney function.
Podocyte – a cell which wraps extensions of its cytoplasm around the capillaries in the glomerulus and assists in the filtration of the blood.
Point Mutation – a change in the DNA involving very few nucleotides.
Polar Amino Acid – an amino acid with a side chain containing atoms which form polar covalent bonds (especially oxygen and nitrogen). Polar amino acids are often hydrophilic.
Polo-box Domain – the region of PLK1 which attaches to other proteins and localizes it within the cell.
Polymerase Chain Reaction (PCR) – a process used to amplify small quantities of DNA into amounts which can be used in experimentation. More information on PCR can be found here.
Polypeptide – a chain of many amino acids linked by peptide bonds.
Polyploid – having multiple sets of chromosomes.
Polysaccharide – a complex carbohydrate consisting of multiple sugar units.
Positive Control - a sample put through an experimental protocol as a test of that protocol. A positive control detects results which look negative, or a failure of the protocol to give the desired result (i.e. false negatives).
Post-translational Modification – changes to a protein following translation and folding. This may involve the attachment of chemical groups (eg. phosphorylation and glycosylation) or cuts in the peptide chain to create smaller protein subunits.
Primary Tumour – the lesion where a cancer originates.
Primer – in PCR, a short stretch of DNA to which the polymerase enzyme attaches and starts the process of DNA synthesis.
Prion – an infectious agent consisting of a single misfolded protein. The presence of a prion may cause other proteins to misfold, thus affecting their function.
Progenitor Cell – a cell which gives rise to another cell type.
Prognosis - the likelihood that a patient with a particular condition will survive.
Prokaryote – an organism whose cells contain no membrane-bound organelles (eg. bacteria, archaea).
Proliferation – multiplication of cells.
Prometaphase – the stage of mitosis characterised by the breakdown of the nuclear membrane and the attachment of the chromosomes to the mitotic spindle microtubules.
Promoter – a region in the DNA upstream of a gene which encourages the transcription and expression of that gene.
Prophase – the stage of mitosis characterised by the condensation of the chromosomes, the movement of the centrosomes to opposite ends of the cell and the commencement of the formation of the mitotic spindle.
Prophylaxis – a treatment used to prevent contracting a disease or other condition.
Prostate - a glandular organ found in the male uro-genital tract.
Protease - an enzyme which breaks down proteins.
Proteasome – a complex of proteins in the cell which acts to break down proteins, normally to remove unwanted or misfolded proteins.
Protein – a large biological molecule composed of a chain of smaller molecules called amino acids. Proteins perform a range of roles in the cell, including structure, catalysis of chemical reactions, recognition of substances and regulation of cellular processes. More information on proteins can be found here.
Proteinuria – a disease state where protein is found in high levels in the urine.
Protocol – a series of standard experimental procedures followed in the laboratory.
Proximal Tubules – structures within the kidney where important metabolites such as glucose and ions are reabsorbed back into the bloodstream from the urinary filtrate.
PTRF - Polymerase I and Transcript Release Factor, a protein which interacts with caveolins to create caveolae. Also known as Cavin-1.
p21 – a protein which regulates the cell cycle. p21 can stop cells from proliferating by inhibiting the action of cyclins which normally trigger progress through the cell cycle.
PUMA (p53 upregulated modulator of apoptosis) – a protein which triggers entry into apoptosis.
Punctate – having a "spotty" appearance.
Pyknosis – the small, dense appearance of cell nuclei during apoptosis.
qPCR (Quantitative PCR) – a method of PCR which allows the amount of original DNA presented to be measured.
RAD50 – an enzyme involved in the repair of DNA through recombination. RAD50 binds to BRCA1.
RAD51 – an enzyme involved in the repair of DNA through recombination. RAD50 binds to BRCA1 and BRCA2.
Radiotherapy – the use of ionising radiation to treat diseases such as cancer.
Raf ("Rapidly accerlerating fibrosarcoma") – a protein involved in the MAPK signal transduction pathway. Raf binds to and is phosphorylated by Ras and in turn phosphorylates and activates MEK.
Ras (derived from "Rat sarcoma) – a protein involved in the MAPK signal transduction pathway. Ras is activated by the binding of adaptor proteins to tyrosine kinase receptors and it binds to and activates Raf. The complex then phosphorylates MEK.
RB (Retinoblastoma Protein) – a tumour suppressor protein which halts progression through the cell cycle until the cell is ready to proceed.
Reading Frame – the manner in which codons are "read" by the ribosome. For example the sequence UACUCCAGGCGUGACCCC is read as UAC UCC AGG CGU GAC CCC. The deletion of a single base at position 7 shifts the reading frame from that point on, resulting in a different series of codons being "read" eg UAC UCC GAG GCG UGA CCC C.
Reactive Arthritis – a form of arthritis which occurs following an infection in either the urogenital or gastrointestinal tracts.
Receptor – a protein molecule found in the cytoplasm or embedded in the cell membrane which binds to a substance inside or outside the cell. When this substance is bound, a change in the receptor protein triggers changes in other proteins within the cell which then influences metabolic and regulatory processes inside the cell.
Renal Corpuscle – a sub-unit of the nephron consisting of the glomerulus and the Bowman's capsule.
Renilla – a genus of marine organism related to coral polyps which emits a blue bioluminescence.
Repressor – a region of DNA which inhibits the transcription of another gene.
Reporter Assay – a laboratory technique which quantifies the level of expression of a particular gene.
Resazurin – a compound used in viability studies on cells. Healthy cells reduce the non-fluorescent resazurin to resorufin, which fluoresces strongly under green light. The degree of this fluorescence can then be used as an indicator of the metabolic activity of the cells.
Residue - a term use to describe individual amino acids in a peptide chain.
Resolving Gel – the lower, larger region of an SDS-PAGE gel where individual protein bands are separated. Resolving gels are generally between 4% and 20% acrylamide and pH 8.8.
Restriction Digest – a technique in which an enzyme is used to cut the DNA at specific points. Restriction enzymes bind to specific sequences of nucleotides in the DNA and then cut the sugar-phosphate backbone of the molecule. More information on restriction digests can be found here.
Restriction Endonuclease – an enzyme which targets a particular region of DNA (either a sequence of nucleotides or a modification such as methylation) and cuts the DNA strand.
Rheumatoid Arthritis– an autoimmune disease which results from the body's immune system attacking the cartilage tissue in the joints.
Rheumatoid Factor – an autoantibody directed against a component of Immunoglobulin G (IgG) an important class of antibodies. The presence of rheumatoid factor in the blood is an important diagnostic feature of rheumatoid arthritis.
Ribosome - a body within the cell composed of protein and rRNA which carries out translation.
Ribonucleic Acid (RNA) – a nucleic acid which differs from DNA in that it contains the sugar ribose (instead of deoxyribose) and the nucleotide base uracil instead of thymine. RNA is usually single stranded, although it may double over on itself to create double-stranded regions and hairpin structures. The three major forms of RNA are mRNA (messenger) which is transcribed from the DNA and which carries the instructions for protein synthesis to the ribosome, tRNA (transfer) which bear the amino acids used in protein synthesis, and rRNA (ribosomal) which is found in the ribosome. Recently, attention has been directed to other forms of RNA which play a role in gene regulation : shRNA (short hairpin), siRNA (short interfering) and miRNA (micro).
RING Domain – a region of a protein commonly involved in the ubiquitination of other proteins.
RISC (RNA Induced Silencing Complex) – an enzyme complex involved in RNA interference. RISC associates with siRNA which then binds to a complementary sequence on mRNA. Wherever the RISC-siRNA complex binds, RISC cuts the mRNA strand, effectively silencing the gene which encoded the mRNA.
RMRP (RNA component of Mitochondrial RNA Processing endoribonuclease) – a gene which codes for an RNA molecule which forms part of the structure of RNase MRP. Mutations in the RMRP gene can lead to conditions such as anauxetic dysplasia and cartilage-hair hypoplasia.
RNA Interference – a method of gene regulation which targets the action of mRNA post-transcription and pre-translation.
RNase MRP (Mitochondrial RNA-processing Endoribonuclease) – an enzyme complex which incorporates the product of the RMRP gene. RNase MRP is believed to be involved in assisting in the replication of mitochondrial DNA, processing ribosomal RNA and regulation of the cell cycle.
Rough Endoplasmic Reticulum – a membranous network within the cell in which proteins are made.
SCD (Serine Containing Domain) – a region of a protein rich in serine residues. The hydroxyl (-OH) group on the side chain of serine allows it to be a site for phosphorylation in the protein.
SDS-PAGE – Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis – the process used to separate proteins on the basis of size.
Secondary Tumour – a tumour which arises in a different part of the body to the primary tumour, usually as a result of metastasis.
Selection Gene – a gene included in a plasmid to confer a property on transformed cells which can be used to encourage its growth while untransformed cells do not grow. An example is the ampicillin resistance gene. If bacteria are grown in a selective medium that contains the antibiotic ampicillin, only cells which have taken up a plasmid containing a gene which gives them resistance to ampicillin will survive.
Selective medium– a type of growth medium which only allows a certain organism to grow. For example, a culture medium may contain a specific antibiotic (e.g. Ampicillin). The only organisms which can grow in that medium are those which possess the gene for resistance to that antibiotic. This means that common contaminating organisms may not overwhelm the growth of the organisms we are trying to grow. In molecular biology, we often include an antibiotic resistance gene along with the gene we are trying to express. This means that only organisms which contain the resistance gene (along with the gene of interest) can grow, and therefore we can subculture from these populations confident that all of the organisms have been transformed.
Senescence – the process of ageing and the associated loss of function.
Septic Arthritis – a form of arthritis in which live pathogens can be cultured from fluid from the affected joints.
Serial Dilution – a technique in which a substance is diluted sequentially. A known volume is taken from the initial solution and placed into a known volume of diluent. This sample is mixed and the same sample volume is removed and transferred to the next volume of diluent, and so on.
Serum – the liquid (ie. non-cellular) component of clotted blood. Serum is plasma with the clotting factors removed.
SGLT (Sodium Dependent Glucose Transporter) – a family of proteins which reabsorb glucose from the fluid in the proximal tubules so that it can be returned to the bloodstream.
shRNA (short hairpin RNA) – a form of RNA from which is cut siRNA by the enzyme complex Dicer.
Side Chain – a chemical group attached to the central carbon of an amino acid. The structure of the side chain determines the identity and nature of the amino acid.
Side Scatter – in flow cytometry, side scatter is the light which reflects off the cell or its contents to the side, and is indicative of cell inclusions like granules.
Signal Transduction – the process of transferring a signal from outside the cell to inside the cell using specialised proteins.
Signal Transduction Cascades – the metabolic pathways through which an extracellular signal causes a response within the cell.
siRNA (short interfering RNA) - a form of RNA consisting of short (~22 nucleotides), double-stranded RNA cut from shRNA by the enzyme complex Dicer. siRNA associates with RISC and binds to complementary sequences on mRNA. The gene from which the mRNA is transcribed is silenced when RISC cuts it into non-translatable fragments. siRNA holds potential as a therapeutic agent as it can be used to inhibit the replication of viruses and prevent the expression of oncogenes.
Site-directed Mutagenesis – a technique used to produce versions of genes which are mutated so that the proteins they produce have one amino acid out of place.
SKG – a strain of laboratory mice derived from BALB/c mice with a mutation in the ZAP-70 gene which predisposes them to autoimmune conditions.
SNP (Single Nucleotide Polymorphism) – a change in the nucleotide sequence of a length of DNA involving the substitution of a single nucleotide.
Somatic Cells – cells in the body which are not gametes.
Somatic Mutation - a mutation which occurs following fertilization and so is not present in all cells within an organism.
S Phase – the stage of the cell cycle where DNA is duplicated in preparation for mitosis. The centrosome is also copied during S Phase.
Spectrophotometry – a process in which light of known intensity and wavelength is passed through a solution and used to estimate the levels of substances dissolved in that solution. Different materials absorb light of specific wavelength and the more of that substance present, the more light of that wavelength will be absorbed. If we measure the amount of light of a particular wavelength which passes through the substance, we can calculate the amount absorbed and therefore estimate the levels of the material absorbing the light.
Sphingolipid – a family of lipids found in the cell membrane which play a role in signal transduction and cell recognition.
Spondyloarthropathy (SpA) – any condition which causes inflammation of the joints of the spine.
Spondylometaepiphyseal Dysplasia – a family of conditions involving abnormal growth and development of the cartilage at the ends of bones in the spine and limbs.
Squamous Cell Carcinoma (SCC) – a cancer which affects squamous epithelium, a tissue which consists of layers of flattened cells (eg. the skin, the lining of the mouth).
Stacking Gel – the upper, smaller region of an SDS-PAGE gel containing the loading wells where proteins are initially sorted into discrete bands. Stacking gels are between 3.5-4% acrylamide and are at pH 6.8.
Stem Cell – a cell capable of proliferation which can give rise to other stem cells or to cells which can differentiate into mature functional cells.
Sterile – free of living organisms.
Steroid – a group of chemical compounds with a common structure based on a series of four interlocking carbon ring structures (called a sterane). Steroids differ from each other by the functional groups attached to this central structure. Examples of steroids include cholesterol and the hormones testosterone and oestradiol.
Stock Solution - a solution at a higher concentration than what is normally needed which is used for storage and to save the need to constantly make up new solutions from scratch. Stock solutions are diluted to create a working solution which is then used in laboratory procedures.
Strain – variety of a disease-causing agent. Some strains have more potential to cause disease than others.
Stroma – the component of a tissue which supports that tissue, rather than carrying out its functional role.
Subculture – to create a new culture of cells by transferring a sample of an existing culture into fresh culture media.
Substrate – the substance on which an enzyme acts.
Subunit – in a protein with quaternary structure, a subunit is one of the individual protein chains which make up the larger structure.
Supercompetent Cells – bacteria capable of taking in DNA from their environment with high efficiency. Commercially, supercompetent cells are usually defined as those capable of >109 transformations per μg of transforming DNA.
Supernatant – the upper (usually liquid) phase of a sample following centrifugation.
Surfactant – an amphipathic compound consisting of a long, hydrophobic hydrocarbon "tail" and a highly hydrophilic (sometimes charged) "head". Detergents are examples of surfactants, and surfactants can surround hydrophobic substances to make an emulsion, effectively solublising them.
Synergy – a situation where the effect of a combination of two agents is greater than if the individual effects of those agents were added together.
Synthetic Lethality – a principle by which researchers screen cancer cells with known faults in their function to find genes which, when knocked out in combination with the faults, causes cell death.
Systemic – affecting multiple parts of the body.
TAE – tris-acetate-EDTA – a buffer used to run DNA gels because it keeps the solution at a pH where all of the DNA is negatively charged.
TaqMan – a form of quantitative PCR in which DNA probes labeled with both a fluorescent dye and a quencher of that dye. As the DNA polymerase degrades the labeled probe, the fluorescent dye is released from the probe and is no longer quenched by the proximity of the quenching molecule. The rate at which this occurs is proportional to the amount of the original DNA template present.
Taq Polymerase – a DNA polymerase derived from the thermophilic bacterium Thermus aquaticus. Taq polymerase is used in PCR because it can operate at 72°C.
T Cell – a type of lymphocyte derived from the thymus. T cells are classified as cytotoxic (TC) or Helper (TH).
Telomerase – an enzyme which adds short sequences of DNA to the telomeres at the ends of the chromosomes, increasing the number of times a cell can divide.
Telomeres – regions on the end of chromosomes which are shortened by enzymatic action every time a celldivides. When no telomeres remain, the cell can no longer divide, giving rise to the Hayflick limit.
Telophase – the phase of mitosis characterised by the unwinding of the chromosomes and the reformation of the nuclear membrane and other organelles.
Template – a pattern from which a copy is made. In DNA replication, the order of nucleotides in the template strand is used to generated a new strand through complementary binding between nucleotides. In PCR, the template is the original DNA from which the PCR product is amplified.
Testosterone – the principal male sex hormone. Testosterone is an example of a steroid.
T Helper Cell – a type of lymphocyte which activates other cells using cytokines to generate an immune response.
Therapeutic – treatment aimed at curing or managing a disease or condition once it has been contracted.
Thermophilic – with an affinity or tolerance to heat.
Thrombolysis – the breakdown of blood clots.
Tissue – a collection of cells which work together to perform a function in the body.
Toll-Like Receptors (TLR) – a family of transmembrane proteins involved in the recognition of pathogens and the innate immune response.
Topoisomerase I – an enzyme which cuts and then religates the DNA strand. This enzyme is used as a recombination tool in some cloning systems (eg.pENTR).
Topoisomerase II - an enzyme which "untangles" DNA at the end of S phase by cutting the DNA strands, drawing the strands through the knot and joining them back together.
Totipotent – capable of given rise to any cell line in the developing embryo and associated tissues.
Transcription – the process of creating an mRNA molecule from a DNA template. More information on transcription can be found here.
Transcription Factor – an agent which promotes the transcription of genes which code for other proteins.
Transduction – the introduction of new genetic material into a cell using a viral vector.
Transfection – the transfer of genetic material into a mammalian cell.
Transferrin – a transport protein which ferries iron through the blood.
Transformation – the transfer of genetic material into a bacterial cell.
Translation – the process of creating a protein following information encoded in a mRNA molecule. More information on translation can be found here.
Transmembrane Protein – a protein which protrudes through the cell membrane. Ion channels and many receptors are transmembrane proteins.
Truncation – shortening by cutting off an end.
Tubulin – a protein which forms a major component of the cytoskeleton of the cell. Because it is found in relatively constant concentrations in most cells, tubulin is used as a loading control in SDS-PAGE and western blotting.
Tumour – a mass of tissue, often consisting of abnormal or undifferentiated cells. Tumours may be considered as benign or malignant.
Tyrosine Kinase Receptors – a family of proteins embedded in the cell membrane which are involved in signal transduction. When a ligand binds to their extra-cellular domains, they attach phosphate groups to proteins inside the cell which then trigger signal transduction cascades.
Ubiquitin – a protein which is attached to other proteins to mark them for a particular fate in the cell eg. degradation by the proteasome or transfer to another part of the cell.
Ultraviolet Light – electromagnetic radiation with a wavelength between 400nm and 10nm.
Unfolded Protein Response (UPR) – a cellular pathway stimulated by extreme ER stress.
Unicellular - an organism consisting of a single cell.
Upstream – sequences of amino acids in proteins are always written from the N-terminus to the C-terminus. If a sequence is said to be inserted "upstream" from a target gene, this means that it is attached before the N-terminus.
Urea – a nitrogenous compound excreted in the urine.
Urethritis – inflammation of the urethra.
Urine – a watery fluid made by the kidneys and used to release wastes like urea from the body.
uPA (Urokinase Plasminogen Activator) - a protease which cleaves plasminogen to form plasmin.
uPAR (uPA Receptor) - a protein found on the surface of cells which binds to uPA and helps in the localisation of its effects.
Upregulation - a cellular process in which the level of a substance is increased in response to an external stimulus.
Vaccine - a treatment aimed at artificially stimulating an immune response against a specific agent.
Vacuole – a membrane bound body found within cells used for storage.
Vector – something used to transfer DNA into a target cell.
Vesicle – a sub-cellular membrane-bound body.
Viability – the potential for cells to continual to grow and multiply.
Vital Staining – a technique where the viability of cells is assessed by their inability to permit the entry of water-soluble dyes. Cells which are stained by the dye are said to be non-viable as their membranes allow materials to freely cross.
Virus – an infectious agent consisting of genetic material (DNA or RNA) surrounded by a protein coat (capsid). Some viruses may have a lipid membrane derived from their host cell surrounding the capsid.
Virus-like Particle (VLP) – a particle which resembles the structure of a virus e.g. the capsid of a virus minus the genetic material.
Wart – a lesion characterised by the overgrowth of keratinocytes and caused by infection with certain strains of human papillomavirus (HPV).
Wavelength – the distance between two peaks in electromagnetic radiation. What we perceive as "colour" in the visible spectrum of light is the wavelength of that light.
Wee1 – a protein involved in regulating progression of cells through mitosis. Active (phosphorylated) Wee1 inhibits the action of Cdk1 which triggers entry into mitosis.
Well – a "hole" cast in a gel using a comb into which the sample is loaded for electrophoresis.
Wild Type – the native or "normal" form of a gene (ie. not mutated).
Working Solution - a solution used in laboratory procedures. Working solutions are made by diluting stock solutions.
Wound Healing Assay – a test of cellular migration which observes cells filling a gap in a monolayer following scratching the cells off the culture plate.
Xylene – a solvent which can dissolve paraffin wax.
Yeast – a unicellular fungus.
ZAP-70 – a gene which is mutated in SKG mice, leading to them being more prone to autoimmune conditions.
Z Stack – a virtual three dimensional image created by stacking together sequential confocal scans through a specimen.
Zygote – the single cell formed from the fusion of twogametes.
Zymogen – an inactive precursor molecule which is transformed into its active form following cleavage by a protease.