Biology Topics

Abiogenesis
Term applied by Thomas Huxley in 1870 to the theory that living matter may be produced from non-living.
Acidosis
A condition in which blood pH decreases, either for metabolic or respiratory reasons.
Actin
A protein making up the thin filaments of muscle and cytoskeleton of eukaryotic cells.
Adaptation
The way living things have changed in order for them to live and survive in their environment.
Adipocyte
An animal cell specialized for the storage of triacylglycerols.
ADP
Abbreviation of Adenosine Diphosphate.
Adulterants
Chemical impurities or substances that by law do not belong in a food, or pesticide.
Aerobe
An organism that uses oxygen as the terminal electron acceptor in respiration.
Aerobic
Requiring or occurring in the presence of oxygen.
Aerobiology
The study of the distribution of living organisms freely suspended in the atmosphere.
Aerodontalgia
A toothache brought on by a change in ambient pressure.
Aeroemphysema
A swelling condition caused by the formation of gas in the tissues of the body
Aero-Otitis Media
An inflammatory reaction of the middle ear resulting from a difference in pressure between the gas in the middle ear and the surrounding atmosphere.
Agent Orange
A toxic herbicide and defoliant used in the Vietnam conflict, containing 2,4,5-trichlorophen-oxyacetic acid and 2-4 dichlorophenoxyacetic acid with trace amounts of dioxin.
Agriculture
The science or art of farming.
Agronomics
The science of the distribution and management of land.
Agronomy
The science of soil management and crop production.
Air Pollution
The presence of contaminants or pollutant substances in the air that interfere with human health or welfare, or produce other harmful environmental effects.
Air Pollution Episode
A period of abnormally high concentration of air pollutants, often due to low winds and temperature inversion, that can cause illness and death.
Alcohol Fermentation
The anaerobic conversion of glucose to ethanol via anaerobic glycolysis.
Aldose
A simple sugar in which the carbonyl carbon atom is an aldehyde.
Algae
A large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms.
Algaecide
A chemical that when added to a solution prevents the growth of fungus and algae.
Algal Bloom
Sudden spurts of algae growth, which can affect water quality adversely and indicate potentially hazardous changes in local water chemistry.
Allergen
A substance that causes an allergic reaction in individuals sensitive to it.
Allosteric Activator
Any molecule which positively modulates the activity of an allosteric enzyme.
Allosteric Enzyme
A regulatory enzyme, with catalytic activity modulated by the noncovalent binding of a specific molecule at a site other than the active site.
Allosteric Site
The specific site on the surface of an allosteric enzyme molecule, distinct from the active site, to which a modulator molecule binds.
Ammonotelic
Organisms which excrete excess nitrogen in the form of ammonia.
Amphibolic Pathway
A metabolic pathway used in both catabolism and anabolism.
Amphipathic
Containing both polar and nonpolar domains.
Amylum
Another name for starch.
Anabolism
The phase of intermediary metabolism concerned with the energy-requiring biosynthesis of cell components from smaller precursors.
Anaerobe
An organism that lives without oxygen and uses another chemical species as a terminal electron acceptor.
Anaerobic
Occurring in the absence of air or oxygen.
Anaplerotic Reaction
An enzyme-catalyzed reaction that can replenish the supply of intermediates in a metabolic pathway, most commonly the citric acid cycle.
Anthocyanin
A family of pigments that give flowers, fruits, and leaves of some plants their red or blue colouring.
Antibiotic
An organic compound secreted by many species of microorganisms and fungi which is toxic to other species.
Antibody
A protein produced by the body′s immune system in response of an invading substance or organism.
Anticodon
A specific sequence of three nucleotides in a tRNA, complementary to a codon for an amino acid in a mRNA.
Antigen
Any molecule which causes the synthesis of a specific antibody in vertebrates.
Antiport
Cotransport of two solutes across a membrane in opposite directions.
Aquatic Ecotoxicity
The study of how chemicals affect the water environment and the organisms living there.
Arginine

C6H14N4O2

A semiessential or conditionally essential amino acid in mammals.

Arrhythmia
Absence of rhythm,eg in heart beat.
Asbestosis
Fibrosis of the lungs caused by inhalation of asbestos fibres.
ATP
Abbreviation of Adenosine Triphosphate.
ATP Synthase
An enzyme complex that forms ATP from ADP and phosphate during oxidative phosphorylation on the inner mitochondrial membrane or the bacterial plasma membrane, and during photophosphorylation in chloroplasts.
ATPase
An enzyme that hydrolyzes ATP to yield ADP and phosphate; usually coupled to some process requiring energy such as the sodium potassium ATPase.
Autophagosome
A vesicle which encloses material from inside the cytoplasm such as spent organelles or other structures and polymers to be degraded.
Autotroph
An organism that can synthesize its own complex molecules from simple carbon and nitrogen sources, such as CO2 and NH3.
Autotrophic Respiration
Respiration by photosynthetic organisms such as plants and algaes.
Auxin
A plant growth hormone.
Axon
The branched ending of the extended section of a neuron.
Back-Mutation
A mutation that causes a mutant gene to revert back to its wild-type genotype.
Bacteria
A group of small living organisms made of just one cell.
Bactericide
A pesticide used to control or destroy bacteria, typically in the home, schools, or hospitals.
Bacteriophage
A virus capable of replicating in a bacterial cell.
Balsam
Light oily aromatic extracts from trees which cure into resins.
Basal Metabolic Rate
The rate of oxygen consumption by an animal′s body at complete rest under fasting conditions.
Base Pair
Two nucleotides in nucleic acid chains that are paired by hydrogen bonding of their bases.
Bilayer Lipid Membrane
The structure found in most biological membranes, in which two layers of lipid molecules are so arranged that their hydrophobic parts interpenetrate, whereas their hydrophilic parts form the two surfaces of the bilayer.
Bile Salts
Amphipathic steroid derivatives with detergent properties, participating in digestion and absorption of lipids.
Biochemical Conversion
The use of enzymes and catalysts to change biological substances chemically to produce other products.
Biocide
Chemical substance capable of killing living organisms, usually in a selective way.
Biocytin
The molecule arising from covalent attachment of biotin to a Lys residue via an amide linkage.
Biodegradeable
Waste materials that can be broken down by organisms.
Biodiversity
The numbers and relative abundances of different genes, species, and ecosystems in a particular area.
Bioelectrochemistry
Electrochemistry of biological systems and biological compounds.
Biome
A grouping of similar plant and animal communities into broad landscape units that occur under similar environmental conditions.
Biopterin
An enzymatic cofactor derived from pterin and involved in certain oxidation-reduction reactions.
Biosensor
Either a sensor to detect a biological substance or a sensor which incorporates the use of biological molecules such as antibodies or enzymes.
Biosphere
The part of the Earth system comprising all ecosystems and living organisms in the atmosphere, on land, or in the oceans, including derived dead organic matter such as litter, soil organic matter, and oceanic detritus.
Biota
The animal and plant life of a given region.
Biotelemetry
The remote measuring and evaluation of life functions.
Biotin
Commonly known as vitamin H.
Blood Pressure
The pressure of blood in the main arteries in an animal.
Blood Vessel
A tube that carries blood around the body of an animal.
Bone
Primarily based on phosphate and carbonate.
Brain
An organ in the body which makes decisions and controls muscles in the body.
Brakish Water
Water having less salt than sea water, but undrinkable, having salinity values ranging from about 0.5 to 17 parts per thousand.
Buffer Solutions
Solutions that resist changes in their pH, even when small amounts of acid or base are added.
C10H16N2O8
Chemical formula for Ethylenediaminetetraacetic Acid.
C10H16N5O13P3
Chemical formula for Adenosine Triphosphate.
C19H22N2OS
Chemical formula for Acepromazine.
Calvin Cycle
The cyclic pathway used by plants to fix carbon dioxide and produce triose phosphates.
Cancer
A disease caused by mutations in the cells of an organism.
Capsid
The protein coat of a virus particle.
Carbohydrate
A class of organic compounds including sugars and starches.
Carbon Fixation Reactions
The light-independent enzymatic reactions involved in the synthesis of glucose from CO2, ATP, and NADPH.
Carbonate Water Hardness
Water hardness due to the presence of calcium and magnesium carbonates and bicarbonates.
Cardiovascular
Pertaining to the heart and the blood vessels.
Carnivore
An animal that eats only meat.
Carotenoids
Lipid-soluble photosynthetic pigments made up of isoprene units.
Catabolism
The phase of intermediary metabolism concerned with the energy-yielding degradation of nutrient molecules.
cDNA
Abbreviation of Complementary DNA.
Cell
The functional basic unit of life.
Cell Differentiation
Specialization of cell structure and function during embryonic growth and development.
Cell Membrane
The membrane around a cell.
Cell Wall
A rigid layer surrounding most bacterial cells, plant cells and some protists.
Centromer
Constricted region of a chromosome which serves as a site for microtubule attachment.
Chemotroph
An organism that obtains energy by metabolizing organic compounds derived from other organisms.
Chemotropism
Movement of a plant in response to chemicals.
Chlorination
The application of chlorine to drinking water, sewage, or industrial waste to disinfect or to oxidize undesirable compounds.
Chlorophylls
A family of green pigments functioning as receptors of light energy in photosynthesis.
Chloroplasts
Chlorophyll-containing photosynthetic organelles in some eukaryotic cells.
Chromatin
Dense complex consisting of double helix DNA and histones.
Chromosome
An organized structure of DNA and protein that is found in cells.
Circulatory System
A system which carries substances around the body.
Cistron
A unit of DNA or RNA corresponding to one gene.
Citric Acid Cycle
Another name for the Krebs Cycle.
Clathrin
A protein that plays a major role in the formation of coated vesicles.
Clone
Two or more organisms that have the same genes.
Cloning
The production of large numbers of identical DNA molecules or cells (or organisms) from a single ancestral DNA molecule, nucleus or cell.
Codons
Organic bases in sets of three that form the genetic code.
Coenzyme
An organic cofactor required for the action of certain enzymes.
Cofactor
An inorganic ion or a coenzyme required for enzyme activity.
Collagen
The most abundant protein in mammals.
Complementary DNA
A DNA, usually made by reverse transcriptase, which is complementary to given mRNA and used in cloning.
Compost
Plant remains which are allowed to rot.
Cone
A three-dimensional solid that rises to a single point at the top. A type of light-sensitive cell in the retina.
Conjugated Protein
A protein containing one or more prosthetic groups.
Cousteau, Jacques
French marine biologist, explorer, ecologist, filmmaker, photographer and researcher who studied the sea and all forms of life in water.
Cover Slip
Very thin square piece of glass or plastic placed over the specimen on a microscope slide.
Cristae
Infoldings of the inner mitochondrial membrane.
Cytochromes
Heme proteins serving as electron carriers in cellular respiration, photosynthesis, or other redox reactions.
Cytokinesis
The final separation of daughter cells following mitosis.
Cytoplasm
A jelly like material found in a living cell.
Cytoskeleton
The filamentous network providing structure, organization and motion to the cytoplasm: includes actin filaments, microtubules, and intermediate filaments.
Cytosol
The fluid content of the cytoplasm, excluding the membrane bound organelles.
Darwin, Charles
Darwin struck upon the theory of evolution.
Deamination
The enzymatic removal of amino groups from biomolecules such as amino acids or nucleotides.
Degenerate Code
The genetic code is degenerate because there are many instances in which different codons specify the same amino acid.
Deletion Mutation
A mutation resulting from the deletion of one or more nucleotides from a gene.
Denaturation
A loss of chemical function, usually due to some heat or chemically-induced structural change.
Dendrochronology
Tree-ring dating is the method of scientific dating based on the analysis of tree-ring growth patterns.
Deoxyribonucleic Acid
The biological macromolecule that carries the genetic information of all eukaryotic and prokaryotic cells.
Digestion
The breaking down of food.
Diploid
Having two sets of genetic information; describing a cell with two chromosomes of each type.
Disinfectant
A substance that kills or stops the growth of microbes.
Dissolved Oxygen
The amount of oxygen dissolved in a solvent (usually water).
DNA
The biological macromolecule that carries the genetic information of all eukaryotic and prokaryotic cells.
DNA Chimera
A DNA containing genetic information derived from two different DNA molecules.
DNA Cloning
The production of large numbers of identical DNA molecules or cells from a single ancestral DNA molecule, nucleus or cell.
DNA Library
A random collection of cloned DNA fragments designed to include all or most of the genome of a given organism.
DNA Ligase
An enzyme that creates a phosphodiester bond between the 3′ end of one DNA segment and the 5′ end of another.
DNA Polymerase
An enzyme that catalyzes template-dependent synthesis of DNA from its dNTP precursors.
DNA Replicase System
The entire complex of enzymes and specialized proteins required in biological DNA replication.
DNA Supercoiling
The coiling of DNA upon itself, into a more condensed structure.
DNA Transposition
The movement of a gene or set of genes from one site in the genome to another.
Double Helix
The natural coiled conformation of two complementary, antiparallel DNA chains by the formation of A-T and G-C base pairs.
Drinking Water
Water of sufficiently high quality that it can be consumed or used without risk of immediate or long term harm.
Ecology
The study of living things in their environment.
Ecosystem
A community of living things together with their environment.
Electrophysiology
The study of the electrical properties of living tissue.
Embryo
A young animal growing inside it′s mother or growing inside an egg.
Emulsion
A colloid formed from tiny liquid droplets suspended in another, immiscible liquid. E.g. Milk.
Endocytosis
Uptake of particles of food by the cell through invagination of the exterior side of the plasma membrane.
Endosome
A vesicle formed by fusion of several other vesicles which were imported into the cytoplasm by receptor mediated endocytosis.
Engineering and Physical Sciences Research Council
EPSRC funds research and postgraduate training in engineering and the physical sciences at universities and other organisations throughout the UK.
Enkephalin
Molecules produced naturally by the central nervous system to numb pain.
E-number
A code that refers to a food additive.
Enzyme
Protein or protein-based molecules that speed up chemical reactions occurring in living things.
Epitope
A portion of an antigenic macromolecule recognized and bound by a specific antibody.
EPSRC
Engineering and Physical Sciences Research Council
Essential Fatty Acids
The group of polyunsaturated fatty acids produced by plants, but not humans and are thus required in the human diet.
Eukaryotic Cell
A cell found in complex organisms that contains membrane-bound compartments in which specific metabolic activities take place.
Eutrophication
The absorption of excessive nutrients in a body of water, which causes a dense growth of plant life.
Evapotranspiration
The combined process of evaporation from the surface of the Earth and transpiration from vegetation.
Evolution
A theory that tries to explain the variety of all living things.
Excretion
The removal of waste substances from living things.
Exobiology
The study of biological processes that have or could have evolved away from the Earth.
Exocytosis
The fusion of an intracellular vesicle with the plasma membrane, releasing the vesicle contents to the extracellular space.
Exon
The segment of a eukaryotic gene that is transcribed into a protein or incorporated into the structure of an RNA.
Exonuclease
An enzyme that hydrolyzes phosphodiester bonds that are in the terminal positions of a nucleic acid.
Eye
An organ which is sensitive to light.
Facultative Anaerobe
An organism that can live in both aerobic and anaerobic conditions.
Fallopian Tube
A tube in female mammals which carries the egg cell from the ovary to the uterus.
Fat
A solid substance that is used by animals as a store of food energy.
Fatty Acid
Carboxylic acids with long hydrocarbon side chains.
Fermentation
A class of biochemical reactions that break down complex organic molecules into simpler materials.
Fertilisation
The joining of the male and female gametes.
Fertiliser
A substance added to soil to provide nutrients for plants.
Flagella
Long, rotating filaments enabling the bacteria to move in any direction.
Flagellum
A cell appendage used in propulsion.
Foetus
A young animal growing inside it′s mother, a foetus will have the same overall shape and parts of it′s parents.
Food Additive
A substance that is added to foods to improve colour or to make it last longer.
Food Chain
A list of organisms showing how each depends on another for food.
Food Web
A diagram showing how organisms depend on lots of other living things for food.
Fungicide
A substance that kill fungi.
Fungus
A simple organism, e.g moulds, mildews, mushrooms, and toadstools.
Gamete
A reproductive cell, in humans the male cell is a sperm the female cell is the ovum.
Gene
Part of a chromosome found inside the cells of living organisms.
Genetic Code
The set of triplet code words in mRNA or DNA, coding for the amino acids of proteins.
Genetic Engineering
A man-made method of altering the genes to change the characteristics of an organism.
Genetic Information
The hereditary information contained in a sequence of nucleotide bases.
Genetic Map
A diagram showing the position of specific genes along a chromosome relative to markers.
Genome
The complete set of genetic information of an organism.
Genomic Library
A random collection of cloned DNA fragments designed to include all or most of the genome of a given organism.
Genotype
The genetic information of an organism, as distinct from its physical expression (phenotype).
Geotropism
Movement of a plant in response to gravity.
Germination
The growth of a new plant from a seed.
Gestation Period
The length of gestation, the time from conception to birth. For humans this is 266 days.
Gill
An organ used by fish to get oxygen from water so that they can ′breathe′.
Gland
An organ in an organism which makes a particular substance.
Glutamate Receptors
Protein molecules that helps gate the flow of ions across a nerve cell′s membrane.
Glycogen
The storage polysaccharide of animals.
Gnotobiotics
Study of germ-free animals.
Grana
Stacks of thylakoids in chloroplasts.
Gum
Resinous or mucilaginous extracts from plants, shrubs, or trees.
Gum Acacia
Like gum arabic, but thought to be distinguishable from it; the dried resinous exudation of certain varieties of the acacia tree.

Gum Arabic
The dried exudation of certain varieties of the acacia tree.

Gum Benzoin
The dried resin of the tree Styrax benzoin.

Gum Lac
Dark-red resinous incrustation produced in certain trees by the insect Carteria lacca. When refined by certain processes it becomes shellac.

Gum Tragacanth
Dried gummy exhudation of the tree Astragalus gummifer and related speices.

Haeme
The iron-porphyrin prosthetic group of heme proteins.
Haemeprotein
A protein containing a haeme as a prosthetic group.
Haemoglobin
A haeme protein of erythrocytes which functions in oxygen transport.
Haploid
Having only one copy of each chromosome.
Haptotropism
Response of a plant to touch such as tendrils on a climbing plant wrapping themselves around other plants or supports.
Heart
A muscular organ that pumps blood through the body, a human heart is about the size of a fist.
Helicase
An enzyme that catalyzes the unwinding of strands in a DNA molecule before replication.
Heme
The iron-porphyrin prosthetic group of heme proteins.
Hemeprotein
A protein containing a heme as a prosthetic group.
Hemoglobin
A haeme protein of erythrocytes which functions in oxygen transport.
Herbivore
An animal that feeds on plants.
Heterotrophic Respiration
The conversion of organic matter to CO2 by organisms other than plants.
Heterozygous
Having two different alleles of the same gene.
Homologous Chromosome
One of two copies of a chromosome.
Homozygous
Having two identical alleles of the same gene.
Hormone
A molecule produced by endocrine glands that controls specific biological processes like growth and metabolism.
Human Biology
Lists all Human Biology topics in the Encyclopaedia
Hydrotropism
Movement of a plant in response to water.
Intermediary Metabolism
The enzyme-catalyzed reactions that extract chemical energy from nutrient molecules and utilize it to synthesize perform cell functions.
Intron
A sequence of nucleotides in a gene that is transcribed but not translated.
Iris
The pigmented fibrovascular tissue known as a stroma. It is the most forward portion of the eye and the only one seen on superficial inspection.
Isoenzyme
See Isozymes.
Isozymes
Two or more forms of an enzyme that catalyze the same reaction but differ from each other in their physical properties, such as amino acid sequence, substrate affinity, Vmax, tissue expression or regulatory properties.
Ketose
A simple monosaccharide in which the carbonyl group is a ketone.
Kidney
An organ in the body which is used for excretion.
Kinases
Enzymes that catalyze the phosphorylation of certain molecules using ATP as a phosphate source.
Krebs Cycle
A cyclic system of enzymatic reactions for the oxidation of acetyl residues to carbon dioxide.
Leading Strand
The DNA strand that, during replication, is synthesized in the same direction in which the replication fork moves.
Lipophilic
Refers to a substance′s solubility in fat.
Locus
The set of all points meeting some specified condition.
Lyases
Enzymes that catalyze the removal of a group from a molecule to form a double bond, or the addition of a group to a double bond.
Lysosomal Enzymes
Hydrolytic enzymes that can degrade any type of biological polymers.
Lysosome
An organelle that contains hydrolytic enzymes.
Macroscopic
Anything big enough to be seen with the naked eye.
Meiosis
Process of cellular division which produces egg or sperm cells.
Messenger RNA
Synthesized in the nucleus in a process called transcription using a DNA segment as a template.
Metabolism
A sequence of biochemical reactions that converts fuel molecules into energy used to drive other biological processes.
Metabolite
A compound produced by metabolic reactions.
Metalloprotein
A protein having a metal ion as its prosthetic group.
Micelle
An aggregate of amphipathic molecules in water, with the nonpolar portions in the interior and the polar portions at the exterior surface, exposed to water.
Microscope
An instrument to see objects too small for the naked eye.
Microscopic
Refers to objects that are too small for the unaided eye to see.
Microscopy
The investigation of microstructural elements using some type of microscope.
Mitosis
Process of cellular division which maintains the number of chromosomes.
m-RNA
Abbreviation of Messenger RNA.
Natural Heat
A term that has generally referred to the heat produced within the body, usually the heat produced by the heart and the circulatory system.
Neuron
A cell of nervous tissue specialized for transmission of a nerve impulse.
Neurotransmitter
A substance released from the axon terminal of a nerve cell which travels across the synaptic cleft to bind to a specific receptor.
Nitrogen Cycle
The exchange of nitrogen between animals and plants, in which plants convert urea or nitrates to protein, animals digest protein and excrete its nitrogen content an urea, which is taken up again by plants.
Nitrogen Fixation
Conversion of atmospheric nitrogen (N2) into a reduced, biologically available form.
Nitrogenase Complex
A system of enzymes capable of anaerobic reduction of atmospheric nitrogen to ammonia in the presence of ATP.
Nucleoid
In prokaryotes a region of the cell which contains chromosomal DNA.
Obligate Anaerobes
An organism that dies when exposed to oxygen.
Ocular
Pertaining to or in relation with the eye.
Oculogyric
Referring to movements of the eyes.
Oleoresin
A natural plant product that contains oil and resins, an example is turpentine.
Ovum
An unfertilized gamete, the female sex cell.
Oxidation-Reduction Reaction
A reaction in which electrons are transferred from a donor to an acceptor.
Oxygenases
Enzymes that catalyze reactions in which oxygen is introduced into an acceptor molecule.
Paracetamol
Another name for Acetaminophen.
Paraheliotropism
Movement of a plant in response to light.
Passive Diffusion
Diffusion of a molecule across a biological membrane via a protein transporter down a concentration gradient.
Pesticide
A chemical or biological agent that kills pests.
Phagosome
A vesicle which encloses material from coming from the outside of the cell by endocytosis .
Pharmacognosy
Identification, isolation, and characterization of biologically active substances in living things.
Pharmacology
The study of drugs, which includes determination of biological activity, biological effects, breakdown and synthesis, and delivery.
Phenotype
The observable characteristics of an organism.
Phosphorylation
Formation of a phosphate derivative of a biomolecule.
Photochemical Reaction Centre
The part of a photosynthetic complex where the energy of an absorbed photon causes charge separation, initiating electron transfer.
Photophosphorylation
The enzymatic formation of ATP from ADP coupled to the light-dependent transfer of electrons from water in photosynthetic cells.
Photoreduction
The light-induced reduction of NADP in photosynthetic cells.
Photosynthesis
Process by which green plants convert light to energy by transforming carbon dioxide and water into carbohydrates.
Phototroph
An organism that can use the energy of light to synthesize its own fuels from simple molecules such as carbon dioxide, oxygen, and water.
Phytochemicals
Materials extracted from plant tissue.
Phytochemistry
The study of substances found in plants.
Phytoplankton
The plant forms of plankton.
Plankton
Aquatic organisms that drift or swim weakly.
Plasma Membrane
The exterior membrane surrounding the cytoplasm of a cell.
Plasma Proteins
The proteins present in blood plasma.
Plastid
In plants, a self-replicating organelle; may differentiate into a chloroplast.
Platelets
Small, enucleated cells that initiate blood clotting which arise from megakaryocytes in the bone marrow.
PM10
Particles measuring 10µm or less.
PM2.5
Particles measuring 2.5µm or less.
Potable Water
Another name for drinking water.
Prebiotic
Related to the period before life appears on a planet.
Prokaryote
A unicellular organism with a single chromosome, no nuclear envelope, and no membrane-bounded organelles.
Prokaryotic Cell
A prokaryotic cell has no nucleus and no cellular organelles.
Protein Kinases
Enzymes that phosphorylate certain amino acid residues (most often Ser, Thr, or Tyr) in specific proteins.
Protein Targetting
The process by which newly synthesized proteins are sorted and transported to their proper locations in the cell.
Protist
A diverse group of eukaryotic microorganisms.
Proton-Motive Force
The electrochemical potential inherent in a trans-membrane H+ concentration gradient.
Quadrat
A square frame with sides of 1 metre which is used to enable the sampling of organisms.
Reaction Time
The time taken to react to an event.
Receptor Site
A molecule or surface in a cell that recognizes and binds to a specific messenger molecule, leading to a biological response.
Regulatory Enzyme
An enzyme which can be regulated by allosteric mechanisms or by covalent modification.
Regulatory Sequence
A DNA sequence involved in regulating the expression of a gene: a promoter or operator.
Respiration
The process of generating energy from the oxidation of organic compounds, with the electrons transferred to oxygen as the final electron acceptor.
Reulatory Gene
A gene that gives rise to a product involved in the regulation of the expression of another gene.
RF Radiation Hazard
A health hazard caused by exposure to electromagnetic radiation or highenergy particles.
Ribonucleic Acid
One of the three major macromolecules, along with DNA and proteins, that are essential for all known forms of life.
Ribosomal RNA
A basic building block for ribosomes.
Ribosome
Site of protein synthesis.
r-RNA
Abbreviation of Ribosomal RNA.
Satellite DNA
Highly repeated, nontranslated segments of DNA whose function is not clear.
Saturated Fatty Acid
A fatty acid containing no double bonds.
Secondary Metabolism
Pathways that lead to specialized products, not found in every living cell.
Silent Mutation
A mutation in a gene that causes no detectable change in the biological characteristics of the gene product.
Simple Protein
A protein yielding only amino acids on hydrolysis.
Sinus
A hollow or cavity; a recess or pocket.
Sol
A colloid with solid particles suspended in a liquid.
Somatic Cells
Body cells. All the cells except the germ-line cells.
Sour Water
Waste waters containing fetid materials, usually sulphur compounds.
Southern Blot
A DNA hybridization procedure in which specific DNA fragments are detected in a mixture by means of a complementary, labelled nucleic acid probe.
Starch
A polysaccharide used by plants to stockpile glucose molecules.
Sterols
A class of lipids containing the steroid nucleus.
Stroma
The space and aqueous solution enclosed within the inner membrane of a chloroplast.
Svedberg
A unit of measure of the rate at which a particle sediments in a centrifugal field.
Thermotropism
Movement of a plant in response to temperature.
Thylakoid
Closed cisterna, or disc, formed by the pigment-bearing internal membranes of chloroplasts.
Tissue Culture
Method by which cells derived from multi-cellular organisms are grown in liquid media.
Toxic Vapours
Vapors emitted by a substance that can do bodily harm.
Toxins
Proteins produced by some organisms and toxic to some other species.
Transfer RNA
A form of RNA that binds to amino acids.
Translational Control
The regulation of the rate of a protein′s synthesis by regulation of the rate of translocation of the ribosome.
Translational Repressor
A repressor that blocks translation of a mRNA.
Transpiration
Passage of water from the roots of a plant to the atmosphere via the vascular system and the stomata of the leaves.
Transporters
Proteins that span a membrane and transport specific molecules across the membrane.
Transposition
The movement of a gene or set of genes from one site in the genome to another.
Transposon
A segment of DNA that can move from one position in the genome to another.
Tricarboxylic Cycle
Another name for the Krebs Cycle.
Triglyceride
An ester of glycerol and three fatty acids.
Triose
A simple sugar with a backbone containing three carbon atoms.
t-RNA
Abbreviation of Transfer RNA.
Tropism
The movement of a plant in response to a stimulus.
Turnover Number
The number of times an enzyme molecule transforms a substrate molecule per second.
Units
Lists all Units topics in the Encyclopaedia
Unsaturated Fat
A lipid containing one or more carbon-carbon double bonds.
Unsaturated Fatty Acid
A fatty acid containing one or more double bonds.
Urea Cycle
A metabolic pathway in vertebrates, for the synthesis of urea from amino groups and carbon dioxide.
Ureotelic
Organisms which excrete excess nitrogen in the form of urea.
Uricotelic
Organisms which excrete excess nitrogen in the form of uric acid.
Urine
Liquid waste that leaves the body, compostition 96% water, 2% urea, 2% salts.
Viral Vector
A viral DNA altered so that it can act as a vector for recombinant DNA.
Virion
A single virus particle.
Vital Heat
A term that has generally referred to the heat produced within the body, usually the heat produced by the heart and the circulatory system.
Whey
The liquid which remains after milk is curdled, usually in the process of cheese-making.
Wild Type
The normal (non-mutated) phenotype.
Wind Chill Index
The calculation of temperature that takes into consideration the effects of wind and temperature on the human body.
Yeast
A type of fungus that is used in baking and brewing.
Zooplankton
A broad categorisation spanning a range of organism sizes that includes both small protozoans and large metazoans.
Zygote
A single living cell that results when a female egg is fertilized by sperm.
Zymogen
An inactive precursor of an enzyme.

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