Biology Glossary

What are abiotic factors?
Non living conditions in a habitit
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What is activation energy?
The energy required to initiate a reaction
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What is the active site?
Area of an enzyme with a shape complementary to a specific substrate, allowing the enzyme to bind a substrate with specificity
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What is active transport?
Movement of particles across a plasma membrane against a concentration gradient. Energy is required
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What is adenosine diphosphate (ADP)?
A nucleotide composed of a nitrogenous base (adenine), a pentose sugar and 2 phosphate groups. Formed by the hydrolysis of ATP, releasing a phosphate ion and energy
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What is adenosine triphosphate (ATP)?
A nucleotide composed of a nirogenous base (adenine), a pentose sugar and 3 phosphate groups. The universal energy currency for cells
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What are agglutinins?
Chemicals (antibodies) that cause pathogens to clump together so they are easier for phagocytes to engulf an digest
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What are alleles?
Different versions of the same gene?
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What are amino acids?
Monomers used to build polypeptides and thus proteins
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What is anabolism (anabolic)?
Reactions of metabolism that construct molecules from smaller units. These reactions require energy from the hydrolysis of ATP
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What are analogous structures?
Structures that have adapted to perform the same functions but have s different origin
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What is anaphase?
The 3rd stage of mitosis when chromatids are separated to opposite poles of the cell
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What is antibiotic - resistant bacteria?
Bacteria that undergo mutation to become resistant to an antibiotic and then survives to increase in numbers
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What are antibiotics?
A chemical or compound that kills or inhibits the growth of bacteria
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What are antibodies?
Y-shaped glycoproteins made by B cells of the immune system in response to the presence of an antigen
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What is an antigen?
Identifying chemicals on the surface of a cell that triggers an immune system
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What is an antigen - antibody complex?
The complex formed when an antibody bins to an antigen
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What is an anti - presenting cell(APC)?
A cell that displays foreign antigens complexed with major histcompatibility complexes on their surface
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What is a antisense strand?
The strand of DNA that runs 3` to 5` and is complementary to the sense strand. It acts as a template strand during transcription
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What are anti - toxins?
Chemicals (antibodies) that bind to toxins produced by pathogens so they are no longer have an effect
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What is an apoplast?
The cell walls and intercellular spaces of plant cells
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What is a apoplast route?
Movement of substances through the cell walls and cell spaces by diffusion and into cytoplasm by active transport
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What is arrhythmia?
An abnormal rhythm of heart.
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What are artefacts?
Objects or structures seen through a microscope that have been created during the processing of the specimen
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What is artificial active immunity?
Immunity which results from exposure to a safe form of a pathogen, for example, by vaccination
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What is artificial passive immunity?
Immunity which results from the administration of antibodies from another animal against a dangerous pathogen
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What is asexual reproduction?
The production of genetically identical offspring from a single parent
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What are assimilates?
The products of photosynthesis that are transported around a plant, e.g. Sucrose
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What are atrial fibrillation?
An abnormal rhythm of the heart when the atria beat very fast and incompletely
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What is atrio - ventricular node (AVN)?
Stimulates the ventricles to contract after imposing a slight delay to ensure atrial contraction is complete
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What is autoimmune disease?
A condition or illness resulting from an autoimmune response
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What is autoimmune response?
A response when the immune system acts against its own cells and destroys healthy tissue in the body
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What are autotrophic?
Organisms that acquire nutrients by photosynthesis
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What are B effector cells?
B lymphocytes that divide to form plasma cell clones
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What are B lymphocytes (B cells)?
Lymphocytes which mature in the bone marrow and that are involved in the production of antibodies
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What are B memory cell?
B lymphocytes that live a long time and provide immunological memory of the antibody needed against a specific antigen
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What is belt transect?
2 parallel lines are marked along the ground and samples are taken of the area at specified points
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What is Benedict's reagent?
An alkaline solution of copper sulfate used in the chemical tests for reducing sugars. A brick-red precipitate indicates a positive result
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What is a beta pleated sheet?
Sheet - like secondary structure of proteins
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What is binomial nomenclature?
The scientific naming of a species with a Latin name made of 2 parts - the first indicating the genus and the second the species
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What is biodiversity?
The variety of living organisms pesent in the area
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What is a buret test?
The chemical test for proteins; peptide bonds form violet coloured complexes with copper ions in alkaline solutions
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What is the Bohr effect?
The effect of carbon dioxide concentration on the uptake and release of oxygen by haemoglobin
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What is bradycardia?
A slow heart rhythm of below 60 beats per minute
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What is breathing rate?
The number of breaths (inhalation and exhalation) taken per minute
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What is bulk transport?
A form of active transport where large molecules or whole bacterial cells are moved into or out of a cell by endocytosis or exocytosis
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What is bundle of his?
Conducting tissue composed of purkyne fibres that passes through the septum of the heart
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What are callose?
A polysaccharide containing B 1-3 linkages and B 1-6 linkages between the glucose monomers that is important in the plant response to infection
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What is carbaminohaemoglobin?
The compound formed when carbon dioxide combines with haemoglobin
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What are carbohydrates?
Organic polymers composed of the elements carbon, hydrogen and oxygen in the ratio. Also known as saccharides or sugars
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What are carbonic anhydrase?
Enzyme which catalyses the reversible reaction between carbon dioxide and water to form carbonic acid
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What is cardiac cycle?
The events of a single heartbeat , composed of diastole and systole
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What are carrier proteins?
Membrane proteins that play a part in the transport of substances through a membrane
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What is cartilage?
Strong, flexible connective tissue found in many areas of the bodies of humans and other animals
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What are catabolism (catabolic)?
Reactions of metabolism that break molecules down into smaller units. These reactions release energy
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What is catalase?
An wnzyme that catalyses the breakdownn of hydrogen peroxide
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What is the cell cycle?
The highly ordered sequence of events that takes place in a cell, resulting in division of the nucleus and the formation of two genetically identical daughter cell
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What is cell signalling?
A complex system of intercellular communication
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What is cellulose?
A polysaccharide formed from beta glucose molecules where alternate beta glucose molecules are turned upside down. It is unable to coil or form branches but makes hydrogen bonds with other cellulose molecules to produce strong and insoluble fibres.
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What is a cell wall?
A strong but flexible layer that surrounds some cell types. Made from cellulose
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What are centrioles?
Component of the cytoskeleton of most eukaryotic cells, composed of microtubules
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What is a centromere?
Region at which 2 chromatids are held together
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What are channel proteins?
Membrane proteins that provide a hydrophilic channel through membrane
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What are checkpoints?
Control mechanisms of the cell cycle
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What is chiasmata?
Sections of DNA, which became entangled during crossing over, break and rejoin in Anaphase 1 of meiosis sometimes resulting in an exchange of DNA between bivalent chromosomes, forming recombinant chromatids and providing genetic variation
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What is a chloride shift?
The movement of chloride ions into the red blood cells as hydrogen ions move out to maintain the electrochemical equilibrium
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What are chloroplasts?
Organelles that are responsible for photosynthesis in plant cells. Contain chlorophyll pigments, which are the site of the light reactions of photosynthesis
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What are chromatids?
2 identical copies of DNA (a chromosome) held together at a centromere
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What is chromatin?
Uncondensed DNA in a complex with histones
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What are chromosomes?
Structures of condensed and coiled DNA in the form of chromatin. Chromosomes become visible under the light microscope when cells are preparing to divide
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What are circulatory cells?
The transport system of an animal
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What is clonal expansion?
The mass proliferation of antibody-producing cells by clonal selection
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What is clonal selection?
The theory that exposure to a specific antigen selectively stimulates the proliferation of the cell with the appropriate antibody to form numerous clones of these specific antibody-forming clones (clonal expansion)
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What is the closed circulatory system?
A circulatory system where the blood is enclosed in blood vessels and does not come into direct contact with the cells of the body beyond the blood vessels
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What is Clostridium difficile (C.difficile)
A species of Gram positive bacteria that is resistant to most antibiotics
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What is a codon?
A 3 base sequence of DNA or RNA that codes for an amino acid
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What are cofactors?
Non protein components necessary for the effective functioning of an enzyme
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What is the cohesion - tension theory?
The best current model explaining the movement of water through a plant during transpiration
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What are communicable diseases?
Diseases that can be passed from one organism to another, of the same or different species
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What is a community?
All the populations of living organisms in a particular habitat
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What are companion cells?
The active cells found next to sieve tubes elements that supply the phloem vessels with all of their metabolic needs.
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What is a competitive inhibitor?
An inhibitor that competes with a substrate to bind to active site on an enzyme
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What is complementary base pairing?
Specific hydrogen bonding between nucleic acid bases. Adenine binds to thymine or uracil and cytosine binds to guanine
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What is a compound light microsope?
Has 2 lenses. Objective lens, which is placed near to the specimen and the eyepiece lens, through which the specimen is viewed
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What is condensation reaction?
A reaction between 2 molecules resulting in the formation of a larger molecule and the release of a water molecule. Opposite is a hydrolysis reaction
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What is continuous variation?
A characteristic that can take any value within a range, e.g. height
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What is contrast?
Staining or treating specific cell components so that they are visable compared to untreated components
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What is convergent evolution?
Organisms evolve similarities because the organisms adapt to similar environments or other selection pressures
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What is correlation coefficient?
Statistical test used to consider the relationship between 2 sets of data
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What is a countercurrent exchange system?
A system for exchanging materials or heat when the 2 different components flow in the opposite directions past each other
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What is a counterstain?
Application of 2nd stain with a contrasting colour to sample for microscopy
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What are cytokines?
Cell-signalling molecules produced by mas cells in damaged tissues that attract phagocytes to the site of infection or inflammation
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What is cytokinesis?
Cell division stage in the mitotic phase of the cell cycle that results in the production of 2 identical daughter cells
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What is cytolysis?
The bursting of an animal cell caused by increasing hydrostatic pressure as water enters by osmosis
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What is a cytoplasm?
Internal fluid of cells, composed of cytosol (water, salts and organic molecules), organelles and cytoskeleton
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What is denatured?
Change in tertiary structure of a protein or enzyme, resulting in loss of normal function
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What is deoxyribonucleicacid (DNA)?
The molecule responsible for the storage of genetic information
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What is diastole?
The stage of the cariac cycle in which the heart relaxes and the atria and then the ventricles fill with blood
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What are dicotyledonous plants (dicots)?
Plants that produce seeds containing 2 cotyledons, which act as food stores for the developing embryo and form first leaves then seed germinates
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What is differential staining?
Using specific stains to distinguish different types of cell
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What is differentiation?
The process of a cell becoming differentiated. Involves the selective expression of genes in a cell's genome
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What is diploid?
Normal chromosome number; 2 chromosomes of each type - 1 inherited from each parent
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What does disaccharide mean?
A molecule comprising 2 monosaccharides, joined togetherr by a glycosidic bond
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What is discontinuous variation?
A characteristic that can only result in certain discrete values, for example, blood type
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What is divergent evolution?
Species diverge over time into 2 different species, resulting in a new species becoming less like the original one
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What is DNA helicase?
Enzyme that catalyses the unwinding and separating of strands in DNA replication
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What is DNA polymerase?
Enzymes that catalyse the formation of phosphodiester bonds between adjacent nucleotides in DNA replication
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What is DNA relication?
The semi-conservative process of the production of identical copies of DNA molecules
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What is the double circulatory system?
A circulatory system where the blood travels twice through the heart for each complete circulation of the body. 1st circulation blood pumped to the lungs. 2nd circulation oxygenated blood pumped to the brain and body to supply cells with oxygen.
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What is a ectopic heartbeat?
Extra heartbeats that are out of the normal rythm
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What is elastic recoil?
The ability to return to original shape and size following stretching. Particularly of the alveoli of the lungs and the arteries
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What is a electrocardiogram?
A technique for measuring tiny changes in the electrical conductivity of the skin that results from the electrical activity of the heart. This produces a trace which can be used to analyse the health of the haert
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What is electron microscopy?
Microscopy using a microscope that employs a beam of electrons to illuminate specimens. As electrons have a much smaller wavelength than light they produce images with higher resolutions than light microscopes
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What is a emulsion test?
Laboratory tests for lipids using ethanol; a white emulsion indicates the presence of a lipid
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What are endocytosis?
The bulk transport of materials into cells via invagination of the cell surface membrane forming a vesicle
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What is endosymbiosis?
The widely-accepted theoretical process by which eukaryotic cells evolved from prokaryotic cells
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What is the end-product inhibition?
The product of a reaction inhibits the enzyme required for the reaction
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What is a enzyme-product complex?
Complex formed as a result of an enzyme-catalysed reaction, when a substrate is converted to a product or products while bound to an activ site of an enzyme
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What are enzymes?
Biological catalysts that interact with substrate molecules to facilitate chemical reaction. Usually globular proteins
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What is an enzyme-subrate complex?
Complex formed when a substrate is bound to the active site of an enzyme
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What is an epidemic?
When a communicable disease spreads rapidly to a lot of people at a local or national level
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What are eukaryotes?
Multicellular eukaryotic organisms like animals, plants and fungi and single celled protoctista
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What are eukaryotic cells?
Cells with a nucleus and other membrane bound organelles
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What is a ex situ conservation?
Conservation methods out of the natural habitat
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What is an exchange surface?
Surfaces over which materials are exchanged from one are to another
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What are exocytosis?
The bulk transport of materials out of cells. Vesicles containing the materials fuse with cell-surface membrane and the contents are released outside the cell
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What is an exoskeleton?
An external skeleton of some organisms, e.g.insects
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What is the expiratory reserve volume?
The extra amount of air that can be forced out of the lungs over and above the normal exhalation, (tidal volume)
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What is facilitated diffusion?
Diffusion across a plasma membrane through protein channels
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What is fatty acid?
Long chain carboxylic acids used in the formation of triglycerides
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What are fibrous proteins?
Long, insoluble, structural proteins
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What is a fluid mosaic model?
Model of the structure of a cell membrane in which phospholipids within the phospholipid bilayer are free to move and proteins of various shapes and sizes are embedded in various positions
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What is a fossil?
The remains of impressions of a prehistoric plant or animal preserved in rock
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What is a founder effect?
When a few individuals of a species colonise in a new area, their offspring initially experience a loss of genetic variation, and rare alleles can become much more common in the population
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What is fungi?
Biological kingdom containing yeasts, moulds and mushrooms
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What are gametes?
Haploid sex cells produced by meiosis in organisms that reproduce sexually
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What is the gaseous exchange system?
The complex systems in which the respiratory gases oxygen and carbon dioxide are exchanged in organisms
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What is a gene?
A section of DNA that contains the complete sequence of bases (codons) to code for a protein
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What is gene flow?
When alleles are transferred from one population to another by interbreeding
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What is a genetic bottleneck?
When large numbers of a population die prior to reproducing, leading to reduced genetic biodiversity within the population
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What is a genetic code?
The sequence of bases in DNA are the 'instructions' for the sequence of amino acids in the production of protein
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What is genetic variation?
A variety of different combinations of different alleles in a population
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What are gills?
The gaseous exchange organs of fish, comprised of gill plates, gill filaments and gill lamellae
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What are globular proteins?
Spherical, water-soluble proteins
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What is glucose?
A monosaccharide wih the chemical formula C6H12O6. One of the main products of photosynthesis in plants
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What is glycerol?
Alcohol found in triglycerides
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What is glycogen?
A branched polysaccharide formed from alpha glucose molecules. A chemical energy store in animals
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What are glycolipids?
Cell-surface membrane lipids with attached carbohydrate molecules of varying lengths and shapes
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What are glycoproteins?
Extrinsic membrane proteins with attached carbohydrate molecules of varying lenghts and shapes
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What is a glycosidic bond?
A covalent bond between 2 monosaccharides
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What are goblet cells?
Differentiated cells specialised to secrete mucas
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What is the Golgi apparatus?
Organelle in most eukaryotic cells formed from an interconnected network of flattened, membrane-enclosed sacs, or cisternae. Play a role in modifying and packaging proteins into vesicles
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What is Gran negative bacteria?
Bacteria with cell walls that stain red with Gram stain
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What is Gran positive bacteria?
Bacteria with cell walls that stain purple-blue with Gram stain
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What is granum? (plural grana)
A structure inside chloroplasts composed of a stack of several thylakoids. Contains chlorophyll pigments, where light reactions occur during photosynthesis
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What are guard cells?
Cells that can open and close the stomatal pores, controlling gaseous exchange and water loss in plants
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What is habitat biodiversity?
The number of different habitats found within an area
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What is haemoglobin?
The red, oxygen-carrying pigment of red blood cells
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What is haemoglobinic acid?
The compound formed when haemoglobin accepts free hydrogen ions in its role as a buffer in the blood
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What is haemolymph?
The transport medium or 'blood' in insects
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What does haploid mean?
Half the normal chromosome number; one chromosome of each type
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What is heterotrophic?
Organisms that acquire nutrients by the ingestion of other organisms
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What is a hexose monosaccharide?
A monosaccharide composed of 6 carbon
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What are histamines?
Chemicals produced by mast cells in damaged tissue that make blood vessles dilate (causing redness and heat) and the blood vessel walls leaky (causing swelling and pain)
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What are histones?
Proteins that form a complex with DNA called chromatin
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What are homologous chromosomes?
Matching pair of chromosomes, one inherited from each parent
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What is a homologous structure?
A structure which appears superficially different but has the same underlying structure
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What doe hydrophilic mean?
The physical property of a molecule that is attracted to water
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What does hydrophobic mean?
The physical property of a molecule that is repelled by water
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What are hydrophytes?
Plants with adaptations that enable them to survive in very wet habitats or submerged or at the surface of the water
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What is hydrostatic pressure?
The pressure created by water in an enclosed system
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What is an immune response?
A biological response that protects the body by recognising and responding to antigens and by destroying substances carrying non-self antigens
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What are immuneoglobulins?
Y-shaped glycoproteins that form antibodies
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What is in situ consrvation?
Conservation methods within the natural habitat
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What is independent assortment?
The arrangement of each homologous chromosome pair (bivalent) in metaphase 1 and metaphase 2 of meiosis is independent of each other and results in genetic variation
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What is the induced-fit hypothesis?
Modified lock and key explanation for enzyme action; the active site of the enzyme is modified in shape by binding to the substrate
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What is inflammation?
Biological response of vascular tissues to pathogens, damaged cells, or irritants, resulting in pain, heat, redness and swelling
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What is an inhibitor?
A factor that prevents or reduces the rate of an enzyme-catalysed reaction
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What is inspiratory reserve volume?
The maximum volume of air that can be breathed in over and above normal inhalation (tidal volume)
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What is insulin?
A globular protein hormone involved in the regulation of blood glucose concentration
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What are intercostal muscles?
The muscles between the ribs that pull the ribs upwards during inhalation (internal intercostal muscles) an downwards during forced exhalation (external intercostal muscles)
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What is interleukins?
A type of cytokine produced by T helper cells
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What is interphase?
Growth period of the cell cycle, between cell divisions (mitotic phase). Consists of stages G1, S and G2
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What is interspecific variation?
The differences between organisms of different species
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What is intraspecific variation?
The differences between organisms of the same species
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What is the iodine test?
A chemical test for the presence of starch using a potassium iodine solution. A colour change to purple/black indicates a positive result
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What is ion?
An atom or molecule with an overall electric charge because the total number of electrons is not equal to the total number of protons
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What is an ionic bond?
A chemical bond that involves the donating of an electron from one atom to another, forming positive and negative ions held together by the attraction of the opposite charge
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What are keystone species?
Species which are essential for maintaining biodiversity - they have a disproportionately large effect on their environment relative to their abundance
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What is a kingdom?
The second biggest and broadest taxonomic group
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What is lactose?
A disaccharide made up of a galactose and glucose monosaccharide
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What is a laser scanning confocal microscope?
A microscope that employs a beam of fluorescence and a pin-hole aperture to produce an image with a high reolution
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What is a light microscope?
An instrument that uses viable light and glass lenses to enable the user to see objects magnified many times
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What is a line transect?
A line is marked along the ground and samples are taken at specified points
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What are lipids?
Non-polar macromolecules containing the elements carbon,hydrogen and oxygen. Commonly known as fats (solid at room temperature) and oils (liquid at room temperature)
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What is a lung surfactant?
Chemical mixture containing phospholipids and both hydrophilic and hydrophobic proteins, which coats the surfaces of the alveoli and prevents them collapsing after every breath
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What is a lymph?
Modified tissue fluid that is collected in the lymph system
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What are lymphocytes?
White blood cells that make up the specific immune system
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What are lysosomes?
Specialised vesicles containing hydrolytic enzymes for the beadown of waste materials within a cell
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What are Macromolecules?
Large complex molecules with a large molecular weight
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What is maltose?
2 Glucose molecules linked by a 1,4 glycosidic bond
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What is a mass transport system?
A transport system where substances are transported in a mass of fluid
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What is meiosis?
Form a cell division where the nucleus divides twice (meiosis 1 and meiosis 2) resulting in a halving of the chromosome number and producing 4 haploid cells from 1 diploid cell
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What is a membrane?
A selectively-permeable barrier surrounding all cells and forming compartments within eukaryotic cels
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What are membrane proteins?
Protein components of cell-surface membranes
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What is meristematic tissue? (meristems)
Tissue found at regions of growth in plants. Contains stem cells
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What is messenger (m) RNA?
Short strand of RNA produced by transcription from the DNA template strand. It has a base sequence complementary to the DNA from which it is transcribed, except it has uracil (U) in a place of thymine (T)
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What is metaphase?
Second stage of mitosis when chromosomes line up at the metaphase plate
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What is mitrochondrial DNA?
DNA present within the matrix of mitrochondria
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What is mitosis?
Nuclear division stage in the mitotic phase of the cell cycle
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What is the mitotic phase?
Period of cell division of the cell cycle. Consists of the stages mitosis and cytokinesis
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What is monoculture?
The cultivation of a single crop in a given area
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What are monomers?
Individual molecules that make up a polymer
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What are monosaccharides?
A single sugar molecule
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What is MRSA? (methicillin-resistant Staphylococcus aureus)
A mutated strain of the bacterium staphylococcus aureus that is resistant to the antibiotic, methicillin
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What is mucous membranes?
Membranous linings of body tracts that secrete a sticky mucus
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What is multipotent?
A stem cell that can only differentiate into a range of cell types within a certain type of tissue
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What is a mutation?
A change in the genetic material which may affect the phenotype of the organism
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What is a myogenic?
A muscle which has its own intrinsic rhythm
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What is natural active immunity?
Immunity which results from the response of the body to the invasion of a pathogen
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What is natural passive immunity?
The immunity given to an infant mammal by the mother through the placenta and the colostrum
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What is natural selection?
The process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes
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What is a non-competitive inhibitor?
An inhibitor that binds to an enzyme at an allosteric site
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What is a non-random sampling?
An alternative sampling method to random sampling, where the sample is not chosen at random. It can be opportunistic, stratified or systematic
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What is a normal distribution curve?
The bell-shaped curve that results from plotting continuous variation data on a graph
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What are nucleic acids?
Large polymers formed from nucleotides. Contain the elements Carbon,Hydrogen, Nitrogen, Phosphorus and Oxygen
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What are nucleotides?
The monomers used to form nucleic acids. Made up of a pentose monosaccharide, a phosphate group and a nitrogen base
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What is oncotic pressure?
The tendency of water to move into the blood by osmosis as a result of plasma proteins
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What is a open circulatory system?
A circulatory system with a heart but a few vessels to contain the transport medium
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What is the operculum?
The bony flap covering the gills of bony fish. Part of the mechanism that maintains a constant flow of water over the gas exchange surface
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What is opportunistic sampling?
Sampling using the organisms that are conveniently available. The weakest form of sampling as it may not be representative pf the population
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What are opsonins?
Chemicals that bind to pathogens and tag them so they are recognised more easily by phagocytes, e.g. antibodies
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What is an organelle?
Membrane-bound compartments with varying functions inside eukaryotic cells
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What is osmosis?
Diffusion of water through a partially permeable membrane down a water potential gradient. A passive process
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What is a oxygen dissociation curve?
A graph showing the relationship between oxygen and haemoglobin at different partial pressures of oxygen
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What is oxygenated blood?
Blood that has passed through the gas exchange organs (e.g.lungs) and is high in oxygen
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What is a pandemic?
When a communicable disease spreads rapidly to a lot of people across a number of countries
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What is partially permeable?
Membranes that allow some substances to cross but not others
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What is passive transport?
Transport that does not require energy and does not use cellular respiration
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What are pathogens?
Microorganisms that cause disease
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What is penecillin?
The first widely used, safe antibiotic, derived from a mould
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What is pentose monosaccharide?
A monosaccharide composed of 5 carbons
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What is a peptide bond?
Bond formed between 2 amino acids
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What are peptides?
Chains of 2 or more amino acid molecules
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What are phagocytosis?
Process by which white blood cells called phagocytes recognise non-self cells, engulf them and digest them within a vesicle called phagolysome
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What is a phagosome?
The vesicle in which a pathogen or damaged cell is engulfed by a phagocyte
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What is a phloem?
Plant transport tissue that carries the products of photosynthesis (assimilates) to all cells of the plant
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What is a phosphodiester bond?
Covalent bonds formed between the phosphate group of one nucleotide and the y=hydroxyl (OH) group of another
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What is a phospholipid bilayer?
Arrangement of phospholipids found in cell membranes; the hydrophilic phosphate heads form both the inner and outer surface of a membrane, sandwiching the fatty acid tails to form a hydrophobic core
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What are phospholipids?
Modified triglycerides, where one fatty acid has been replaced with a phosphate group
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What is a phylogeny?
The evolutionary relationships between organisms
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What are pinocytosis?
Endocytosis of liquid materials
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What is the plasma?
The main component of blood, a yellow fluid containing many dissolved substances and carrying the blood cells
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What are plasma cells?
B lymphocytes that produce about 2000 antibodies to a particular antigen every second and release them into the circulation
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What is a plasma membrane?
All the membranes of cells, which have the same basic structure described by the fluid-mosaic model
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What is pluripotent?
A stem cell that can differentiate into any type of cell, but not form a whole organism
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What are polymers?
Long, chain molecules compose of linked (bonded) multiple individual molecules (monomers) in a repeating pattern
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What is a polypeptide?
Chains of 3 or more amino acids
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What are polysaccharides?
A polymer made up of many sugar monomers (monosaccharides)
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What is a primary immune response?
The relatively slow production of a small number of the correct antibodies the 1st time a pathogen is encountered
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What are prokaryotes?
Single-celled prokaryotic organisms from the kingdom Prokaryotae
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What are prokaryotic cells?
Cells with no membrane-bound nucleus or organelles
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What is prophase?
1st Stage of mitosis when chromatin condenses to form visible chromosomes and the nuclear envelope breaks down
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What is a prosthetic group?
Non-protein component of a conjugated protein
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What is protease?
Enzymes that catalyse the breakdown of proteins and peptides into amino acids
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What are proteins?
1 or more polypeptides arranged as a complex macromolecule
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What is a protista?
Biological kingdom containing unicellular eukaryotes
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What are purines?
Double-ringed, nitrogenous bases that form part of a nucleotide
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What are Purkyne fibres?
Tissue that conducts the wave of excitation to the apex of the heart
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What are pyrimidines?
Single-ringed, nitrogenous bases that form part of a nucleotides
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What is a quaternary structure?
The association of 2 or more protein subunits
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What is random sampling?
Sampling where each individual in the population has an equal likelihood of selection
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What are receptors?
Extrinsic glycoproteins that bind chemical signals, triggering a response by the cell
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What are recombinant chromatids?
Chromatids with a combination of DNA from both homologous chromosomes, formed by crossing over and chiasmata in meiosis
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What are reducing sugars?
Saccharides (sugars) that donate electrons resulting in the reduction (gain of electons) of another molecule
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What is reduction division?
Cell division resulting in the production of haploid cells from a diploid cell; meiosis
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What is residual volume?
The volume of air that is left in the lungs after forced exhalation. It cannot be measured directly
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What is resolution?
The shortest distance between 2 objects that are still seen as separate objects
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What is an R-groups?
Variable groups on amino acids
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What is ribonucleic acid? (RNA)
Molecules involved in the copying and transfer of genetic information from DNA. Polynucleotides consisting of a ribose sugar and 1 of 4 bases; uracil (U), cytosine (C), adenine (A), and guanine (G)
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What are ribose?
The pentose monosaccharide present in RNA molecules
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What is ribosomal (r) RNA?
Form of RNA that makes up the ribose
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What is RNA polymerase?
Enzyme that catalyses the formation of phosphodiester bonds between adjacent RNA nucleotides
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What is a root hair cell?
Cells found just behind the growing tip of a plant root that have long hair-like extensions that greatly increase the surface area available for the absorption of water and minerals from the soil
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What is root pressure?
The active pumping of minerals into the xylem by root hair cells that produce a movement of water into the xlem by osmosis
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What are saprophytic?
Organisms that acquire nutrients by absorption - mainly of decaying material
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What is scanning electron microscopy?
An electron microscope in which a beam of electrons is sent across the surface of a specimen an the reflected electrons are focused to produce a 3-D image of the specimen surface
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What is a secondary immune response?
The relatively fast production of very large quantities of the correct pathogen is encountered as a result of immunological memory - the second stage of a specific immune response
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What is a seed bank?
A store of genetic material from plants in the form of seeds
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What is selection pressure?
Factors that affect an organisms chance of survival or reproductive success
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What is selective toxicity?
The ability to interfere with the metabolism of a pathogen without affecting the cells host
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What does selectively permeable mean?
Plasma membrane with protein channels that allow specific substances to cross only
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What is selectively-conservative replication?
DNA replication results in 1 old strand and 1 new strand present in each daughter cell DNA molecule
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What is a sense strand?
The strand of DNA that runs 5' to 3' and contains the genetic code for a protein
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What are sieve plates?
Areas between the cells of the phloem where the walls become perforated giving many gaps and a sieve-like appearance that allows the phloem contents to flow through
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What are sieve tube elements?
The main cells of the phloem that have a greatly reduced living content and sieve plates between cells
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What is Simpson's Index of Diversity?
A measure of biodiversity that takes into account both species richness and species evenness
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What is the single circulatory system?
A circulatory system where the blood flows through the heart and is pumped out to travel all over the body before returning to the heart
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What are sinks? (in plants)
Regions of a plant that require assimilates to supply their metabolic needs, e.g. roots, fruits
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What is the sino-atrial node? (NAN)
Region of the heart that initiates a wave of excitation that triggers the contraction of the heart
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What is the smooth endoplasmic reticulum?
Endoplasmic reticulum lacking ribosomes; the site of lipid and carbohydrate synthesis, and storage
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What are sources? (in plants)
Regions of a plant that produce assimilates (e.g. glucose) by photosynthesis or from storage materials, e.g. leaves, storage organs
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What does specialised mean?
Having particular structure to serve a specific structure
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What is a species?
The smallest and most specific taxonomic group
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What is specific immunity?
Also known as active immunity or acquired immunity - the immune system 'remembers' an antigen after an initial response leading to an enhanced response to subsequent encounters
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What are spiracles?
Small openings along the thorax and abdomen of an insect that opens and closes to control the amount of air moving in and out of the gas exchange system and the level of water loss from the exchange surfaces
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What is a stage graticule?
A slide with a scale in micrometres etched into it. Used to measure the size of a sample under a light microscope
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What are stains? (staining)
Dyes used in microscopy sample preparation to increase contrast or identify specific components
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What is starch?
A polysaccharide formed from alpha glucose molecules either joined to form amylose or amylopectin
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What are stem cells?
Undifferentiated cells with the potential to differentiate into any of the specialised cell types of the organism
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What is a stomata?
Pores in the surface of a leaf or stem that may be opened and closed by guard cells
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What is stratified sampling?
Samplings where populations are divided into sub-groups (strata) based on a particular characteristic. A random sample is taken from each of these strata proportional to its size
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What is a stroma?
Fluid interior in the chloroplasts
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What is the Student t test?
Statistical test used to compare the means of data values of 2 populations
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What is a substrate?
A substance used, or acted on, by another process or substance. For example a reactant in an enzyme-catalysed reaction
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What is succession?
The progressive replacement of 1 dominant type of species or community by another in an ecosystem, until a stable climax community is established
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What is sucrose?
A disaccharide made up of fructose and glucose monosaccharides
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What is sustainable development?
Economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs
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What is a symplast?
The continuous cytoplasm of living plant cells connected through the plasmodesmata
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What is a symplast route?
Phloem loading through the cytoplasm of the cells via the plasmodesmata by diffusion (passive)
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What is systamatic sampling?
Different areas of a habitat are identified and sampled separately. Often carried out using a line or belt transect
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What is systole?
The stages of the cardiac cycle in which the atria contract, followed by the ventricles, forcing blood out of the right side of the heart to the lungs and the left side of the heart to the body
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What are T helper cells?
T lymphocytes with CD4 receptors on their cell-surface membranes, which bind to antigens on antigen-presenting cells and produce interleukins, a type of cytokine
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What are T killer cells?
T lymphocytes that destroy pathogens carrying a specific antigen with perforin
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What are T lymphocytes?
Lymphocytes which mature in the thymus gland and that both stimulate the B lymphocytes and directly kill pathogens
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What are T memory cells?
T lymphocytes that live a long time and are part of the immunological memory
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What are T regulator cells?
T lymphocytes that suppress and control the immune system, stopping the response once a pathogen has been destroyed and preventing an autoimmune response
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What is tachycardia?
A fast heart rhythm of over 100 beats per minute at rest
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What is a taxonomic group?
The hierarchical groups of classification - domain, kingdom, phylum, class, order, family, genus and species
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What is telophase?
4th Stage in mitosis when chromosomes assemble at the poles and the nuclear envelope reforms
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What is a temperature coefficient? Q10
A measure of how much the rate of a reaction increases with a 10'C temperature increase
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What is a template strand?
The antisense strand of DNA that acts as template during transcription so that the complementary RNA strand formed carries the same code for a protein as the DNA sense strand
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What is a tertiary structure?
Further folding of the secondary structure of proteins involving interactions between R-groups
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What is tidal volume?
The volume of air which moves into and out of the lungs with each resting breath
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What is tissue?
A collection of differentiated cells that have a specialised function/functions in an organism
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What is tissue fluid?
The solution surrounding the cells of multicellular animals
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What are tonoplasts?
Membrane forming a vacuole in a plant cell
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What is total lung capacity?
The sum of the vital capacity and the residual volume
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What is a totipotent?
A stem cell that can be differentiated into any type of cell and form a whole organism
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What is the trachea?
The main airway, supported by incomplete rings of cartilage, which carries warm moist air down from the nasal cavity into the chest
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What is trachea fluid?
Fluid found at the ends of the tracheoles in insects that helps control the surface area available for gas exchange and water loss
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What is transcription?
The process of copying sections of DNA base sequence to produce smaller molecules of mRNA, which can be transported out of the nucleus via the nuclear pores to the site of protein synthesis
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What is transfer (t) RNA?
Form of RNA that carries an amino acid specific to its anticodon to the correct position along mRNA during translation
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What is translation?
The process by which the complementary code carried by mRNA is decoded by tRNA into a sequence of amino acids. This occurs at a ribosome
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What is translocation?
The movement of organic solutes around a plant in the phloem
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What is transmission electron microscopy? (TEM)
An electron microscope in which a beam of electrons is transmitted through a specimen and focused to produce an image
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What is transpiration?
The loss of water vapour from the stems and leaves of a plant as a result of evaporation from cell surfaces inside the leaf and diffusion down a concentration gradient out through the stomata
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What is a transpiration stream?
The movement of water through a plant from the roots until it is lost by evaporation from the leaves
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What is a transport system?
The system that transports required substances around the body of an organism
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What is a triglyceride?
A lipid composed of 1 glycerol molecule and 3 fatty acids
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What is a triplet code?
The genetic code is a sequence of 3 nucleic acid bases, called a codon. Each codon codes for 1 amino acids
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What is turgor?
The pressure exerted by the cell-surface membrane against the cell wall in a plant cell
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What is the ultrastructure?
The ultrastructure of the cell is those features which can be seen by using an electron microscope
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What is undifferentiated?
An unspecialised cell originating from mitosis or meiosis
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What is a vaccine?
A safe form of an antigen, which is injected into the bloodstream to provide artificial active immunity against a pathogen bearing the antigen
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What are vacuoles?
Membranous sacs used to transport materials in the cell
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What is vascular bundle?
The vascular system of herbaceous dicots, made up of xylem and phloem tissue
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What is the vascular system?
A system of transport vessels in animals or plants
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What is a vector?
A living or non-living factor that transmits a pathogen from one organism to another, e.g. malaria mosquito
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What is a Ventilation rate?
Is the total volume of air inhaled in 1 minute. Ventilation rate = tidal volume * breathing rate (per minute)
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What is vital capacity?
Volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath
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What is Vmax?
Maximum initial velocity or rate of an enzyme-catalysed reaction
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What is water potential?
Measure of the quantity of water compared to solutes, measured as the pressure created by the water molecules in kilopascals (kPa)
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What are xerophytes?
Plants with adaptations that enable them to survive in dry habitats where water is in short supply in the enviroment
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What is the xylem?
Plant transport tissue that carries water and minerals from the roots to the other parts of the plants as a result of physical forces
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What is a zygote?
The initial diploid cell formed when 2 gametes are joined by means of sexual reproduction. Earliest stage of embryonic development
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