Key Word Definitions

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  • Created by: MaMIlne
  • Created on: 09-11-17 15:41
Activation Energy
Energy required to bring about a reaction. The activation energy is lowered by the presence of enzymes
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Active Immunity
Resistence to disease resulying from the activities of an individuals own immune system whereby an antigen induces plasma cells to produce antibodies.
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Active Site
A group of amino acids that makes up the region of an enzyme into which the substrate fits in order to catalyse a reaction.
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Active Transport
movement of a substance from a region where it is in a low conentration to a region where it is in a high concentration. The process requires the expenditure of metabloic energy.
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Aerobic
Connected with the presence of free oxygen. Aerobic respiration requires free oxygen to release energy from glucose.
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Allele
One of a number of alternative forms of a gene. for example, the gene for the shape of a pea seed has two alleles: one for "round" and one for "wrinkled".
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Allergen
A normally harmless substance that causes the immune system to produce an immune response.
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Allergy
The response of the immune system to an allergen. Examples include hay fever and asthma.
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Antibiotic
A substance produced by living organisims that can destroyor inhibit the growth of microorganisims.
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Antibiotic Resisitance
The development in microorganisms of mechanisms that prevent antibiotics from killing them.
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Antibody
A protein produced by lymphocytes in response to the presence of the appropriate antigen.
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Anticodon
A sequence of three adjacent nucleotides on a molecule of transfer RNA that is complementary to a particular codon on a mesenger RNA molecule.
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Antigen
A molecule that triggers an immune response by lymphocytes.
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Antioxidant
Chemical which reduces or prevents oxidation. Often used as an additive to prolong the shelf-life of certain foods.
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Apoplastic Pathway
Route throught the cells walla and intercellular spaces of plants by which water and dissolved substances are transported.
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Artificial Selection
Breeding of organisims by human selection of parents/gametes in order to perpetuate certain characteristics and/or eliminate others.
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Asthma
A chronic illness in which there is resistence to air flow to the alveoli of the lungs as a result of the airways becoming inflamed due to an allergic response to an allergen.
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Atheroma
fatty deposits in the walls of arteries often associated with high cholesterol levels in the blood.
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ATP (adenosine triphosphate)
Nucleotide found in all livng organisims which is produced during respiration and is important in the transfer of energy.
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Autosomes
A chromosome which is not a sex chromosome.
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B Cell (B Lymphocyte)
Type of white blood cell that is produced and matures within the bone marrow. B lymphocytes produce antibodies as part of their role in immunity.
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Benedicts Test
A simple biochemical reaction to detect the presence of reducing sugars.
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Biodiversity
The range and variety of genes, species and habitats within a particular region.
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Biomass
The total mass of living material, normally measured in a specific area over a given period of time.
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Biuret Test
A simple biochemical reaction to detect the presence of a protein.
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Body Mass Index (BMI)
A persons body mass in kilograms divided by the square of their height in meters.
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Cancer
A disease, resulting from the cells that break away from the original tumour to form secondary tumours elsewhere in the body.
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Carcinogen
A chemical, a form of radiation, or other agent that causes cancer.
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Cardiac Cycle
A continuous series of events which make up a single heart beat.
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Cardiac Output
The total volume of bloo that the heart can pump each minute. It is calculated as the volume of blood pumped at each beat (stroke volume) multiplied by the number of heart beats per minute (heart rate).
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Carrier Molecule (carrier protein)
A protein on the surface of a cell that helps to transport mleules and ions across plasma membranes.
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Casparian *****
A distinctive band of suberin around the endodermal cells.
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Centrifugation
Process of seperating out particles of differnt sizes and densities by spinning them at high speed in a centrifuge.
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Choleterol
Lipid that is an important component of cell-surface membranes. Excess in the blood can lead to atheroma.
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Chromatid
one of the two strands of a chromosome that are joined together by a single centromere prior to cell division.
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Chromatin
The material that makes up chromosomes. It cosists of DNA and the protein histone.
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Chromosome
A thread- like structure made of protein and DNA by which herediatry information is physically passed from one generation to the next.
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Clone
A group of genetically identical cells or organisims frormed from a single parent as the result of asexual reproduction or by artificial means.
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Codon
A sequence of three adjacent nucleotides in mRNA that codes for one amino acid.
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Cohesion
Attraction between molecules of the same type. It is important in the movement of water up by a plant.
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Collagen
Fibrous protein that is the main constituent of connective tissues such as tendons, cartilage and bone.
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Community
All the living organisims present in an ecosystem at a given time.
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Complementary DNA
DNA that is made from messenger RNA in a process that is the reverse of normal transcription.
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Condensation
Chemical process in which two molecules combing to form a more complex one with the elimination of a simple substance, usually water. Many biological polymers, such as polysaccharides and polypeptides, are formed by condensation.
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Continuous Variation
Variation in which organisims do not fall into distinct catergories but show gradations from one extreme to the other.
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Coronary Arteries
Arteries that supply blood to the cardiac muscle of the heart.
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Coronary Heart Disease (CHD)
Any condition, for example, atheroma and thrombosis, affecting the coronary arteries that supply heart muscle.
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Correlation
When a change in one viariable is reflected by a change in the second variable.
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Co-Transport
The transport of one substance coupled with the transport of another substance across a plasma membrane in the same direction through te same protein carrier.
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Countercurrent System
A mechanism by which the efficiency of exchange between two substances is increased by having the flowing in opposite directions.
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Covalent Bond
Type of chemical bond in which two atons share a pair of electrons, one from each atom.
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Crossing Over
The procss wherby a chromatid breaks during meiosis and the rejoins to the chromatid of its homologous so that their alleles are exchanged.
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Denaturation
Permanent changes due to the unravelling of the three-dimensional structure of a protein as a result of factors such as changes in temperature or pH.
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Diastole
The stage in the cardiac cycle when the heart muscle relaxes.
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Differentiation
The process by which cells become specialised for differentation funtions.
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Diffusion
The movement of molecules or ions from a region where they are in high concentration to one where their concentration is lower.
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Diploid
AQ term applied to cells in which the nucleus contains two sets of chromosomes.
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Dipolar
Having a pair of equal and opposite eletrical charges.
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Ecological Niche
Discribes how an organism fits into its environment. It describes what a species is like, where it occurs, how it behaves, its interacions with another species and how it rsponds to its environment.
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Ecosystem
All the living and non-living components of a particular area.
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Electron
Negatively charged subatomic particle that orbits the postively charged nucleus of all atoms.
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Emphysema
A disease in which the walls of the alveoli break down, reducing the surface area for gaseous exchange, thereby causing breathlessness in the patient.
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Endocytosis
The inward transport of large molecules through the cell-surface membrane.
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Enzyme
A protein or RNA that acts as a catalyst and so alters the sped of a biohemical reaction.
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Epidemiology
The study of the spread of disease and the factors that affect this spread.
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Eukaryotic Cell
A cell that has a membrane-bound nucleus and chromosomes. The cell also possesses a variety of other membranous organelles, shuch as mitochondria and endoplasmic reticulum.
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Exocytosis
The outward bulk transport of materials through the cell-surface membrane.
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Facilitated Diffusion
Diffusion involving the presence of protein carrier molecules to allow the passive movement of substances across plasma membranes.
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Gamete
Reproductive (sex) cell that fuses with another gamete during fertilisation.
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Gene
Section of DNA on a chromosome coding for one or more polypeptides.
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Gene Pool
The total nukmber of alleles in a particular population at a specific time.
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Glycolysis
Firsyt part of cellular respiration in which glucose is broken down anerobically in the cytoplasm to two molecules of pyruvate.
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Habitat
The place where an organisms ormally lives and which is characterised by physical conditions and the types of other organisms present.
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Haemoglobin
Globular protein in the blood that readily combines with oxygen to transport it around the body. It comprises four polypeptide chains around an iron-containing haem group.
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Haploid
term referring to cells that contain only a single copy of each chromosome e.g. the sex cells
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Homologous Chromosome
A pair of chromosomes, one maternal and one paternal, that have the same gene loci and therfore determine the same features. They are not necessarily identical, however, as individual alleles of the same gene may vary.
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Human Genome
The totality of the DNA sequences on the chromosomes of a single human cell.
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Hydrogen Bond
Chemical bond formed between the positive charge on another atom of an adjacent molecule.
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Hydrolysis
The breaking down of a large molecules into smaller one by the addition of water molecules.
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Immunity
The means by which the body protcets itself from infection.
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Intercropping
The practise of growing two or more crops in close proximity usually to produce a greater yeild on a peice of land.
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Interspecific Variation
Differnces between organisms of differnt species.
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Intracific Variation
Differnces between organisms of the same species.
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Ion
An atom or group of atoms that has lost or gained one ore more electrons. Ions therfore have either a positive or negative charge.
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Ion Channel
A passage across a cell-surface membrane made up of a protein that spans the membrane and opens and closes to allow ions to pass in and out of the cell.
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Isotope
Variations of a chemical element that have the same number of protons and electrons but different numbers of neutrons.
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Kinetic Energy
Energy that an object possesses due to its motion.
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Latent Heat of Vaporisation
Heat taken in by a liquid in order to transform it into a vapour.
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Locus
The position of a gene on a chromosome/DNA molecule.
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Lumen
The hollow cavity inside tubular structure such as the gut or a xylem vessel.
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Lymph
A slightly milky fluid found in lymoh vessels and made up of tissue fluid, fats and lymphocytes.
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Lmphocytes
Types of white blood cell resposible for the immune response. They become activated in the presence of antigens. There are two types: B lymphocytes and T lymphocytes.
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Meiosis
The type of nuclear division in which the number of chromosomes is halved.
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Mesophyll
Tissue found between the two layers of epidermis in plant leaf comprising an upper layer of palisadecells and a lower layer of spongy cells.
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Metabolism
All the chemical processes that take place in all living organisms.
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Microvilli
Tiny finger-like projections from the cell-surface membrane of some animal cells.
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Middle Lamella
Layer made up of pectins and other substances found between the walls of adjacent plant cells.
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Mitosis
The type of nuclear division in which the daughter cells have the same number of chromosomes as the parent cell.
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Monocolonal Antibody
An antibody produced by a single clone of cells.
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Monomer
One of many small molecules that combine to form a larger one known as a plolymer.
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Mono-unsaturated Fatty Acid
Fatty acid that possesses a carbon chain with a single double bond.
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Mutation
A sudden change in the amount or the arrangement of the genetic material in the cell.
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Myocardial Infraction
Otherwise known as a hear attack, results from the interruption of the blood supply to the heart muscle, causing damage to an area of the heartwith cosequent distruption to its function.
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Nitrogen Fixation
The incorporation of atmospheric nitrogen gas into organic nitrogen-containing compounds.
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Normal Distribution
A bell-shaped curve produced when a certain distribution is plotted on a graph.
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Nucleotides
Complex chemicals made up of an organic base, a sugar and a phosphate. They are the basic units of which the nucleic acids DNA and RNA are made.
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Oral RehydrationSolution (ORS)
Means of treating dehydration involving giving, by mouth, a balanced solution of salts and glucose that stimulates the gut to reabsorb water.
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Osmosis
The passage of water from a region of high water potential to a region where its water potential is lower, through a partially permeable membrane.
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Oxidation
Chemical reaction invlolving the loss of electrons.
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Palaside Cells
LOng, narrow cells, packed with chloroplasts, that are found in the upper region of a leaf and which carry out photosynthesis.
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Passive Immunity
Resisitence to disease that is acquired from the introduction of antibodies from another individual, rather that an individual's own immune system, e.g. across the placenta or in the mothers milk. It is usually short-lived.
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Pathogen
Any microorganims that causes disease.
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Pentose Sugar
A sugar that possesses five carbon atoms. E.g. ribose and deoxyribose.
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Peptide Bond
The chemical bond formed between two amino acids during condensation.
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Phagocytosis
Mechanism by which cells ingulf particles to form a vesicle or a vacuole.
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Phospholipid
Triglycerides in which one of the three fatty acid molecules is replaced by a phosphate molecule. Phospholipids are important in the structure and functioning of plasma membranes.
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Photomicrograph
Photograph of an image produced by a microscope.
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Plasmid
A small circular piece of Dna found in bacterial cells.
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Plasmodesmata
Fine stands of cytoplasm that extend through pores in adjacent plant cell walls and connect the cytoplasm of one cell with another.
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Plasmolysis
The shrinkage of cytoplasm away from the cell wall that occurs as a plant cell loses water by osmosis.
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Polymer
Large molecule made up of repeating smaller molecules (monomers)
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Polymerases
Group of enzymes that catalyse the formation of long-chain molecules (polymers) from similar basic units (monomers).
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Polyunsaturated Fatty Acid (PUFA)
Fatty acud that possesses carbon chains with many double bonds.
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Primary Structure of a Protein
The sequence of amino acids that makes up polypeptides of a protein.
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Prokaryotic Cell
A cell of an organism belonging to the kingdom Prokaryotae that is characterised be lacking a nucleus and membrans-bound organelles. E.g. bacteria
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Protoplast
The living portion of a plant cell, that is, the nucleus and cytoplasm along with the oranelles it contains.
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Quaternary Structure of a Protein
A number of polypeptide chains linked together, and sometimes assoiciated with a non-protein groups, to form a protein.
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Reduction
Chemical process involving the gain of electrons.
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Saturated Fatty Acid
A fatty acid in which ther are no double bonds between the carbon atoms.
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Secondary Structure of a Protein
The way in which the chain of amino acids the polypeptides of a protein is folded.
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Semi-conservative Replication
The means by which DNA makes exact copies of itself by unwinding the double helix so that each chain acts as a template for the next. The new copies therefore possess one original and one new starnd of DNA.
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Serum
Clear liquid that is left after blood has clotted and the clot has been removed. It is therefore blood plasma without the clotting factors.
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Sinoatrial Node (SAN)
An area of the heart muscle in the right atrium that controls and coordinates the contraction of the heart. Also known as a pacemaker.
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Species
A group of similar organisms that can breed together that can breed together to produce fertile offspring.
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Stoma (plural stomata)
apore, mostly found in the lower epidermis of a leaf, though which gases diffuse in and out of the leaf.
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Stroke Volume
The volume of blood pumped at each ventricular contraction of the heart.
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Substrate
A substance that is acted on or used by another substance or process. In which microbiology, the nutrient medium sed to grow microorganisms.
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Supernatant Liquid
The liquid portion of a mixture left at the top of the tube when suspended particles have been seperated out at the bottom during centrifugation.
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Symplastic Pathway
Route through the cytoplasm and plasmodesmata of plant cells by which water substances are transported.
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Systole
The stage in the cardiac cycle in which the heart muscle contracts. It occurs in two stages: atrial systole when the atria contract and the ventricular systole when the ventricles contract.
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Tertiary Structure of a Protein
The foldinbg od a whole peptide chain in a precise way, as determined by the amino acids which it is composed.
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Thrombosis
Formation of a blood clot within a blood vessel that may lead to a blockage.
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Tidal Volume
The volume of air breathed in and out during a single breath when at rest.
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Tissue
A group of similar cells organised into a structual unit that serves a particular function.
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Tissue Fluid
Fluid that surrounds the cells of the body. Its composition is similar to that of blood plasma except that it lacks proteins. It supplies nutrients to the cells and removes waste products.
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T Cell (T lumphocyte)
Type of white blood cell that is produced in the bone marrow but matures in the thymus gland. T lymphocytes coordinate the immune response and kill infected cells.
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Transpiration
Evaporation of water from a plant.
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Triglyceride
An individual lipid molecule made up of a glycerol molecule and three fatty acids.
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Tumour
A swelling in an organism that is made up of cells that continue to divide in an abnormal way.
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Turgid
A plant cell that contains the maximum volume of water it can. Additional entry of water is prevented by the cell wall stopping further expansion of the cell.
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Ultrafiltration
Filtraion assisted by blood pressur, e.g. in the formation of tissue fluid.
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Unsaturated Fatty Acid
A fatty acid in which there are one or more double bonds between the carbon atoms.
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Vaccination
The introduction of a vaccine containing appropriate disease antigens into thebody, by infection or mouth, in order to induce artificial immunity.
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Water Potential
The pressure created by water molecules. It is the measure of the extent to which a solution gives out water molecules present, the higher (less negative) the water potential. Pure water has a water potential of zero.
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Xerophyte
A plant adapted to living in dry conditions.
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Xylem Vessels
Dead, hollow, elongated tubes, with lignified side wall and no end walls, that trasport water in most plants.
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Other cards in this set

Card 2

Front

Active Immunity

Back

Resistence to disease resulying from the activities of an individuals own immune system whereby an antigen induces plasma cells to produce antibodies.

Card 3

Front

Active Site

Back

Preview of the front of card 3

Card 4

Front

Active Transport

Back

Preview of the front of card 4

Card 5

Front

Aerobic

Back

Preview of the front of card 5
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