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339 Cards in this Set
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Cells in the islets of Langerhans that release glucagon in response to low blood glucose levels. |
Alpha cells
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A neurotransmitter (transmitter substance) found in cholinergic synapses.
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Acetylcholine
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An enzyme in the synaptic cleft that breaks down the transmitter substance acetylcholine.
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Acetylcholinesterase
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A protein found in muscle cells. It is the main component of the thin filaments.
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Actin
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A brief reversal of the resting potential across the cell surface membrane of a neurone. All action potentials have a value of +40_mV.
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Action potential
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The enzyme found inside cells, associated with hormone receptors, that converts ATP to cAMP.
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Adenyl cyclase
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Of a nerve meaning Incoming or leading towards.
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Afferent
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An alternative version of a gene.
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Allele
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Refers to the fact that a neurone either conducts an action potential or it does not.
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All or nothing
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Transplantation of organs between individuals of the same species, for example transplantation of a human heart into another human.
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Allotransplantation
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The making of multiple copies of the same short section of DNA. The process of PCR is used in automatic amplification of DNA sections.
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Amplification (DNA) |
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Drugs that mimic the action of steroid hormones and increase muscle growth.
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Anabolic steroids
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Type of metabolism: biochemical reactions that synthesise large molecules from smaller molecules. This requires energy/ATP.
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Anabolism
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Working against each other in a pair.
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Antagonistic
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The term used to describe hydrogen-bond formation between complementary base pairs when sections of single-stranded DNA or RNA join together. Occurs when complementary sticky ends join and where DNA probes attach to a complementary DNA section.
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Annealing
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The hormone made in the hypothalamus and released from the pituitary gland that acts on the collecting ducts in the kidneys to increase the reabsorption of water into the blood.
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Antidiuretic hormone (ADH)
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The growing apical bud at the tip of the shoot inhibits growth of lateral buds further down the shoot.
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Apical dominance
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Programmed cell death. An orderly process by which cells die after they have undergone the maximum number of divisions.
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Apoptosis
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The limb of the loop of Henle that carries fluid from the medulla towards the cortex of the kidney.
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Ascending limb
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Literally means without contamination. In biotechnology, this refers to lack of contamination by foreign, unwanted microorganisms.
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Asepsis
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Any techniques/manipulations of equipment or materials that are designed to prevent contamination by foreign and unwanted microorganisms.
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Aseptic techniques
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A region of the cerebral cortex where the information in the form of impulses from sensory areas is made sense of by comparison with previous experience.
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Association area
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Molecule found in all living cells and involved in energy transfer. When it is hydrolysed energy is released. Made up of adenine, a ribose sugar and 3 phosphate groups. |
ATP
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Enzyme associated with stalked particles in mitochondria and chloroplasts. It catalyses the joining of ADP and inorganic phosphate to make ATP.
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ATP synthase |
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Alternative name for a photosynthometer.
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Audus microburette
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The system of motor neurones that controls the non-conscious actions of the body. The autonomic system controls the actions of involuntary muscles and glands
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Autonomic nervous system
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Organism that makes its own food using simple inorganic molecules, such as carbon dioxide and water, and energy. Photoautotrophs (plants, some protoctists and some bacteria) use light as the source of energy. Chemoautotrophs (some bacteria) use chemical energy.
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Autotroph
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Cells in the islets of Langerhans that release insulin in response to high blood glucose levels.
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Beta cells
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A layer of connective tissue - mostly collagen - that holds an epithelium in place.
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Basement membrane
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A culture of microorganisms that takes place in a single fermentation. Products are separated from the mixture at the end of the fermentation process.
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Batch culture
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One of the waste products produced from breaking down haemoglobin.
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Bilirubin
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The number and variety of living things to be found in the world, an ecosystem or habitat.
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Biodiversity
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Any food substance in which a particularly valuable nutrient is in higher than usual levels. Golden Rice(tm) is biofortified with the accumulation of vitamin A.
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Biofortified
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Use of microorganisms to remove waste products from a location or substance. The most important example is waste water (sewage) treatment.
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Bioremediation
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The industrial use of living organisms to produce useful products. |
Biotechnology
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Pair of synapsed (joined) homologous chromosomes during prophase and metaphase of meiosis I. |
Bivalent
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The cup-shaped end of a nephron tubule.
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Bowman's capsule
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A mass of undifferentiated plant cells formed by meristem tissue extracted from the plant and grown in tissue culture.
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Callus
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Region in the medulla oblongata of the brain that controls heart rate.
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Cardiovascular centre
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The maximum stable population size that can be maintained over a period of time in a particular ecosystem. |
Carrying capacity
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Type of metabolism: biochemical reactions that produce small molecules by hydrolysis of larger molecules.
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Catabolism
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The result of all the chemical reactions taking place in the cell cytoplasm.
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Cell metabolism
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The brain and spinal cord. It has overall control over the coordination of the nervous system.
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Central nervous system
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The flow of hydrogen ions (protons) through ATP synthase enzymes. The force of this flow allows the production of ATP. Occurs across the thylakoid membranes during the light-dependent stage of photosynthesis. Also occurs across the inner mitochondrial membrane during oxidative phosphorylation (in respiration).
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Chemiosmosis
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Organism that can make its own food using energy obtained by redox reaction using simple inorganic compounds.
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Chemoautotrophs
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The points where non-sister chromatids within a bivalent join, where they cross over.
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Chiasmata
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Statistical test that can be carried out on data that are in categories. It enables the investigator to determine how closely an observed set of data corresponds to the expected data.
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Chi-squared test
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Organelles, in plant and some protoctist cells, where photosynthesis occurs.
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Chloroplasts
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A junction between neurones that uses acetylcholine as the neurotransmitter.
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Cholinergic synapse
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A hormone released by the cells of an embryo.
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Chorionic gonadotrophin
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A chart produced when substances are separated by movement of a solvent along a permeable material such as paper or gel.
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Chromatogram
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Random change to the structure of a chromosome. There are different types: inversion (a section of chromosome turns through 180°); deletion (a part is lost); translocation (a piece of one chromosome becomes attached to another); non-disjunction (homologous chromosomes fail to separate properly at meiosis 1 or chromatids fail to separate at meiosis 2; if this happens to a whole set of chromosomes, polyploidy results). The shuffling of alleles in prophase 1 is not an example of mutation.
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Chromosome mutation
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A monophyletic taxonomic group; that is, a single ancestor and all its descendants.
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Clade
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A method of classifying living organisms based on their evolutionary ancestry.
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Cladistics
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A form of learning in which two unrelated stimuli are applied to an animal, one a 'normal response' (for example salivation in the presence of food) another unrelated (for example the ringing of a bell). After repeated exposure to both stimuli together the animal will eventually respond with the normal response to the unrelated stimulus.
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Classical conditioning
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A culture of microorganisms set up in a reaction vessel and then allowed to grow without the addition of nutrients or the removal of products or wastes. ( Isolated from external conditions.) |
Closed culture
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A characteristic where both alleles contribute to the phenotype. |
Codominant |
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A coenzyme that carries acetate from the link reaction of respiration to Krebs cycle.
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Coenzyme A
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Molecules that help enzymes carry out oxidation or reduction reactions. They work by transferring a chemical group from one molecule to another. |
Coenzymes
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All the populations of different species that live in the same place at the same time, and who can interact with each other.
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Community
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The comparison of DNA sequences coding for the production of proteins/polypeptides and regulatory sequences in the genomes of different organisms of different species. Comparisons include the search for sequences that make some organisms pathogenic whilst related organisms are not.
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Comparative genome mapping
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A struggle between individuals for resources (like food or water) that are not present in amounts adequate to satisfy the needs of all the individuals who depend on those resources.
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Competition
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Genes that interact together to govern the expression of a single characteristic.
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Complementary genes
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Bacterial cells can join together and pass plasmid DNA from one bacterial cell to another. This process can take place between bacteria of different species and is of concern in terms of passing plasmid-located genes for antibiotic resistance.
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Conjugation (in bacteria)
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A dynamic process that involves the protection, management and sometimes the reclamation of ecosystems. |
Conservation
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Living organisms that feed on other living organisms.
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Consumers
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A culture of microorganisms set up in a reaction vessel to which substrates are added and from which products are removed as the fermentation process continues.
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Continuous culture
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Genetic variation, (quantitative variation) where there is a wide range of phenotypic variation within the population. There are no distinct categories. It is controlled by many genes. Examples include height in humans. |
Continuous variation
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Cutting a tree trunk close to the ground to encourage new growth.
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Coppicing
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Proteins in the cell surface membrane that allow the facilitated diffusion of simple ions to be accompanied by transport of a larger molecule such as glucose.
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Co-transporter proteins
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Food store in seeds of dicotyledonous plants. In some plants, these appear above the soil after germination and act as the first leaves.
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Cotyledons
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In voluntary muscle, the joining of a myosin head group to an actin thin filament in the presence of calcium ions.
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Cross-bridge
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Where non-sister chromatids exchange alleles during prophase I of meiosis.
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Crossing over
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Cell-signalling molecules.
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Cytokines
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The removal of the amine group from an amino acid to produce ammonia.
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Deamination
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Organisms that feed on dead organic matter. Releasing molecules, minerals and energy that then become available to other living organisms in that ecosystem. |
Decomposers |
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Removal of hydrogen atoms from a substrate molecule.
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Dehydrogenation
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The loss of polarisation across a membrane - when the membrane loses its resting potential.
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Depolarisation
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The limb of the loop of Henle that carries fluid from the cortex towards the medulla of the kidney.
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Descending limb
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Conversion of toxic substances, such as alcohol, to less toxic substances.
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Detoxification
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A condition in which the patient is unable to control blood glucose levels.
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Diabetes mellitus
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Treatment for patients with kidney failure, in which metabolic wastes and excess salts and water are removed from the blood.
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Dialysis
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The fluid used in dialysis; it consists of a complex solution that matches the composition of body fluids.
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Dialysis fluid
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A partially permeable membrane that separates the dialysis fluid from the patient's blood in a dialysis machine.
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Dialysis membrane
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Net movement of particles down their concentration gradient. It may be through a partially permeable membrane. |
Diffusion
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Hydrolyse a large molecule to smaller molecules.
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Digest
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Having two copies of chromosomes (eukaryotic cell or organism). Denoted by 2n. |
Diploid
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(qualitative variation.) Genetic variation where there are distinct phenotypic categories. Usually controlled by one gene. Examples include cystic fibrosis, shape of earlobes in humans and height in pea plants. |
Discontinuous variation
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The coiled portion of the nephron between the loop of Henle and the collecting duct.
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Distal convoluted tubule
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An enzyme capable of catalysing a condensation reaction between the phosphate group of one nucleotide and the sugar group of another. This results in DNA backbone molecules being joined together and is an essential part of recombinant DNA procedures.
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DNA ligase
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A change to the DNA structure. May be substitution of one base pair for another; inversion of a base triplet; deletion of a base pair or triplet of bases (on both strands); addition of a base pair or triplet of bases (on both strands); or a triple nucleotide repeat - a stutter.
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DNA mutation
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Characteristic in which the allele responsible is expressed in the phenotype even in those with heterozygous genotypes.
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Dominant
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Gene that codes for a dopamine receptor molecule.
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DRD4
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All the living organisms and all the non-living components in a specific habitat, and their interactions. |
Ecosystem
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Organisms that rely on external sources of heat as they can't control their internal temperature. Behavioural activities to regulate their body temperature. |
Ectotherms
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Outgoing or leading away from.
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Efferent
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Chemicals that accept electrons from another compound. They are reduced while acting as oxidising agents. |
Electron acceptors |
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A protein that transfers electrons from one molecule to another. |
Electron carriers
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A method used to separate molecules in a mixture based on their size. When a current is applied, charged molecules are attracted to the oppositely charged electrode. The smallest molecules travel fastest through the stationary phase so the molecules separate out by size.
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Electrophoresis
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A gland that secretes hormones directly into blood. |
Endocrine gland
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The transport of large molecules or fluids into the cytoplasm of the cell, by the invagination (folding inwards) of the cell surface membrane to form a vesicle.
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Endocytosis
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The tissue which lines the inside of a blood vessel or nephron.
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Endothelium
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Organisms that can control production and loss of heat to maintain their body temperature. |
Endotherms
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The ability to do work. From the Greek energos, meaning active work.
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Energy
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Double membrane. Double lipid bilayer.
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Envelope
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The combined action of biotic and abiotic factors that limits the growth of a population.
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Environmental resistance
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The interaction of genes concerned with the expression of one characteristic. One gene may block the expression of another gene. |
Epistasis
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The tissue that covers the outside of a structure.
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Epithelium
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Organisms with eukaryotic cells - protoctists, fungi, plants and animals.
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Eukaryotes
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The process of gradual change in the inherited traits passed from one generation to the next within a population. It results in the formation of new species.(Change in allele frequency.) |
Evolution
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The removal of metabolic waste (waste from the reactions inside cells) from the body.
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Excretion
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Chemical or biochemical reaction that releases heat energy. |
Exergonic
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A gland made of specialised cells that secretes substances into a ducts or surface of the body. |
Exocrine gland
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A mechanism of secretion from a cell involving vesicles that fuse to the cell surface membrane and release their contents to the outside. It uses ATP.
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Exocytosis
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A piece of tissue taken from a particular plant (which includes meristematic tissue) then sterilised in order to grow a callus in tissue culture micropropagation.
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Explant
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Diffusion that is enhanced by the action of protein channels or carriers in the cell membrane.
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Facilitated diffusion
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(1) The process of anaerobic respiration in microorganisms, used to yield specific products. For example, the anaerobic respiration of yeast is used in the production of wine from grapes.
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Fermentation
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(2) The process of culturing any microorganism in order to generate a specific product, either aerobically or anaerobically. All industrial biotechnological processes using whole microorganisms are referred to as fermentation.
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Fermentation
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When a haploid sperm cell and a haploid egg cell fuse together to create a diploid zygote. |
Fertilisation
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The set of responses in an animal that accompany the perception of threat. The response is driven by the sympathetic nervous system and adrenaline and sets the body at a higher level of capacity to respond to the threat; for example increased respiration rate in muscles and increased blood flow to muscles to prepare for explosive muscle action necessary to fight or run away. |
Fight or flight response |
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A chemical that acts as a message and binds to the cell membrane, triggering activity within the cell. |
First messenger |
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Specialised sex cells; haploid and produced by meiosis.
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Gametes
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A technique used to separate substances in a gaseous state.
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Gas chromatography
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A length of DNA that codes for one (or more) polypeptides/proteins. Some may code for RNA and regulate other genes.
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Gene
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Total genetic information possessed by the reproductive members within a population of organisms.
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Gene pool
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Possible treatment option for genetic disorders. Can be used to treat some recessive conditions but not dominant conditions such as Huntington disease. |
Gene therapy
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A small depolarisation of the membrane in a receptor cell.
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Generator potential |
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The change in allele frequency in a population, as some alleles pass to the next generation and some disappear. This causes some phenotypic traits to become rarer or more common. |
Genetic drift
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The branch of biotechnology characterised by obtaining a particular gene and inserting it into the genome of a recipient organism. Manipulation of DNA. |
Genetic engineering
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The use of DNA fragmentation and electrophoresis gives banding patterns that are unique to each individual, and that can be used in forensic identification or genetic analysis.
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Genetic fingerprinting (genetic profiling)
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A feature that is useful in tracing genes in genetic engineering. For example - antibiotic resistance genes held on bacterial plasmids are used to identify the bacteria that have taken up the required gene.
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Genetic markers
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Variation of genetic information in a gene pool.
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Genetic variation
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All the genetic information within an organism/cell.
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Genome
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The technique used to give the whole base sequence of the DNA of a particular organism.
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Genome sequencing
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The study of the whole set of genetic information in the form of the DNA base sequences that occur in the cells of organisms of a particular species.
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Genomics
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Alleles present within cells of an individual, for a particular trait/characteristic. |
Genotype
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This involves placing the gene into embryonic cells and defects genes inside cell. This technique is not currently legal and is deemed unethical. |
Germ line gene therapy
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A small network of capillaries found inside the Bowman's capsule.
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Glomerulus
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A hormone released by the alpha cells in the islets of Langerhans in the pancreas - it causes the blood glucose concentration to rise by glycogenolysis and gluconeogenesis. |
Glucagon |
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Intermediate compound produced during the Calvin cycle in the light-independent stage of photosynthesis.
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Glycerate-3-phosphate (GP) |
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Metabolic pathway. The first stage of respiration. It is anaerobic and occurs in the cytosol (cytoplasm). Although anaerobic, it involves oxidation as substrate molecules are dehydrogenated.
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Glycolysis
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A variety of rice that is genetically engineered to carry large amounts of the vitamin A precursor beta-carotene. The rice appears golden brown, unlike its non-engineered relative, which is white in colour.
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Golden Rice
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Stacks of thylakoid membranes, found in a chloroplast.
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Grana (s. granum)
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The place where an organism or population of organisms lives.
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Habitat
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A form of treatment for kidney patients in which blood is taken from a vein and passed through a dialysis machine so that exchange can occur across an artificial partially permeable membrane.
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Haemodialysis
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An arrangement of a tubule or blood vessel involving a 180° bend so that the fluid in one end of the tubule flows back past the fluid at the other end. This arrangement facilitates the exchange of materials by ensuring that there is a concentration gradient all along the tubule.
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Hairpin countercurrent multiplier
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The time taken for the concentration of a substance to drop to half its original value.
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Half-life
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Eukaryotic cell or organism having only one set of chromosomes. Denoted by n.
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Haploid
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The concept that both genotype frequencies and gene frequencies will stay constant from generation to generation, within a large interbreeding population where mating is random, there is no mutation and no selection or migration.
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Hardy-Weinberg principle
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The number of times that a normal body cell divides before undergoing apoptosis. The number of divisions is about 50.
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Hayflick constant
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Cell or individual having only one allele for a particular gene.
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Hemizygous
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An unusual blood vessel that has capillaries at both ends - it carries blood from the digestive system to the liver.
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Hepatic portal vein
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Liver cells.
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Hepatocytes
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Organism that gains its nutrients from complex organic molecules. It digests them to simpler, soluble molecules and then respires some of them to obtain energy.Cannot generate it's own food. |
Heterotroph
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Eukaryotic cell or organism that has two different alleles for a specific gene.
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Heterozygous
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Within a group individuals have a place in the order of importance within the group. This is often shown by individuals higher up in the hierarchy receiving more food or having rights of access to mate with other individuals.
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Hierarchy (social)
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Genes that control the development of the body plan of an organism.
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Homeobox genes
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The maintenance of a constant internal environment despite external changes.
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Homeostasis
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These direct the development of individual body segments. They are master genes that control other regulatory genes.
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Homeotic selector genes
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Eukaryotic cell or organism that has two identical alleles for a specific gene.
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Homozygous
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A molecule released into the blood that acts as a chemical messenger.
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Hormone
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Groups of homeobox genes. More complex organisms have more Hox clusters. This is probably due to a mutation that duplicated the Hox clusters.
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Hox clusters
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A hormone released by the human embryo. Its presence in a pregnant woman's urine can be detected to confirm pregnancy.
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Human chorionic gonadotrophin (hCG)
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Splitting of large molecules into smaller molecules with addition of water.
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Hydrolysis
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A high blood glucose concentration.
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Hyperglycaemia
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The condition of a membrane that is more highly polarised than the usual resting state. The resting potential is lower than usual.
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Hyperpolarised
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A condition in which the resting blood pressure (particularly the diastolic pressure) is raised for prolonged periods.
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Hypertension
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A low blood glucose concentration.
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Hypoglycaemia
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Where two alleles interact to control the expression of one characteristic one is epistatic and one is hypostatic. Where a homozygous recessive allele at the first locus (place on a chromosome) prevents the expression of another allele at a second locus, the alleles at the first locus are epistatic and the alleles at the second locus are said to be this.
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Hypostasis
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A portion of the brain that contains various receptors that monitor the blood. Also involved in controlling the autonomic nervous system.
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Hypothalamus
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A behaviour that an animal is capable of from birth without any learning or practice. Such behaviours appear to be very inflexible in their operation although they may often be slightly modified in individuals by some elements of learning.
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Innate behaviour
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A hormone released by the beta cells in the islets of Langerhans in the pancreas - it causes the blood glucose level to fall by glycogenesis. |
Insulin |
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Patches of endocrine tissue in the pancreas - they consist of alpha and beta cells. |
Islets of Langerhans
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Mechanism that divides populations of organisms into subgroups.
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Isolating mechanism |
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The term used to describe a method of human infant care which involves extended skin-to-skin contact and breastfeeding on demand. |
Kangaroo mother care
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Third stage of respiration. It is aerobic and in eukaryotes it occurs in the matrix of the mitochondria. A series of oxidation-reduction reactions that produces coenzymes and ATP. |
Krebs cycle
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Specialised macrophages that move around in the sinusoids and are involved in the breakdown and recycling of old red blood cells.
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Kupffer cells
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A pair of membranes that contain chlorophyll. Intergranal lamellae in the chloroplasts link the thylakoids of one granum with the thylakoids of another granum.
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Lamellae
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First stage of photosynthesis. Occurs in the thylakoid membranes of the chloroplasts. It involves using light energy to make ATP. Other products are reduced NADP and oxygen.
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Light-dependent stage
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Second stage of photosynthesis. Occurs in the stroma of the chloroplasts. Involves using ATP, reduced NADP and carbon dioxide to make organic molecules.
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Light-independent stage
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A measure of the amount of energy associated with light. The relative light intensity of a source can be calculated using the formula I = 1/d2 where d is the distance between source and object receiving the light.
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Light intensity
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A variable that limits the rate of a particular process. |
Limiting factor
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Genes for different characteristics that are present at different loci on the same chromosome are linked.
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Linkage
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Stage of aerobic respiration that links glycolysis with the Krebs cycle. In eukaryote cells it occurs in the mitochondrial matrix.
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Link reaction
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Movements of ions along a neurone close to the cell surface membrane, caused by influx or efflux of ions through the membrane.
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Local currents
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Specific position on a chromosome, occupied by a specific gene.
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Locus
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Member of a homologous pair of chromosomes that originally came from the female gamete.
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Maternal chromosome
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A portion of the brain (the brain stem) that contains centres for the control of various unconscious bodily functions and via the autonomic nervous system.
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Medulla oblongata
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Type of nuclear division. A reduction division. The chromosome number is halved. It involves two divisions. It produces cells that are genetically different from each other and from the parent cell.
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Meiosis
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Growth points in a plant where immature cells are still capable of dividing.
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Meristem
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Waste substances that may be toxic or are produced in excess by the chemical reactions inside cells.
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Metabolic waste
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A form of artificial vegetative propagation using sterile explant tissue grown to form a callus culture from which many new plants are grown by separation and growth of small parts of the callus.
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Micropropagation |
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Microscopic folds of the cell surface membrane that increase the surface area of the cell.
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Microvilli
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Antibodies that are identical because they have been produced by cells that are clones of one original cell.
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Monoclonal antibodies
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Characteristic coded for by one gene.
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Monogenic
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In phylogenetics, a group that includes an ancestral organism and all its descendent species.
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Monophyletic
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A substance that controls the pattern of tissue development. It is produced in a particular region of a developing organism. It diffuses to other cells, which then enter a specific developmental pathway.
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Morphogen
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An area of the cerebral cortex within which the neurones are responsible for driving motor functions.
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Motor area
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Refers to the innervation of a cluster of muscle fibres by a single motor neurone.
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Motor unit
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Structural change to genetic material - either to a gene or to a chromosome.
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Mutation
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A relationship between two organisms from which both benefit.
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Mutualism
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A fatty sheath around a neurone that consists of many layers of the plasma membranes of Schwann cells.
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Myelin
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Contraction of the muscle is generated from within the muscle itself. The term is used to describe the contraction of the heart, which is controlled by the action of the sinoatrial node.
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Myogenic
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The protein that forms the thick filament in muscle cells. This protein has head groups that form the cross-bridges associated with muscular contraction.
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Myosin
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Coenzyme involved in respiration. It removes hydrogen atoms from substrates. It becomes reduced NAD, which carries hydrogen atoms (protons and electrons).
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NAD
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Coenzyme involved in photosynthesis. It accepts hydrogen atoms from photolysis of water during the light-dependent stage and carries them to the light-independent stage.
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NADP
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Mechanism for evolution. Organisms that are well adapted to their environment are more likely to survive and reproduce, passing on the alleles for the favourable characteristics.
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Natural selection
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Disorderly, often accidental cell death.
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Necrosis
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A process in which any change in a parameter brings about the reversal of that change so the parameter is kept fairly constant.
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Negative feedback
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Tubules in the kidney that are used to produce urine.
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Nephrons
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Cells in the hypothalamus that are similar to neurones but release a hormone into the blood instead of a transmitter substance into a synapse.
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Neurosecretory cells
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A transmitter substance - a chemical that is released from the presynaptic membrane of one neurone to pass a signal to another neurone.
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Neurotransmitter
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The role that a species plays in an ecosystem.
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Niche
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Conversion of nitrogen gas into a form which is usable by plants, such as nitrate or ammonium ions.
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Nitrogen fixation
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Failure of members of a homologous pair of chromosomes, or of a pair of chromatids, to separate during nuclear division.
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Non-disjunction
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(therapeutic cloning.) The use of stem cells in order to generate replacement cells, tissue or organs, which may be used to treat particular diseases or conditions of humans. For example, the use of stem cells to generate replacement heart cells in patients suffering from myocardial infarction (heart attack). |
Non-reproductive cloning
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Also known as trial-and-error learning. The term is used to describe learning that takes place in animals given punishment or reward to reinforce the performance of a particular operation. Most famously, this type of learning is seen in rats and pigeons in a 'Skinner box', where operation of a lever rewards the animal with a food pellet. |
Operant conditioning |
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A section of DNA that contains structural genes, control elements and sometimes a regulatory gene. |
Operon
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Structures within cells. Each carries out a specific function.
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Organelles
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A process that occurs inside liver cells to convert ammonia combined with carbon dioxide to urea and water. |
Ornithine cycle
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Receptor cells that monitor the water potential of the blood and detect any changes. |
Osmoreceptors |
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The control and regulation of the water potential of the blood and body fluids.
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Osmoregulation
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Chemical reaction involving loss of electrons, gain of oxygen or loss of hydrogen atoms.
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Oxidation
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The formation of ATP, in the presence of oxygen, by chemiosmosis.
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Oxidative phosphorylation
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A hormone released by the posterior pituitary gland to facilitate birth and breastfeeding.
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Oxytocin
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A small organ in the abdomen that secretes digestive fluids and hormones.
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Pancreas
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A duct leading from the pancreas to carry digestive juices to the small intestine.
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Pancreatic duct
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A classification group for living organisms that includes the most recent ancestor but not all of the descendants.
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Paraphyletic group
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A membrane that is permeable to certain substances, such as water, but is not permeable to other substances.
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Partially permeable membrane
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Member of a pair of homologous chromosomes that originally came from the male gamete.
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Paternal chromosome
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The sensory and motor neurones connecting the central nervous system to the sensors and effectors around the body.
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Peripheral nervous system
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A form of treatment for kidney patients in which dialysis fluid is pumped into the body cavity so that exchange can occur across the peritoneal membrane.
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Peritoneal dialysis
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Endocytosis of large solid molecules into a cell.
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Phagocytosis
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Observable characteristics of an organism's alleles produce. |
Phenotype |
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Organism that can make its own food using energy obtained from light.
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Photoautotroph
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Enzyme-catalysed reaction where water molecules are split, using light energy. It occurs in photosystem II, during the light-dependent stage of photosynthesis. |
Photolysis |
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Process of adding a phosphate to a molecule using light energy. It takes place in the thylakoid membranes of chloroplasts, during the light-dependent stage of photosynthesis. There are two types: cyclic photophosphorylation and non-cyclic photophosphorylation. |
Photophosphorylation
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Chemicals that absorb light energy. Found in thylakoid membranes, in photosystems. Each pigment absorbs energy associated with light of a specific wavelength. Examples include chlorophyll a, chlorophyll b, carotenoids and xanthophylls. |
Photosynthetic pigments
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Apparatus to measure rate of photosynthesis by collecting and measuring the volume of oxygen produced in a certain time.
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Photosynthometer
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Group of photosynthetic pigments in the thylakoid membrane. Consists of a primary reaction centre and accessory pigments.
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Photosystems
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Group of organisms that share evolutionary ancestry.
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Phylogenetic group
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A specialised cell that makes up the lining (endothelium) of the Bowman's capsule. Podocytes have finger-like processes. They aid ultrafilitration as fluid entering the renal capsule from the blood goes through the gaps in these processes, making ultrafiltration more efficient as the podocytes do not provide a barrier to filtration.
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Podocyte
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Membrane with a potential difference across it.
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Polarised
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Characteristic coded for by many genes. Examples include height and intelligence in humans. Polygenic characteristics are more influenced by environmental factors than are monogenic characteristics.
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Polygenic
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Large polymer molecule made of many amino acids joined by peptide bonds.
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Polypeptide
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Eukaryotic organisms or cell with more than two sets of chromosomes.
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Polyploid
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All of the organisms of one species, who live in the same place at the same time, and who can breed together.
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Population
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The study of the gene pools and the allele and genotype frequencies of populations of organisms.
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Population genetics
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A mechanism is any change in a parameter that amplifies and brings about an increase in that change. |
Positive feedback |
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The hind part of the pituitary gland, which releases ADH.
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Posterior pituitary gland
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The term describes the action of the myosin head in muscular contraction. The head group attached to the actin filament tilts backwards, pulling the thick filament to overlap further with the thin filament. Energy from ATP is used up in the power stroke.
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Power stroke
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Literally means 'coming before'. In biology, a precursor molecule is one which is used in order to form another more useful molecule. For example, beta-carotene is the precursor molecule for vitamin A.
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Precursor
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Any metabolite which is formed as part of the normal growth of a microorganism. During growth the lipids, proteins, carbohydrates and waste products generated by the microorganism in order to grow in numbers are described as primary metabolites.
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Primary metabolite
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The primary photosynthetic pigments in a photosystem act as reaction centres. In PSI the primary pigment reaction centre is a molecule of chlorophyll a that has a peak absorption of 680_nm. This means that its greatest absorption is of light with a wavelength of 680_nm. In PSII the primary pigment reaction centre is a molecule of another type of chlorophyll a that has an absorption peak of 700_nm.
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Primary pigment reaction centre
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Short single-stranded sequences of DNA, around 10 bases in length. They are needed, in sequencing reactions and polymerase chain reactions, to bind to a section of DNA because the DNA polymerase enzymes cannot bind directly to single-stranded DNA fragments.
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Primer (DNA)
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Autotrophic organisms (plants, some protoctists and some bacteria) that convert light energy to chemical energy, which they then supply to consumers.
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Producers
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Primary productivity is the rate of production of new biomass by producers. It is the energy captured by their chlorophyll and used to synthesise organic molecules. This minus the energy released via their respiration is the net primary productivity - the energy available to heterotrophs through consumption of producers' biomass.
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Productivity
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Apoptosis. An orderly process by which cells die after they have undergone the maximum number of cell divisions.
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Programmed cell death
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A macromolecule. A polymer of many amino acids joined by peptide bonds. May also be called a polypeptide.
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Protein
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Eukaryotic organism classified as belonging to the kingdom Protoctista. This kingdom includes organisms that do not fit into/cannot be classified as belonging to the other four kingdoms. It includes algae, protozoa and slime moulds. Some members of this phylum are photosynthetic. Some have undulipodia and some have cilia.
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Protoctist
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Force produced as hydrogen ions flow, through ATP synthase channels, down their concentration gradient. The force causes ADP and Pi to combine and form ATP.
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Proton motive force
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Gene that can undergo mutations to become an oncogene, which induces tumour formation (cancer).
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Proto-oncogene
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A square frame used for sampling in fieldwork.
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Quadrat
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Characteristic in which the allele responsible is only expressed in the phenotype if there is no dominant allele present.
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Recessive
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A section of DNA, often in the form of a plasmid, which is formed by joining DNA sections from two different sources.
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Recombinant DNA
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Chemical reaction involving the gain of electrons, gain of hydrogen atoms or loss of oxygen atoms.
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Reduction
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The short period of time after firing during which it is more difficult to stimulate a neurone.
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Refractory period
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The process of growing bacteria on an agar plate, then transferring a replica of that growth to other plates using a sterile velvet pad. The replica plates usually contain different antibiotics. Analysis of growth patterns on the replica plates gives information about the genetic properties of the growing bacteria.
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Replica plating
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The reaction to a stimulus.
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Response
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The potential difference or voltage across the neurone cell membrane while the neurone is at rest.
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Resting potential
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An enzyme originally derived from bacteria, in which it has a role in defence against infection by viruses. The enzymes catalyse a hydrolysis reaction that breaks the phosphate-sugar backbone of the DNA double helix. The two backbones are usually broken at slightly different points on the restriction site, leaving a staggered cut known as a sticky end. The restriction site for each restriction enzyme is unique.
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Restriction enzyme
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The specific location on a stretch of DNA which is the target site of a restriction enzyme. Restriction sites are around eight bases long.
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Restriction site
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An enzyme originally derived from retroviruses. The enzyme catalyses the construction of a DNA strand using an mRNA strand as a template. Effectively the reverse of transcription.
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Reverse transcriptase
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5-carbon compound, present in small amounts in stroma of chloroplasts. It is a carbon dioxide acceptor. It is regenerated from triose phosphate.
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Ribulose bisphosphate (RuBP)
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Enzyme that catalyses the carboxylation (addition of carbon dioxide) to ribulose bisphosphate.
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Ribulose bisphosphate carboxylase (rubisco)
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Describes the process in which short fragments of single-stranded RNA bind to complementary regions on mRNA molecules and in doing so form sections of double-stranded mRNA which cannot be translated. Often triggers cellular destruction of the mRNA.
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RNA interference
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Refers to way in which the action potential appears to jump from node to node.
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Saltatory
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Organisms (like bacteria and fungi) that feed by secreting enzymes onto food, and absorbing digested nutrients across their outer walls.
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Saprotrophs
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In voluntary muscle, the span between one Z-line and the next Z-line. The Z-line is the central part of the I band, which alternates with the A band. The sarcomere is the smallest unit of contraction of voluntary muscle, consisting of the thick and thin filaments responsible for muscular contraction.
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Sarcomere
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A chemical inside the cell released in response to a hormone binding to the cell surface membrane, e.g. cAMP.
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Second messenger
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A metabolite produced by a microorganism, usually in the latter stages of growth as the culture ages. Secondary metabolites are not specifically required for the organism to grow. They usually have antibiotic properties.
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Secondary metabolite
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Genes that control the development of polarity (which end is head and which end is tail) in organisms.
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Segmentation genes
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Environmental factor that confers greater chances of surviving and reproducing on some members of the population than on others.
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Selection pressure
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The absorption of certain selected molecules back into the blood from the fluid in the nephron tubule.
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Selective reabsorption
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An area of the cerebral cortex within which the neurones associated with receiving sensory information from the receptors are found. These neurones often pass information to association areas in order to make sense of the incoming information.
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Sensory area
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Can occur with allelic forms of a gene with its locus on one of the sex chromosomes. As there are few genes on the Y chromosome in humans, usually refers to alleles of genes on the X chromosome.
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Sex linkage
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Production of new organisms involving fusion of nuclei from male and female gametes, usually from unrelated individuals. Increases genetic variation in the population.
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Sexual reproduction
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The region of the heart right atrial muscle wall that controls the synchronised rate of beating of the whole heart.
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Sinoatrial node (SAN) or sinus node
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Behaviour of organisms of a particular species living together in groups with relatively defined roles for each member of the group.
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Social behaviour
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Protein carriers embedded in the membranes of some cells, which use energy from ATP to move sodium ions and potassium ions in opposite directions simultaneously, against their concentration gradients. They are chemically gated ion channels.
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Sodium-potassium pumps
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Involves the placing of the gene in adult differentiated cells. Examples include the placing of CFTR genes into the respiratory system cells of individuals with cystic fibrosis.
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Somatic cell gene therapy
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The technique of cloning organisms involving the removal of the nucleus from an adult, differentiated cell, which is then placed into the enucleated egg cell taken from a donor organism. The cell formed is placed into a surrogate mother in order to develop. The resulting organism is a clone of the organism which provided the adult, differentiated cell nucleus.
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Somatic cell nuclear transfer
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A group of similar organisms that can interbreed and produce fertile offspring. A group of organisms with similar morphology, physiology, embryology and behaviour, and that all occupy the same ecological niche.
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Species
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A type of natural selection in which the allele and genotype frequency within populations stays the same because the organisms are already well adapted to their environment.
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Stabilising selection
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Undifferentiated cells. From the embryo, they are totipotent and are able to differentiate into any type of specialised cell found in organisms of that species. From the umbilicus and adult, these cells may become specialised into a more limited range of cell types.
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Stem cells
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Any change in the environment of an organism that causes a response.
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Stimulus
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Pores between guard cells in the epidermis of leaves.
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Stomata
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Fluid-filled matrix of chloroplasts. This is where the light-independent stage of photosynthesis takes place.
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Stroma
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Formation of ATP from ADP and Pi during glycolysis and the Krebs cycle.
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Substrate-level phosphorylation
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A directional change in a community of organisms over time.
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Succession
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The way that several small potential changes can combine to produce one larger change in potential difference across a neurone membrane.
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Summation
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The swelling at the end of a neurone where it forms a junction (synapse) with another neurone.
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Synaptic knob
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A type of joint in the skeleton characterised by the presence of a synovial membrane that produces synovial fluid to lubricate the joint. Synovial joints are found where a large movement range is required, such as the elbow and the hip.
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Synovial joint
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Cells that have receptors embedded in the plasma membrane that are complementary in shape to specific hormone molecules. Only these cells will respond to that specific hormone.
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Target cells
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Group of organisms used in a hierarchical classification. Examples are Kingdom, Phylum, Class, Order, Family.
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Taxon (pl. taxa)
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A potential difference (usually -50 mV) across the membrane. If the depolarisation of the membrane does not reach this value then no action potential is created. If the depolarisation exceeds it then more sodium ion channels open and an action potential is created.
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Threshold potential
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Inner membrane in chloroplast. Site of photosystems and ATP synthase.
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Thylakoid
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A group of cells, with a common origin and similar structures, which performs a particular function; for example, blood, bone, epithelium, muscle, nervous tissue, xylem and phloem.
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Tissue
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Also called micropropagation. The cloning of isolated cells or small pieces of plant tissue in special culture solutions, under controlled aseptic conditions.
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Tissue culture
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Stem cells that can differentiate into any type of specialised cells found in organisms of that species.
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Totipotent stem cells
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The formation of an RNA molecule, using a length of DNA as a template. Complementary base pairing is used. The enzyme RNA polymerase catalyses the reaction.
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Transcription
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A line taken through a habitat, which helps with systematic sampling of changes across a habitat.
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Transect
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Bacteria that take up DNA from their surroundings (e.g. from dead bacteria) are transformed.
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Transformation
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Stage of protein/polypeptide synthesis in which the amino acids are assembled at ribosomes. The order in which the amino acids are joined together, by peptide bonds, is determined by the sequence of codons on the mRNA, which is itself determined by the sequence of nucleotide triplets on the coding strand of a length of DNA (gene).
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Translation
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3-carbon compound formed when a molecule of glycerate phosphate is reduced, during the Calvin cycle in the light-independent stage of photosynthesis.
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Triose phosphate (TP)
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The level at which an organism feeds in a food chain.
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Trophic level
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A directional growth response in which the direction of the response is determined by the direction of the external stimulus.
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Tropism
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Filtration at the molecular level in the glomerulus of kidneys. Some molecules are filtered out of the blood of the glomerulus into the renal capsule. Molecules with relative molecular masses above 69,000 are retained in the blood capillaries.
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Ultrafiltration
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An excretory product formed from the breakdown of excess amino acids.
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Urea
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Carrier. In DNA technology, refers to the agent that carries a piece of DNA from one cell into another, e.g. a bacterial plasmid.
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Vector
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Asexual reproduction in plants making use of specialised vegetative structures that grow to form new and separate individual organisms.
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Vegetative propagation
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Channels in plasma membranes that allow the passage of ions. They respond to changes in potential difference (voltage) across a membrane and, as a result, open or close.
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Voltage-gated channels
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The transplantation of cells or organs from one species into the body of an organism of another species.
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Xenotransplantation
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Cell formed, during sexual reproduction, from the fusion of two gametes.
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Zygote
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A Non-living feature of an ecosystem |
Abiotic factor |
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A layer of cells at the bottom of a leaf stalk, which expand when stimulated by ethane, breaking cell walls and causing the leaf to fall off. |
Abscission layer |
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The number of individuals of one species in a particular area. |
Abundance |
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The bond formed when a myosin head binds to an actin filament. |
Actin-myosin cross bridge |
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A hormone secreted from the top of the adrenal glands that has many effects increasing in internal functions. |
Adrenaline |
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Process where energy is released glucose using oxygen. |
Aerobic respiration |
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Process where energy is released from glucose without oxygen present. |
Anaerobic Respiration |
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A type of anaerobic respiration that occurs in yeast ( and plants). Ethanol is the final product. |
Alcoholic Fermentation |
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One or more alternative versions of the same gene. |
Allele |
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A pair of muscle that oppose each others actions to move a bone. one contracts while the other relaxes. |
Antagonistic pair of muscles |
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A hormone which relegates the water content of the blood by controlling the permeability of the cells of the distal convoluted tubule and the collecting duct in the kidney. |
Antidiuretic hormone (ADH) |
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When the apical bud ( tip of the plant shoot), grows more then the side shoots. |
Apical Dominance |
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when individuals are selected from a population whom have desirable characteristics and breed together to pass on the traits. |
Artificial selection |
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An enzyme which catalyses the synthesis of ATP from ADP and an additional phosphate. |
ATP Synthase |
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An enzyme which catalyses the hydrolysis of ATP into ADP and a phosphate group |
ATPase |
