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FlashCards por joannalivesey, atualizado more than 1 year ago
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Criado por joannalivesey
quase 10 anos atrás
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| Questão | Responda |
| ecosystem | more or less self-contained functional unit in ecology made up of all the interacting abiotic and biotic factors in an area |
| population | all the organisms of one species in a habitat |
| community | all the organisms of all the different species that live in the same area |
| habitat | place where an organism lives |
| Biotic factor | living factor of the organism's environment e.g. mutualism, disease and predation. |
| abiotic factor | non-living factor of the organism's environment e.g. temperature, pH, rainfall |
| niche | organisms role in an ecosystem governed by adaptation to biotic and abiotic conditions |
| percentage cover | estimate of the area within a quadrat that a particular plant species covers |
| frequency | likelihood of a particular species occurring in a quadrat |
| abundance | number of individuals of a species within a given space (measured by frequency, %cover and population density) |
| population density | number of individuals of a species present per metres squared (number of them in quadrat) |
| biodiversity | range and variety of living organisms within a particular area |
| Gene | section of DNA that codes for a polypeptide |
| Alleles | different versions of the same gene |
| Locus | specific position of a gene on a chromosome |
| Gamete | sex cells with haploid number of chromosomes |
| Homozygous | when an individual contains two identical alleles of the gene |
| Heterozygous | an individual that has two different alleles of the same gene |
| Dominant allele | always expressed in the phenotype if present |
| Recessive allele | only expressed in the phenotype if the individual is homozygous |
| Co-dominant alleles | both alleles contribute to the phenotype as both are equally dominant |
| Phenotype | characteristics of an organism resulting from both genotype and environment |
| Genotype | genetic constitution of an organism |
| Monohybrid inheritance | inheritance of a single characteristic controlled by one gene |
| Multiple alleles | when there are more than two alleles for a gene |
| succession | Change in species composition in an area over time due to environmental factors. Conditions change due to species present |
| allele frequency | number of times an allele occurs within the gene pool |
| biomass | total mass of living material in a specific area at a given time (usually measured as dry mass as amount of water in an organism is very variable) |
| climax community | a stable community of the organisms that make up the final stage of ecological succession |
| directional selection | selection that selects against one extreme in phenotype, shifting the mode. It normally occurs in a changing environment |
| stabilising selection | selection that selects against both extremes in phenotype, reducing the variation around the mode, which stays the same. It normally occurs in a stable environment |
| ectotherm | an animal that uses the environment and behaviour to regulate its body temperature |
| endotherm | an animal that maintains a constant body temperature by physiological mechanisms |
| effector | an organ that responds to stimulation by a nerve impulse, resulting in a change or response |
| receptor | a cell adapted to detect changes in the environment |
| gene pool | total number of alleles in a particular population at a specific time |
| gene therapy | where defective alleles are replaced with functional ones to treat genetic disorders |
| generator potential | depolarisation of the membrane of a receptor cell as a result of a stimulus |
| Conduction | The direct transfer of heat energy through matter. Heat causes particles to vibrate and gain kinetic E, making adjacent particles vibrate too. Occurs mainly in solids. |
| convection | Heat transfer due to movement of the warmed matter itself. Heat causes them to expand and move, carrying the heat that they absorbed with them. Occurs in fluids |
| Radiation | transfer of heat by infra-red waves, how we lose most of our heat |
| Evaporation | conversion of liquid water to vapour. Requires lots of heat energy which is gained by the water as it evaporates |
| Glycogenolysis | Breakdown of glycogen (stored in liver and muscle cells) to glucose |
| Gluconeogenesis | production of new glucose from sources other than carbohydrates e.g. lactate, glycerol and amino acids |
| Glycogenesis | conversion of glucose to glycogen (stored in the liver) |
| homeostasis | the maintenance of a more or less constant internal environment |
| interspecific competition | competition between organisms of different species |
| intraspecific competition | competition between organisms of the same species |
| introns | sections of non-coding DNA within a gene |
| mutation | change in the DNA base sequence |
| negative feed back | a change in the normal levels initiates a response which acts against the change to restore levels to normal |
| oncogenes | mutated versions of proto-oncogenes that result in increased cell division leading to growth of a tumour |
| pioneer species | The first species to colonise an inhospitable habitat. They are tolerant to hostile conditions, and alter them making them less hostile (e.g. add humus, increase soil nutrient content, change the pH) |
| recognition sequence | short and palindromic section of double stranded DNA to which a restriction endonuclease with a complementary active site can bind and cut |
| refractory period | period during which the axon membrane cannot be depolarised as Na+ ion channels are closed. NO NEW actions potentials can be initiated |
| salutatory conduction | occurs along myelinated neurones. localised currents arise between adjacent nodes of Ranvier which allow action potential to ‘jump’ from one node to the next |
| saprobiotic bacteria | secrete enzymes which break down dead/decaying matter extracellularly, before absorbing the products of digestion |
| selective breeding | breeding of an organism by human selection of parents in order to increase/eliminate certain characteristics |
| Totipotent | unspecialised and capable of expressing all its genes (e.g. embryonic stem cells)- can differentiate into any cell of that organism |
| Multipotent | cells that can only differentiate into a few closely related cell types (e.g. most adult stem cells) |
| Housekeeping genes | expressed in each of the organism’s cells e.g. genes coding for respiration enzymes |
| Somatic cells | cells that are not involved in reproduction |
| stem cells | cells that are unspecialised, can all divide and renew themselves over long periods and can develop into other specialised cell types. (two types: embryonic and adult) |
| sex-linked gene | gene carried on a sex chromosome (usually X as Y is much shorter) |
| homologous chromosomes | Chromosomes with same genes at same loci |
| what is a transect? | A method of systematic sampling. Line through habitat along which organisms are sampled and measurements are taken |
| monoculture | Same crop grown in large numbers over large area |
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