F215 Definitions Flashcards
Genetic Code
The sequence of bases in DNA that code for specific polypeptides.
Allele
An alternative version of a gene.
Locus
Specific position of a gene on a chromosome.
Phenotype
Observable characteristics of an organism.
Genotype
Alleles expressed within cells of an individual for a particular characteristic.
Dominant
Characteristic in which the allele is responsible is expressed in the phenotype even in those with heterozygous genotypes.
Codominant
A characteristic where both alleles contribute to the phenotype.
Recessive
Characteristic in which the allele responsible is only expressed in the phenotype if there is no dominant allele present.
Linkage
Genes for different characteristics that are present at different loci on the same chromosome are linked.
Crossing over
Where non-sister chromatids exchange alleles during prophase 1 of meiosis.
Continuous 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 e.g height.
Discontinuous Variation
Qualitative variation where there are distinct phenotypic categories. Usually controlled by one gene e.g blood type.
Aseptic Techniques
Any measures taken to prevent contamination by foreign and unwanted microorganisms.
Biotechnology
Industrial use of living organisms to produce food, drugs or other useful products.
Recombinant DNA
A section of DNA often in the form of a plasmid which is formed by joining DNA sections from two different sources.
Gene Therapy
Any therapeutic technique where the functioning allele of a particular gene is placed in cells of an individual lacking alleles of that particular gene. Used to treat recessive conditions.
Ecosystem
All the living and non-living components in a specific habitat and their interactions.
Biotic Factor
Living components of an ecosystem.
Abiotic Factor
Non-living components of an ecosystem.
Producer
Autotrophic organisms that convert light energy to chemical energy which they then supply to consumers.
Consumer
Living organisms that feed on other living organisms.
Decomposer
Organisms that feed on dead matter by secreting enzymes, releasing molecules, minerals and energy that then become available to other living organisms in that ecosystem.
Tropic Level
The level at which an organism feeds in a food chain.
Carrying Capacity
The maximum population size that can be maintained over a period of time in a particular habitat.
Interspecific Competition
Competition between individuals of different species for resources.
Intraspecific Competition
Competition between individuals of the same species for resources.
Conservation
Maintenance of biodiversity, including diversity between species, genetic diversity within species, and maintenance of a variety of habitats and ecosystems.
Preservation
Acting to keep biodiversity etc the same.
Tropism
Directional growth response in which the direction of the response is determined by the direction of the external stimulus.
Regulatory Gene
Makes repressor protein/transcription factor. Controls the expression of a structural gene.
Structural Gene
Makes enzymes.
Homozygous
Two identical alleles.
The Biological Species Concept
A group of similar organisms that can interbreed and produce fertile offspring, the group is therefore reproductively isolated from others. PROBLEMS: Not all organisms reproduce sexually, members of the same species can look different, can’t be used for extinct species or fossils.
The Phylogenetic Species Concept
Group of organism that have similar morphology, physiology, embryology and behaviour occupy the same ecological niche. This can be used for all organisms even if not known if species can interbreed. Closely related species have more similar DNA base sequences and molecular structures than less closely related species. Organisms with most similar DNA = clade.
Natural Selection
Occurs naturally, due to selection pressures, traits selected are beneficial for survival, several traits are selected together, slower process of change.
Artificial Selection
Carried out by humans, due to selective breeding, traits selected are beneficial for humans, often trait is selected on its own, faster process of change.
Reproductive Cloning
Production of new individuals either naturally or artificially.
Non-Reproductive Cloning
Also known as Therapeutic. Production of cloned cells to produce cells, tissues and organs to replace those damaged.
