Ib Biology Terms

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Active site

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The specific region of an enzyme to which the substrate or substrates bind.

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Allele

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A specific form of a gene, occupying the same gene locus as other alleles of that gene, but differing from other alleles by small differences in its base sequence.

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Autotroph

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Organisms that use an external source of energy(light or chemical) to synthesise organic compounds from inorganic substances.

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Carrier

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An individual that has a recessive allele of a gene.

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Carrying capacity

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The maximum population size that can be supported by the enivornment.

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Cell respiration

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Release of energy in the form of ATP from the controlled breakdown of organic compounds within the cell.

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Clone

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A group of genetically identical organisms or a group of cells derived from a single parent cell.

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Codominant alleles

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Pairs of alleles that both affect the phenotype when present in the heterozygous state.

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Community

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A group of population living and interacting with each other in an area.

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Degenerate

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Having more than one base triplet code for one amino acid.

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Denaturation

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A structural change in a protein that results in a loss (usually permanent) of its biological properties.

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Detritivore

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Organisms that feed on dead organic matter by ingesting it.

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Diffusion

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THe passive movement of a substance from a region of high concetration to a region of low concentration.

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Dominant allele

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An allele that has the same affec on the phenotype when in either the homozygous or heterozygous state.

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Ecology

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The study fo relationships between living organisms and between living organisms and their environment.

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Ecosystem

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A community and its abiotic environment

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Enzyme

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Globular protein capable of catalysing a specific chemical reaction.

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Evoultion

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The process of cumulative change in the heritable characteristics or a population.

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Excretion

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Removal from the body of waste products of metabolis.

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Gene

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A heritable factor that controls a specific characteristic.

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Gene mutation

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A change in the sequence of bases in a gene.

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Genetic screening

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Testing an individual for the presence or absence of an allele.

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Genome

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The whole of the genetic information of an organism.

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Genotype

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The alleles possessed by an organism.

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Habitat

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The environment in which a species normally lives or the location of a living organism.

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Heterozygous

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Having two different alleles at a gene locus.

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Heterotroph

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Organism that obtains its energy from organic molecules that it has consumed.

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Homologous chromosomes

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A pair of chromosomes with the same genes but not necessarily the same alleles of those genes.

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Homozygous

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Having two identical alleles at a gene locus.

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Locus

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The specific position on a homologous chromosome of a gene.

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Organelle

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A discrete structure within a cell that carries out a specific function.

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Organic

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Compounds containing carbon found in organims (Excluding hydrogencarbonates, carbonates, and oxides of carbon).

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Organ

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A group of tissues that form a single structure and which work together to carry out a function.

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Organ system

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A group of organs that work together to carry out a function.

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Osmosis

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The passive movement of water molecules across a partially permeable membrane from a region of lower solute concetration to a region of higher solute concetration.

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Pathogen

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An organism or virus that causes a disease.

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Phenotype

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The characteristics of an organism.

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Population

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A group of organisms of the same species that live in the same area at the same time.

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Random sample

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A sample of a population in which every individual has an equal chance of being selected.

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Recessive allele

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An allele that only has an effect on the phenotype when it is homozygous state.

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Saprotroph

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Organism that feeds of on dead organic matter by secreting digestive enzymes onto it and absorbing the products of digestion.

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Sex Linkage

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The pattern of inheritance characteristics of genes located on the se chromosomes.

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Species

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A group of organisms that can interbreed to produce fertile offspring.

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Test cross

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Testing a phenotypically dominant phenotype to determine if it is heterozygous or homozygous.

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Tissue

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A group of similar cells organised into a functional unit.

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Trophic level

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The position of an organism in a food chain.

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Universal

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Found in all organisms

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copulation

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biological term for sexual intercourse; the act of inserting the penis into the vagina

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Fertilization

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The fusion of the sperm and the egg to form a zygote.