Ib Biology Vocabulary

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diffusion

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the passive movement of particles from a high to a low concentration

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osmosis

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the passive movement of water molecules from an area of low solute concentration to that of a high concentration through a partially permeable membrane

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active site

Back 3

region on a protein where substrates bind

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denaturation

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changing the structure of an enzyme or other protein so that it can no longer carry out its function

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gene

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a heritable factor that controls a specific characteristic

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gene

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a heritable factor that controls a specific characteristic

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allele

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a form of a gene, differing from other alleles only by a few changes in base sequence and located on the same locus as other alleles of that gene

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genome

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the whole of the genetic information of an organism

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gene mutation

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change in the base sequence of a gene (substitution, deletion, insertion)

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homologous chromosomes

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chromosomes that have the same genes, but not necessarily the same alleles of those genes

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genotype

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the genetic make-up of an organism

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phenotype

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the physical traits of an organism

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dominant allele

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the phenotype is present whether the alleles are homozygous or heterozygous

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recessive allele

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the phenotype is only affected when present in a homozygous state

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codominant alleles

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both alleles affect the phenotype (such as pink flowers)

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locus/loci

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location or position of a gene on a chromosome

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homozygous

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having two identical alleles

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heterozygous

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having two different alleles

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carrier

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an organism that has a recessive allele that does not affect the phenotype

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test cross

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homozygous recessive cross with an unknown to discover the genotype

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sex linkage

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a gene located on a sex chromosome

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clone

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a genetically identical copy of a cell or organism from a single parent

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species

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a group of organisms that can interbreed and produce fertile offspring

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habitat

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environment in which an organism lives

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population

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a number of species living in an area at the same time

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community

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a group of populations living in the same area at the same time

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ecosystem

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a community and its abiotic environment

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ecology

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the study of ecosystems

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autotroph

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an organism that is able to obtain energy by creating its own organic matter

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heterotroph

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an organism that obtains energy from organic matter from other organisms

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consumers

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organisms that ingest recently dead or living organic matter

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detritivore

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organism that ingests non-living organic matter

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saprotroph

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organism that lives on or in non-living organic matter, secreting digestive enzymes and absorbing the products of digestion

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trophic level

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position of an organism in a food chain

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evolution

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the cumulative change in the heritable characteristics of a population

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linkage group

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all of the genes that have their loci on the same chromosome type

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polygenic inheritance

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a single characteristic is controlled by two or more genes

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allele frequency

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how common an allele is

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gene pool

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all the genetic information present in the reproducing members of a population at a given time

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half life

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the amount of time it takes for one half of a radioisotope to decay

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clade

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a group of organisms that evolved from a common ancestor

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cladistics

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method of classifying living organisms based on the construction and analysis of cladograms

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sense

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strand of DNA used during transcription to make mRNA (mRNA made has the sequence of the antisense strand of DNA, and it codes for a sense strand of polypeptide during translation)

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DNA

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genetic material made of nucleotides (ATGC) in the shape of a double stranded helix and able to replicate itself

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antisense

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strand that forms the template for transcription and is transcribed

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genetic evolution

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inherited characteristics that pass from parent to child only through genes over many generations

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cultural evolution

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acquired knowledge, such as language, customs, rituals, arts, and technology, passed onto many in a social group

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homologous

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structures that have common evolutionary origin, even if their function is different

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analogous

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structures with a common function but different evolutionary origin

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autosomes

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chromosomes that are not sex chromosomes

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sex chromosome

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chromosome that determines the sex of an organism