IB Define terms

  1. Define diffusion.
    Diffusion is the passive movement of particles froma region of high concentration to a region of lowconcentration.
  2. Define osmosis.
    Osmosis is the passive movement of watermolecules, across a partially permeable membrane,from a region of lower solute concentration to aregion of higher solute concentration.
  3. Define enzyme
  4. Define Active site
  5. Define denaturation
    Denaturation is a structural change in a proteinthat results in the loss (usually permanent) of itsbiological properties.
  6. Define cell respiration.
    Cell respiration is the controlled release of energyfrom organic compounds in cells to form ATP.
  7. Define gene.
    Gene: a heritable factor that controls a specificcharacteristic.
  8. Define allele.
    Allele: one specific form of a gene, differing fromother alleles by one or a few bases only andoccupying the same gene locus as other alleles ofthe gene.
  9. Define genome.
    Genome: the whole of the genetic information ofan organism.
  10. Define gene mutation.
  11. Define homologous chromosomes.
  12. Define genotype.
    Genotype: the alleles of an organism.
  13. Define phenotype.
    Phenotype: the characteristics of an organism.
  14. Define dominant allele.
    Dominant allele: an allele that has the same effecton the phenotype whether it is present in thehomozygous or heterozygous state.
  15. Define recessive allele.
    Recessive allele: an allele that only has an effect onthe phenotype when present in the homozygous state.
  16. Define codominant alleles.
    Codominant alleles: pairs of alleles that both affect the phenotype when present in a heterozygote
  17. Define locus.
    Locus: the particular position on homologous chromosomes of a gene.
  18. Define homozygous.
    Homozygous: having two identical alleles of a gene.
  19. Define heterozygous
    Heterozygous: having two different alleles of a gene.
  20. Define carrier
    Carrier: an individual that has one copy of arecessive allele that causes a genetic disease inindividuals that are homozygous for this allele.
  21. Define test cross
    Test cross: testing a suspected heterozygote bycrossing it with a known homozygous recessive.(The term backcross is no longer used.)
  22. Define sex linkage.
  23. Define clone.
    Clone: a group of genetically identical organisms ora group of cells derived from a single parent cell.
  24. Define species.
    Species: a group of organisms that can interbreed and produce fertile offspring..
  25. Define habitat.
    Habitat: the environment in which a speciesnormally lives or the location of a living organism.
  26. Define population.
    Population: a group of organisms of the samespecies who live in the same area at the same time.
  27. Define community
    Community: a group of populations living and interacting with each other in an area.
  28. Define ecosystem.
    Ecosystem: a community and its abioticenvironment.
  29. Define ecology
    Ecology: the study of relationships between living organisms and between organisms and their environment
  30. Define trophic level
  31. Define evolution
    Evolution is the cumulative change in the heritablecharacteristics of a population.
  32. Define pathogen
    Pathogen: an organism or virus that causes adisease.
  33. Define resting potential
  34. Define action potential
  35. AHL ONLY: Define transpiration
    Transpiration is the loss of water vapour from theleaves and stems of plants.
  36. AHL ONLY: Define linkage group
  37. AHL ONLY: Define polygenic inheritance.
  38. AHL ONLY: Define active and passive immunity
    Active immunity is immunity due to the productionof antibodies by the organism itself after the body’sdefence mechanisms have been stimulated by antigens.

    Passive immunity is immunity due to the acquisitionof antibodies from another organism in which active immunity has been stimulated, including via theplacenta, colostrum, or by injection of antibodies
  39. AHL ONLY: Define excretion
    Excretion is the removal from the body of the wasteproducts of metabolic pathways.
  40. AHL ONLY: Define osmoregulation
    Osmoregulation is the control of the water balanceof the blood, tissue or cytoplasm of a living organism.
  41. Define allele frequency
  42. Define gene pool
  43. Define half life
  44. AHL ONLY: Define clade and cladistics.
  45. Define biomass.
  46. Define gross production
  47. Define net production
  48. Define biomagnification
    Biomagnification is a process in which chemical substances become more concentrated at each trophic level.
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IB Define terms
all the IB define terms