HL BIO genetics test stuff (other than quiz)
Gregor Mendel
Father of modern genetics. used garden peas to explain the inheritance of characteristics. 1865 he published his work.
Artificial Pollination
paint brush and transferring the pollen (male gamete) on the anther of one plant to the stigma of another where it will then travel down the style and fertilize an egg. the anthers on the fertilized plant will be removed to prevent self-fertilization. It is then enclosed in a paper bag to prevent insects or wind from transferring the pollen. This all creates less genetic diversity.
Two different purebred varieties results in
only one feature being expressed, not a blend.
self-fertilized the offspring results in
the offspring expressing two different traits in a ratio of ~ 3:1
Mendels 3 rules
Law of segregation: when gametes form, alleles are separated so that each gamete carries only one allele for each gene.
Law of independent assortment: the segregation of alleles for one gene occurs independently to that of any other gene.
Principal of dominance: Recessive alleles will be masked by dominant alleles.
Genotype
symbolic representation of a pair of alleles possessed by an organism
Phenotype
characteristics or traits of an organism
Dominant allele
an allele that has the same effect on the phenotype whether is is paired homozygous or heterozygous. Dominant alleles are always expressed in the phenotype
Recessive allele
an allele that only has an effect on the phenotype when present in the homozygous state. (aa has no dominant allele to mask it)
Carrier
an individual who has a recessive allele of a gene that does not have an effect on their phenotype (Aa albinism but has pigmented skin, an ancestor must have been albino and some offspring might be too. if both parents are unaffected but are carriers their kids could have it too). They are heterozygous
Pure-breeding
individuals of the same phenotype that when crossed with each other produce offspring which also have all the same phenotype. they are homozygous.
Test cross
testing a suspected heterozygous thing by crossing it with a known homozygous recessive (aa). impossible to tell if an organism is AA or Aa until they produce offspring.
Locus
an area of a chromosome that contains a gene. aka particular position on homologous chromosome of a gene.
Factors that effect phenotypes
genotype only: eye colour
environment interacting with genotype: skin colour
environment only: leaned behaviour, acquired characteristic
Phenotypic Plasticity
the ability to express a phenotype in response to an environmental change. can generate changes in:
Physiology, Morphology, Behaviour, Phenology: