biogenetics

• gamete

  • is a sex cell
  • for humans sperm/egg for male/female
• • Chromosomes are contained inside the cell's nucleus. These are long threads of DNA, which are made up of many genes.
• • A gene is a small section of DNA on a chromosome, that code for a particular sequence of amino acids, to make a specific protein. It is the unit of heredity, and may be copied and passed on to the next generation.
• Alleles are different versions of the same gene. For example, the gene for eye colour has an allele for blue eye colour and an allele for brown eye colour
• • The genotype is the collection of alleles that determine characteristics and can be expressed as a phenotype.
• dominant allele 


  An allele that always expresses itself whether it is partnered by a recessive allele or by another like itself.
• recessive allele


  Describes the variant of a gene for a particular characteristic which is masked or suppressed in the presence of the dominant variant. A recessive gene will remain dormant unless it is paired with another recessive gene.
• Homozygous alleles are both identical for the same characteristic for example AA/aa
• • Heterozygous alleles are both different for the same characteristic, for example Aa.