Genetic Inheritance/ Key definitions

• What is an allele?

  • A version of a gene
• What does a genotype do?

  • Tells us the alleles present
• What is heterozygous?

  • Two different alleles
• What is a dominant allele?

  The one that shows in the phenotype even if one copy is present
• What is a recessive allele?

  Allele that only shows up in phenotype if two are present
• What is homozyguos?

  When both inherited alleles are the same (two dominants or two recessive)
• What is a dominant/recessive allele?

  • Dominant: an allele that only needs to be inherited from one parent for its trait to be expressed in an organism’s phenotype
  • Recessive: an allele that only affects an organism’s phenotype if two copies of it are inherited one from each parent
• What is a phenotype?

  Characteristics observed in an individual (eye colour)
• What is a gene?

  • Short section of DNA that codes for a specific protein
• What is a chromosome?

  • DNA structures found in the nucleus
• What is a gamete?

  • Organisms reproductive cells containing 23 chromosomes.
  • Egg and Sperm
• What are the 3 key points needed for drawing genetic diagrams?

  • Parents genotype and phenotype
  • Gametes genotype
  • Offspring's genotype and phenotype