Inheritance

• What is a chromosome?

  A long DNA molecule containing genes
• How many pairs of chromosomes do humans have?

  23 pairs
• What is a locus?

  The position of a gene on a chromosome
• What is an allele?

  Different form of a gene
• What is a gene?

  A sequence of bases coding for amino acids
• What is a genotype?

  Alleles of a gene that's inherited
• What is a phenotype?

  Observable physical characteristic
• What does homozygous mean?

  Having two identical alleles at a locus
• What does heterozygous mean?

  Having two different alleles at a locus
• What is a dominant allele?

  Always expressed if inherited
• What is a recessive allele?

  Only expressed if two copies are present
• What is incomplete dominance?

  Both alleles influence the phenotype
• What are the possible flower colors in snapdragons?

  • Red flowers (RR)
  • White flowers (rr)
  • Pink flowers (Rr)
• How are dominant alleles represented?

  With capital letters, e.g., B
• How are recessive alleles represented?

  With lowercase letters, e.g., b
• What are the genotypes for eye color if Bb, bb, and BB are used?


  Bb, bb, BB
• How does incomplete dominance affect phenotype in snapdragons?

  It produces a third phenotype in heterozygotes