Cards (23)

    • What should you be able to describe by the end of the video?
      Dominant and recessive alleles
    • What do homozygous and heterozygous refer to?
      Types of genotypes based on alleles
    • What is a key fact about human chromosomes?
      • Normal human cells contain 23 pairs of chromosomes
      • Each pair consists of one chromosome from the father and one from the mother
    • What are genes?
      Sections of DNA on a chromosome
    • How many copies of every gene do humans have?
      Two copies of every gene
    • What is the gene that controls earwax?
      The earwax gene
    • What are alleles?
      Versions of a gene
    • What does the allele for wet earwax symbolize?
      Capital E
    • What does the allele for dry earwax symbolize?
      Lowercase e
    • What is the genotype of a person with two copies of the allele for dry earwax?
      Lowercase e lowercase e
    • What does homozygous mean?
      Having two copies of the same allele
    • What does phenotype refer to?
      Characteristics caused by alleles
    • What is the phenotype of a person with two alleles for dry earwax?
      Dry earwax
    • What is the genotype of a person with two alleles for wet earwax?
      Capital E capital E
    • What is the phenotype of a person with two alleles for wet earwax?
      Wet earwax
    • What is the genotype of a person with one allele for wet earwax and one for dry earwax?
      Capital E lowercase e
    • What does heterozygous mean?
      Having two different alleles
    • What phenotype does a heterozygous person for earwax have?
      Wet earwax
    • What is a dominant allele?
      Shows in phenotype with one copy
    • What is a recessive allele?
      Shows in phenotype only with two copies
    • How are most characteristics controlled?
      • Most characteristics result from many genes acting together
      • Example: Height is influenced by multiple genes
    • What will the next video cover?
      Genetic crosses and allele inheritance
    • Where can you find questions on this topic?
      In the vision workbook