DNA

• What is an allele?

  A variant form of a gene
• What is the difference between dominant and recessive alleles?

  Dominant alleles are expressed over recessive ones
• What does homozygous mean?

  Having two identical alleles for a gene
• What does heterozygous mean?

  Having two different alleles for a gene
• What is the relationship between genes and DNA?

  A gene is a segment of DNA coding for proteins
• How do genes determine characteristics?

  They code for proteins that influence traits
• How are most characteristics determined?

  By the interaction of several different genes
• Why do humans have different heights?

  Multiple genes interact to determine height
• What are alleles?

  Different versions of the same gene
• How many copies of each gene do we have?

  Two copies, one from each parent
• What does it mean to be homozygous for an allele?

  Having two identical alleles for that gene
• What does it mean to be heterozygous for an allele?

  Having two different alleles for that gene
• If a mouse is heterozygous for fur color with one allele for purple and one for green, what color will it be if purple is dominant?

  It will be purple
• What is required for a mouse to be green?

  Both alleles must be for green fur
• What is the definition of genotype?

  The entire collection of alleles an organism has
• What is the definition of phenotype?

  The observable characteristics from genotype
• How can two mice have the same phenotype but different genotypes?

  They can have different alleles but express the same trait
• Why does the homozygous recessive mouse have a different phenotype?

  It has different alleles than the others
• What are the key terms related to genetics discussed in the video?

  • Allele
  • Dominant and recessive
  • Homozygous and heterozygous
  • Genotype and phenotype
• What is the relationship between genotype and phenotype?

  • Genotype: collection of alleles
  • Phenotype: observable characteristics
  • Different genotypes can lead to the same phenotype
• How do dominant and recessive alleles interact in determining traits?

  • Dominant alleles are expressed over recessive ones
  • Recessive traits appear only when both alleles are recessive
• What is the significance of having two alleles for each gene?

  • Provides genetic variation
  • Allows for different combinations of traits
  • Influences phenotype expression