Alleles / Dominant / Heterozygous / Phenotypes

• What is the focus of today's video?

  It is a continuation of the last video on DNA.
• What is an allele?


  An allele is a different version of the same gene.
• What are the differences between dominant and recessive alleles?


  Dominant alleles are expressed over recessive alleles.
• What is the difference between homozygous and heterozygous?


  Homozygous means having two identical alleles, while heterozygous means having two different alleles.
• What is a gene?


  A gene is a segment of DNA that codes for a particular type of protein.
• How do genes determine characteristics?


  Genes we inherit determine the characteristics we develop.
• Can a single gene determine a trait?


  Yes, sometimes traits are determined by a single gene.
• Give an example of a trait determined by a single gene.

  Fur color in mice and red-green color blindness in humans.
• How are most characteristics determined?

  Most characteristics are determined by several different genes that interact with each other.
• What does it mean when we say there are multiple forms of the same protein?

  It means there are different genetic codes for each form, called alleles.
• How many copies of every gene do we have?


  We have two copies of every gene, one from each parent.
• What does it mean to be homozygous for an allele?


  It means both alleles for that gene are the same.
• What does it mean to be heterozygous for an allele?


  It means having two different alleles for that gene.
• If a mouse is heterozygous for fur color with one allele coding for purple fur and the other for green fur, what color will it be if purple is dominant?


  The mouse will be purple.
• What is the only way to have a green mouse in this scenario?


  Both alleles must be for green fur, making it homozygous recessive.
• When is a dominant allele expressed?


  A dominant allele is expressed whenever it is present.
• What is the definition of genotype?


  The genotype is the entire collection of alleles that an organism has.
• How do different genotypes relate to phenotypes using the example of mice?


  Mice with different genotypes can have the same phenotype if they express the same trait.
• What is phenotype?


  Phenotype is the characteristics that result from an organism's genotype.
• If a heterozygous mouse and a homozygous dominant mouse are both purple, what can we say about their phenotypes?


  They have the same phenotype despite having different genotypes.
• How does the phenotype of a homozygous recessive mouse differ from that of a purple mouse?


  The homozygous recessive mouse is green, while the purple mouse is purple.
• What are the key terms related to genetics discussed in the video?

  • Allele
  • Dominant
  • Recessive
  • Homozygous
  • Heterozygous
  • Genotype
  • Phenotype
• What will the next video cover?

  It will cover genetic diagrams.