Intro to Genetics

What is the phenotype?

• The genetic makeup of an organism.

• The observable physical or biochemical characteristics of an organism, determined by its genotype.

• The process by which traits are passed from parents to offspring.

• The study of how organisms interact with their environment.

What is an allele?

• An allele is a variant form of a gene that can produce different traits.

• An allele is a type of chromosome that determines the sex of an organism.

• An allele is a protein that helps in the synthesis of DNA.

• An allele is a cellular structure that carries genetic information.

What is the purpose of a test cross?

• To determine the genotype of an organism with a dominant phenotype by crossing it with a homozygous recessive individual.

• To identify the phenotypic ratio of offspring in a dihybrid cross.

• To assess the environmental impact on genetic traits in a population.

• To evaluate the effectiveness of a breeding program in agriculture.

What is a carrier in genetics?

• An individual who has two copies of a dominant allele for a trait.

• An individual who has one copy of a recessive allele for a trait but does not exhibit the trait themselves.

• An individual who exhibits the trait associated with a recessive allele.

• An individual who has no alleles for a specific trait.

What is the difference between genotype and phenotype?

• Genotype refers to the physical expression of traits, while phenotype refers to the genetic makeup.

• Genotype refers to the genetic makeup, while phenotype refers to the physical expression of that genetic makeup.

• Genotype and phenotype are the same and can be used interchangeably.

• Genotype refers to the observable characteristics, while phenotype refers to the underlying genetic code.

What is a dominant allele?

• An allele that expresses its trait only when two copies are present in the genotype.

• An allele that can mask the effect of a recessive allele in the genotype.

• An allele that is always expressed regardless of the environment.

• An allele that expresses its trait even when only one copy is present in the genotype.

What does it mean if an organism is homozygous recessive?

• An organism has two dominant alleles for a trait (e.g., RR).

• An organism has one dominant and one recessive allele for a trait (e.g., Rr).

• An organism has two recessive alleles for a trait (e.g., rr).

• An organism has no alleles for that trait.

What is the law of segregation?

• The law of segregation states that traits are inherited independently of one another.

• The law of segregation states that during the formation of gametes, the two alleles for a trait separate from each other.

• The law of segregation states that dominant alleles always mask recessive alleles.

• The law of segregation states that alleles are blended together in offspring.

What does heterozygous mean?

• Having two identical alleles for a particular gene (e.g., RR)

• Having two different alleles for a particular gene (e.g., Rr)

• Having no alleles for a particular gene

• Having three alleles for a particular gene

What is a recessive allele?

• An allele that expresses its trait only when two copies are present in the genotype.

• An allele that always expresses its trait regardless of the other allele.

• An allele that can mask the expression of another allele.

• An allele that is only found in the mitochondrial DNA.