Unit 5 Heredity Test Review

The form of a gene that is always expressed if present is the _______ form.

• recessive

• dominant

• homologous

• heterozygous

Two heterozygous purple-flowering pea plants are crossed. If purple is dominant over white, what are the expected phenotypic results?

• 100% purple

• 75% purple

  25% white

• 50% purple

  50% white

• 25% purple

  75% white

What law BEST explains why an organism with 'Tt' will show only the dominant phenotype?

• Law of Dominance

• Law of Segregation

• Law of Independent Assortment

• Chromosome Theory of Inheritance

If an organism inherits one dominant allele and one recessive allele for eye color, their genotype would be:

• haploid

• homozygous

• heterozygous

• homologous

Two parents have the genotype Gg for a genetic disorder caused by a recessive allele. What is the chance that their children will inherit the disorder?

• 25%

• 50%

• 75%

• 100%

Which Mendelian law of inheritance states that organisms inherit two copies of each gene and donate one copy to each of their offspring?

• Law of Dominance

• Law of Segregation

• Law of Independent Assortment

• Chromosome Theory of Inheritance

In pigs, the allele for a wavy, rough coat (R) is dominant to the allele for a soft, fine coat (r). A rough coat boar and a soft coat sow mate. They produce several litters, 50% are rough coat and 50% are smooth coat. What must be the genotypes of the parents to create this phenotypic ratio?

• RR × rr

• Rr x rr

• RR x Rr

• Rr x Rr

Imagine two heterozygous parents.  Each has a dominant allele (B) for brown eyes and a recessive allele (b) for blue eyes.  What would the genotypic ratio of the offspring be?

• 100% Bb

• 50% BB

  50% Bb

•  25% BB

  50% Bb

  25% bb

• 50% Bb

  50% bb

The genotype TT is considered to be:

• homozygous

• heterozygous

The genotype Tt is considered to be:

• homozygous

• heterozygous