Genetics Quiz for Grade 6

What is the difference between homozygous and heterozygous?

• A homozygous genotype has identical alleles for a trait, while a heterozygous genotype has different alleles.

• A homozygous genotype always results in a dominant trait, while a heterozygous genotype always results in a recessive trait.

• A homozygous genotype only occurs in males, while a heterozygous genotype only occurs in females.

• A homozygous genotype involves two traits, while a heterozygous genotype involves only one trait.

What does a dominant allele do?

• It is only expressed when paired with another dominant allele.

• It is masked by the presence of a recessive allele.

• It determines the trait even if only one copy is present.

• It has no effect on the phenotype unless two copies are present.

What is the expected phenotype ratio from an Ss x Ss cross?

• 75% short-haired

• 25% long-haired

• 50% short-haired

• 50% long-haired

What is the expected phenotype ratio from an Hh x hh cross?

• 50% red fruit

• 50% yellow fruit

• 75% red fruit

• 25% yellow fruit

What is the probability of having a tongue roller child from a non-roller and a heterozygous parent?

• 25%

• 50%

• 75%

• 100%

What do Roman numerals represent in pedigree charts?

What does II-4 represent in a pedigree chart?

What is the genotype of a hornless cattle?

• HH

• hh

• Hh

What is the expected phenotype ratio from a Bb x Bb cross?

• 75% Brown Eyes

• 25% Blue Eyes

• 50% Brown Eyes

• 50% Blue Eyes

What is the expected phenotype ratio from a Rr x rr cross?

• 50% Round

• 50% Wrinkled

• 75% Round

• 25% Wrinkled