Genetics Monohybrid Crosses Quiz

Mendel proposed that traits observed in pea plants resulted from a combination of "factors" inherited from each parent. His description of these "factors" can be considered the first scientific definition of the role of —

• ribosomes

• meiosis

• genes

• cell nuclei

Which of the following traits of a dog is inherited from its parents?

• the presence of fleas in its fur

• the color of its fur

• the ability to sit up and beg

• the habit of barking to go outside

Mendel's early work with pea plants demonstrated a significant genetic discovery. The crossing of homozygous tall pea plants with homozygous short pea plants always resulted in tall plants and demonstrated that tallness in pea plants is a trait that is —

• blended

• dominant

• mutated

• recessive

The physical expression of a genetic trait is called a

• mutation

• genotype

• crossing over

• phenotype

The following items are examples of __________.

Items: eye color, hair color, height

• homozygous alleles

• genotype

• heterozygous alleles

• phenotype

Start with the P generation with the following genotypes (AA x aa). Based on classical Mendelian inheritance, how will a cross between two homozygous parents, one dominant, one recessive, influence future generations?

• The F1 generation will show an even split between the dominant phenotypes and the recessive genotype.

• The F1 generation will show the dominant trait and future crosses will continue to produce genotypes expressing the dominant trait.

• Although the F1 generation will all show the dominant trait, the offspring will all be heterozygous and increase the chances of future variation.

• The F1 generation will show a mix of the dominant phenotype and recessive phenotype and over generations, the recessive trait will increase in number.

Using the chart shown, correctly identify how the genotype would be written for a heterozygous round seed shape.

• RR

• Rr

• rr

• rR

A couple has three brown-eyed children. The parents are brown-eyed (Bb). The allele for brown eyes is dominant over the allele for blue eyes. They believe the fourth child they have will be blue-eyed. Which statement below explains what actually will happen?

• The couple will have a blue-eyed fourth child.

• The couple will have a brown-eyed fourth child.

• They have a 75% chance of having a blue-eyed child.

• They have a 25% chance of having a blue-eyed child.

Chickens can have different types of feathers. Frizzled feathers curl toward a chicken’s head. Assume that feather type is determined by a single gene and that the allele for frizzled feathers is dominant over the allele for straight feathers. In a cross between two chickens with straight feathers, what percentage of the offspring can be expected to have frizzled feathers?

• 0%

• 25%

• 50%

• 100%

The four butterflies in the illustrations represent the offspring in the generation. Which statement is best supported by the phenotypes of these offspring?

• The F1 generation is composed only of males.

• Two of the offspring in the generation will not be able to reproduce.

• The generation is the result of a dihybrid cross.

• Two of the offspring in the generation will experience a spontaneous mutation.