Mendelian Genetics

In pea plants, the trait for tall stems is dominant over the trait for short stems. If two heterozygous tall plants are crossed, what percentage of the offspring would be expected to have the same phenotype as the parents?

• 100%
• 75%
• 50%
• 25%

One of the parents of a child has phenylketonuria (PKU), which is caused by recessive alleles. The other parent does not have the PKU alleles. What is the chance that the couple will have a child with phenylketonuria?

• 0%
• 50%
• 75%
• 100%

The observable traits of an organism are known as its

• allele
• dominance
• phenotype
• genotype

Each parent contributes one of the genes for a particular trait. The genes of the pair are called:

• variables
• gametes
• hybrids
• alleles

In snapdragons, Tallness (T) is dominant to dwarfness (t). In a cross between two plants that are heterozygous for this trait, the percent of offspring expected to exhibit dwarfness is

•  25%
• 100%
• 50%
• 0%

The color black is dominant in guinea pigs. The phenotypes of homozygous black guinea pigs and heterozygous black guinea pigs are:

• black
• gray
• BB and Bb
• white

Passing on traits from parents to offspring

• Chromosome

• Genotype

• Heredity

• Allele

The study of heredity

• Genetics

• Genome

• Allele

• Punnett Square

The instruction of one allele covers up the instruction

of the other allele in a homologous pair. Symbolized by a capital letter.

• Recessive Allele

• Dominant Allele

• Heredity

• Trait

The instructions of this allele are covered up by the other allele in a homologous pair. Symbolized by a small letter.

• Homozygous

• Dominant

• Recessive

• Genetics