Understanding Test Crosses

What is the purpose of a test cross?

• To measure the growth rate of plants

• To create new genetic variations

• To identify the genotype of an organism with a known phenotype

• To determine the phenotype of an organism

In the example of the tall pea plant, what are the possible genotypes?

• Homozygous dominant and homozygous recessive

• Homozygous dominant and heterozygous

• Heterozygous and homozygous recessive

• Homozygous recessive and heterozygous

Why is a dwarf pea plant used in the test cross?

• Because it produces more seeds

• Because it is more resistant to diseases

• Because it has a known genotype

• Because it is easier to grow

What is the genotype of the dwarf pea plant used in the test cross?

• Capital D lowercase D

• Lowercase d lowercase d

• Capital D lowercase d

• Capital D Capital D

In the Punnett square analysis, what is the expected phenotype ratio if the tall pea plant is heterozygous?

• 100% tall

• 50% tall, 50% dwarf

• 25% tall, 75% dwarf

• 75% tall, 25% dwarf

What does a 100% tall offspring result indicate about the genotype of the tall pea plant?

• It is a hybrid

• It is homozygous dominant

• It is heterozygous

• It is homozygous recessive

If the offspring are 50% tall and 50% dwarf, what is the genotype of the tall pea plant?

• Hybrid

• Homozygous recessive

• Heterozygous

• Homozygous dominant

What is the significance of using a homozygous recessive organism in a test cross?

• It reveals the genotype of the unknown organism

• It ensures all offspring are recessive

• It simplifies the genetic analysis

• It increases genetic diversity

What is the main character being tested in this example?

• Color

• Height

• Seed shape

• Flower position

What does the test cross help determine about the tall pea plant?

• Its growth rate

• Its genotype for height

• Its resistance to diseases

• Its phenotype