Milestones in Biology 4: Test Your Knowledge

You have a tall pea plant.

a. What are its possible genotypes?

b. What crosses could you do to determine if it is true breeding or not? For each cross, give the expected phenotypes of the offspring.

In crossing pea plants:

a. If a true-breeding tall pea plant with purple flowers is crossed with another true-breeding tall pea plant with purple flowers, what will the offspring pea plants look like?

b. Will the offspring be true-breeding? Explain your answer.

Half of the gametes of a heterozygous parent will carry the dominant allele, and half will carry the recessive allele. Which of Mendel’s laws explains this?

Consider Mendel’s laws:

a. Which of Mendel’s laws would be violated if the offspring of two heterozygous tall, purple-flowered pea plants (denoted as TtPp) were only tall, purple-flowered plants or short, white-flowered plants?

b. What would such a violation suggest about the two genes?