Introduction to Genetics
Directions: Answer the following questions in complete
thoughts and on your own paper.
Section 11.1: The Work of Gregor Mendel
1. What is the study of heredity? Who is the modern founder?
2. What is a trait? Give some example traits of Mendel’s “true-breeding”
plants. What were the seven traits that Mendel studied on pea plants?
3. What is a hybrid? Give an example with pea plants.
4. How are genes and alleles related?
5. Explain the principle of dominance. Using Mendel’s seven crosses on pea
plants, state which trait is dominant and which is recessive (for all 7
traits.)
Section 11.2: Applying Mendel’s Principles
6. If you and your husband/wife have had eight boys, what is the
probability that your ninth child will be a girl? Explain your answer.
7. What does homozygous mean? What does heterozygous mean? Give an
example of each.
8. What is the difference between genotype and phenotype? If T=tall and
t=short, what is the phenotype of a Tt plant? What is the genotype of a
short plant?
9. You are studying the inheritance of dimples. D=dimples and d=no
dimples. If a heterozygous father is crossed with a homozygous recessive
mother, what is the probability that their child will have dimples? Use a
Punnett square to explain your answer.
10. Cross a pea plant that is heterozygous for a smooth, green pod (SsGg)
with a homozygous yellow, constricted pod (ssgg.) What are the
resulting phenotypes and their probabilities?
Section 11.3: Other Patterns of Inheritance
11. Using a Venn diagram, compare and contrast incomplete dominance
and codominance.
12. Describe multiple alleles and polygenic traits. How are they similar?
How are they different?
Section 11.4: Meiosis
13. Explain the difference between diploid and haploid cells. Give an
example of a diploid cell your body. Give an example of a haploid cell in
your body.
14. How many daughter cells are there at the end of meiosis I? Assuming
the parent cell had 18 chromosomes before meiosis began, how many
chromosomes does each daughter cell have at the end of meiosis I?
15. How many daughter cells are there at the end of meiosis II? Assuming
the parent cell had 18 chromosomes before meiosis began, how many
chromosomes does each daughter cell have at the end of meiosis II?