Name:
Directions: Answer the following questions in order to help you prepare for your genetics test.
The test will be in the same format as previous tests with 50 multiple choice, fill in the blank,
and short answer questions.
1. Match the following vocabulary words to their definitions:
B. Genotype
_____ 1. The genetic makeup (genes) of an organism. An
example would be : Tt
_____ 2. A cross showing two traits.
C. Pure or True -breed
_____ 3. The trait that would be masked in the heterozygous.
D. Hybrid
G. Recessive
_____ 4. Another way to say that an organism is heterozygous for
a trait.
_____ 5. Possessing one of each allele (two different alleles) for a
trait.
_____ 6. The physical representation (what you can see) of a trait.
An example would be blue eyes.
_____ 7. A cross showing only one trait.
H. Dominant
_____ 8. Possessing two of the same alleles for a trait.
I. Monohybrid
_____ 9. Another word for an organism that is homozygous for a
trait.
_____ 10. The trait that is expressed in both homozygous and
heterozygous forms if it is present.
A. Phenotype
E. Homozygous
F. Heterozygous
J. Dihybrid
2. Who was Gregor Mendel? _____________________________________________
a. What organism did Mendel spend 7 years studying? ___________________
b. What name do we now give to Mendel’s “factors”? _____________________
3. What is the purpose of a Punnett square?
4. Define probability.
a. If I flip a coin 9 times, and it comes up heads every time – what is the probability that it
will come up heads on the 10th try? _______
5. Define Mendel’s three principles:
a. Law of Independent Assortment:
b. Law of Segregation:
c. Principle of Dominance:
6. Mendel was able to control a lot of his experiments by allowing some peas to crosspollinate, while some plants he self-pollinated. What is the difference between cross and
self-pollination?
7. In a Dihybrid cross, what are the allele combinations that would be found in the gametes
produced by a pea plant whose genotype is PpTt? _____________________________
8. If a homozygous pea plant for purple flowers and tall (PPTT), is crossed with a
homozygous recessive plant (pptt), how many phenotypes can you expect to see?
____________________
9. Compare and contrast mitosis to meiosis.
Mitosis
Meiosis
# of divisions
# of cells produced
# of chromosomes
(haploid/diploid?)
Purpose (asexual or
sexual reproduction?)
Cells produced are
identical or different?
10. . A human has 23 pairs of chromosomes. What is our diploid number? _______
a. What is our haploid number? ________
b. What would our skin cells be? (diploid/haploid)
c. What would our gametes be? (diploid/haploid)
11. Describe crossing over. When in meiosis would this occur?
12. What is the purpose of meiosis? During which step do the cells go from diploid to
haploid?
13. In the above dihybrid cross identify the genotype and phenotype of the offspring that
would be represented in the square labeled X.
a. What are the genotypes of the offspring that have brown, almond eyes?
b. Write a fraction of the offspring that would be expected to have blue, round eyes.
c. In the above dihybrid cross, what are the different phenotypes of the offspring?
14. Complete the following practice Punnett squares and list the possible genotypes and
phenotypes:
a. TT with Tt
b. TT with tt
15. Define incomplete dominance. Give an example.
16. Define sex-linked trait. Give an example.
a. Most sex-linked genes are located on which sex chromosome?
17. Define codominance. Give an example.
18. Is it possible for a man with type A blood and a woman with type B blood to have
children with type O blood? Explain.