Mendel Quiz: Days 2-4; Law 2 and 3 _______________Name_________________ Period____


I would like to summarize Mendel's Laws by listing the cross that illustrates each.





TT x tt

tall x short

100% Tt



Tt x Tt

tall x tall

75% tall

25% short


RrGg x RrGg

round & green x round & green

9/16 round seeds & green pods

3/16 round seeds & yellow pods

3/16 wrinkled seeds & green pods

1/16 wrinkled seeds & yellow pods

There you have them, Mendel's huge contributions to the world of science.  A very smart cookie.  His work has stood the test of time, even as the discovery & understanding of chromosomes & genes has developed in the 140 years after he published his findings.  New discoveries have found "exceptions" to Mendel's basic laws, but none of Mendel's things have been proven to be flat-out wrong.

Hail to the "Father of Genetics" !

1. Which cross would best illustrate Mendel's Law of Segregation?

A. TT x tt

B. Hh x hh

C. Bb x Bb

D. rr x rr

2. In the cross Yy x Yy, what percent  of offspring would have the same phenotype as the parents?

A. 25%

B. 50%

C. 75%

D. 100%

3. In a certain plant, purple flowers are dominant to red flowers.  If the cross of two purple-flowered plants produces some some purple-flowered and some red-flowered plants, what is the genotype of the parent plants?

A. PP x Pp

B. Pp x Pp

C. pp x PP

D. pp x pp

Base questions #4-8 on the following information:

A white-flowered plant is crossed with a pink-flowered plant.  All of the F1 offspring from the cross are white.

4. Which phenotype is dominant? 

5. What are the genotypes of the original parent plants?


6. What is the genotype of all the F1 offspring? 

7. What would be the percentages of genotypes & phenotypes if one of the white F1 plants is crossed with a pink-flowered plant? 

8. Which of Mendel's Laws is/are illustrated in this question? 

9. Crossing two dihybrid organisms results in which phenotypic ratio?

A. 1:2:1

B. 9:3:3:1

C. 3:1

D. 1:1

10. The outward appearance (gene expression) of a trait in an organism is referred to as:

A. genotype

B. phenotype

C. an allele

D. independent assortment

11. In the homologous chromosomes shown in the diagram, which is a possible alleleic pair?

A. cD                         C. AB

B. Ee                         D. ee

12. The phenotype of a pea plant can best be determined by:

A. analyzing its genes

B. looking at it

C. crossing it with a recessive plant

D. eating it

13. Mendel formulated his Law of Segregation after he had:

A. studied F1 offspring

B. studied F2 offspring

C. produced mutations

D. produced hybrids

14. Which cross would produce phenotypic ratios that would illustrate the Law of Dominance?

A. TT x tt

B. TT x Tt

C. Tt x Tt

D. tt x tt

15. The mating of two curly-haired brown guinea pigs results in some offspring with brown curly hair, some with brown straight hair, some with white curly hair, and even some with white straight hair.  This mating illustrates which of Mendel's Laws?

A. Dominance

B. Segregation

C. Independent Assortment

D. Sex-Linkage