Name: 
 

Genetics Practice Test


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
Mendel prevented self-pollination of his plants by
a.
growing only one kind of plant.
b.
 preventing crossing-over.
c.
 removing the anthers of the plants.
d.
removing the stigmas of the plants.
 

 2. 
The “father” of genetics was
a.
T. A. Knight.
c.
Gregor Mendel.
b.
 Hans Krebs.
d.
 None of the above
 

 3. 
Mendel obtained his P generation by allowing the plants to
a.
self-pollinate.
c.
assort independently.
b.
cross-pollinate.
d.
segregate.
 

 4. 
What is the probability that the offspring of a homozygous dominant individual and a homozygous recessive individual will exhibit the dominant phenotype?
a.
0.25
c.
0.66
b.
 0.5
d.
 1.0
 

 5. 
True-breeding pea plants always
a.
are pollinated by hand.
b.
 produce offspring each of which can have multiple forms of a trait.
c.
 produce offspring each of which can have only one form of a trait.
d.
 are heterozygous.
 

 6. 
The first filial (F1) generation is the result of
a.
cross-pollination among parents and the next generation.
b.
 crosses between individuals of the parental generation.
c.
 crosses between the offspring of a parental cross.
d.
self-fertilization between parental stock.
 

 7. 
Which of the following is the designation for Mendel’s original pure strains of plants?
a.
P
c.
F1
b.
 P1
d.
 F2
 

 8. 
F2 : F1 ::
a.
P : F1
c.
F1 : P
b.
 F1 : F2
d.
 dominant trait : recessive trait
 

 9. 
The passing of traits from parents to offspring is called
a.
genetics.
c.
development.
b.
 heredity.
d.
 maturation.
 

 10. 
A genetic trait that appears in every generation of offspring is called
a.
dominant.
c.
recessive.
b.
 phenotypic.
d.
 superior.
 

 11. 
homozygous : heterozygous ::
a.
heterozygous : Bb
c.
BB : Bb
b.
 probability : predicting chances
d.
 homozygous : BB
 

 12. 
Mendel’s finding that the inheritance of one trait had no effect on the inheritance of another became known as the
a.
law of dominance.
b.
 law of universal inheritance.
c.
law of separate convenience.
d.
 law of independent assortment.
 

 13. 
To describe how traits can disappear and reappear in a certain pattern from generation to generation, Mendel proposed
a.
the law of independent assortment.
b.
 the law of segregation.
c.
 the law of genotypes.
d.
that the F2 generation will produce only purple flowers.
 

 14. 
The law of segregation explains that
a.
alleles of a gene separate from each other during meiosis.
b.
 different alleles of a gene can never be found in the same organism.
c.
 each gene of an organism ends up in a different gamete.
d.
each gene is found on a different molecule of DNA.
 

 15. 
When Mendel crossed pea plants that differed in two characteristics, such as flower color and plant height,
a.
these experiments led to his law of segregation.
b.
 he found that the inheritance of one trait did not influence the inheritance of the other trait.
c.
 he found that the inheritance of one trait influenced the inheritance of the other trait.
d.
 these experiments were considered failures because the importance of his work was not recognized.
 

 16. 
The phenotype of an organism
a.
represents its genetic composition.
b.
 reflects all the traits that are actually expressed.
c.
occurs only in dominant pure organisms.
d.
 cannot be seen.
 

 17. 
If an individual has two recessive alleles for the same trait, the individual is said to be
a.
homozygous for the trait.
b.
 haploid for the trait.
c.
 heterozygous for the trait.
d.
mutated.
 

 18. 
An individual heterozygous for a trait and an individual homozygous recessive for the trait are crossed and produce many offspring. These offspring are likely to be
a.
all the same genotype.
b.
 of two different phenotypes.
c.
of three different phenotypes.
d.
 all the same phenotype.
 

 19. 
Tallness (T) is dominant over shortness (t) in pea plants. Which of the following represents the genotype of a pea plant that is heterozygous for tallness?
a.
T
c.
Tt
b.
 TT
d.
 tt
 
 
In humans, having freckles (F) is dominant over not having freckles (f). The inheritance of these traits can be studied using a Punnett square similar to the one shown below.

nar001-1.jpg
 

 20. 
Refer to the illustration above. The genotype represented in box 1 in the Punnett square would
a.
be homozygous for freckles.
b.
 have an extra freckles chromosome.
c.
be heterozygous for freckles.
d.
 have freckles chromosomes.
 

 21. 
Refer to the illustration above. The genotype in box 3 of the Punnett square is
a.
FF.
c.
ff.
b.
 Ff.
d.
 None of the above
 

 22. 
A trait that occurs in 450 individuals out of a total of 1,800 individuals occurs with a probability of
a.
0.04.
c.
0.50.
b.
 0.25.
d.
 0.75.
 

 23. 
How many different phenotypes can be produced by a pair of codominant alleles?
a.
1
c.
3
b.
 2
d.
 4
 
 
nar002-1.jpg
 

 24. 
Refer to the illustration above. The phenotype represented by box 1 is
a.
green, inflated.
c.
yellow, inflated.
b.
 green, constricted.
d.
 yellow, constricted.
 

 25. 
Refer to the illustration above. The genotype represented by box 2 is
a.
GgIi.
c.
GI.
b.
 GGIi.
d.
 Gi.
 

 26. 
2,000 yellow seeds : 8,000 total seeds ::
a.
1 : 6
c.
1 : 3
b.
 1 : 8
d.
 1 : 4
 
 
In rabbits, black fur (B) is dominant over brown fur (b). Consider the following cross between two rabbits.

nar003-1.jpg
 

 27. 
Refer to the illustration above. The device shown, which is used to determine the probable outcome of genetic crosses, is called a
a.
Mendelian box.
c.
genetic graph.
b.
 Punnett square.
d.
 phenotypic paradox.
 

 28. 
Refer to the illustration above. Both of the parents in the cross are
a.
black.
b.
 brown.
c.
 homozygous dominant.
d.
homozygous recessive.
 

 29. 
Refer to the illustration above. The phenotype of the offspring indicated by box 3 would be
a.
brown.
b.
 black.
c.
 a mixture of brown and black.
d.
The phenotype cannot be determined.
 

 30. 
Refer to the illustration above. The genotypic ratio of the F1 generation would be
a.
1:1.
c.
1:3.
b.
 3:1.
d.
 1:2:1.
 

 31. 
What is the expected genotypic ratio resulting from a homozygous dominant ´ heterozygous monohybrid cross?
a.
1:0
c.
1:2:1
b.
 1:1
d.
 1:3:1
 

 32. 
What fraction of the offspring resulting from a heterozygous ´ heterozygous dihybrid cross are homozygous recessive for both traits?
a.
9/16
c.
3/16
b.
 1/4
d.
 1/16
 

 33. 
What is the expected genotypic ratio resulting from a heterozygous ´ heterozygous monohybrid cross?
a.
1:2:1
c.
1:2
b.
 1:3:1
d.
 1:0
 

 34. 
What is the expected phenotypic ratio resulting from a homozygous dominant ´ heterozygous monohybrid cross?
a.
1:3:1