Practice Quiz for General Genetics
Chapter 3 -- Basic Principles of Heredity

Answers are at the bottom of the page. It would be best to answer all the questions before looking at the answers rather than simply memorizing the answers to these questions.

1. Which of the following is the most likely outcome of a cross between a heterozygous tall plant and a heterozygous tall plant?
A. 63 tall : 59 short
B. 76 tall : 23 short
C. 24 tall : 49 medium : 25 short
D. 53 tall : 147 short

2. Which of the following is a testcross?
B. AaBb X AaBb
C. AaBb x AABB
D. aabb X AaBb

3. In a cross between two black labrador retrievers the phenotypic ratio of the offspring is 9 black puppies to 3 chocolate puppies to 4 yellow puppies; this is an example of
A. partial recessiveness
B. incomplete penetrance
C. incomplete dominance
D. epistasis

4. In a cross between a black-skinned individual and a white-skinned individual the children will be intermediate in color (tan); this is an example of
A. partial recessiveness
B. incomplete penetrance
C. incomplete dominance
D. epistasis

5. Given an individual who is heterozygous at 5 loci, how many different gametic genotypes are possible?
A. 25
B. 10
C. 15
D. 32

6. Which of the following concepts is not attributable to Mendel?
A. one allele may be dominant to another allele at the same locus
B. chromosomes are the carriers of the genes
C. genetic traits are particulate in nature
D. the pair of alleles at a locus separate from each other during gamete formation

7. When studying an inherited phenomenon, a geneticist discovers a phenotypic ratio of 9:3:3:1 among offspring of a given mating. A possible explanation for this is a two locus-two alleles at each locus system that exhibits
A. epistasis
B. linkage
C. pleiotropy
D. independent assortment

8. Given complete dominance among the pairs of alleles at each of four loci, a cross between two tetrahybrids will produce how many different phenotypes among the offspring?
A. 8
B. 10
C. 16
D. 32
E. 64

9. At a single locus, there are 4 alleles segregating in the population. How many different genotypes can possibly occur at this single locus in the population?
A. 8
B. 10
C. 16
D. 32
e. 64

10. The wildtype phenotype refers to
A. the phenotype expressed by the dominant allele
B. the phenotype expressed by the recessive allele
C. the phenotype that most commonly ocurrs in nature
D. the phenotype that has the longest survival

11. In peas, a tall, yellow-seeded plant is crossed with a homozygous short, green-seeded plant and yields 203 tall, green-seeded plants, 199 short, green-seeded plants, 207 tall, yellow-seeded plants, and 192 short, yellow-seeded plants. The most likely genotype of the tall, yellow-seeded parent is
A. TtYy
C. ttyy
D. ttYY

12.A monohybrid cross tests which of the following rules?
A. Rule of Independent Assortment
B. Chromosome Theory of Inheritance
C. Rule of Segregation
D. Cell Theory of Gametes

13. Relative to a cross between a black-bodied male and a wildtype female fruit fly, the cross between a wildtype male and a black-bodied female is called the
A. testcross
B. reciprocal cross
C. pleiotropic cross
D. sex cross

14. In a species of plant, a cross between a homozygous purple-flowered plant and a homozygous white-flowered plant yields all lavender-flowered plants. The purple allele is
A. dominant
B. recessive
C. pleiotropic
D. incompletely dominant

15. In tomatoes, there are two alleles that affect stem color, one purple (P) and one green (p). The following crosses are performed with these results
 parental phenotype                  offspring  phenotypes
1. purple x green 422 purple, 417 green
2. purple x purple 426 purple, 135 green
3. purple x green 953 purple, 0 green
4. purple x green 404 purple, 387 green
What is the phenotype of the purple parent in cross number 4?
B. Pp
C. pp
D. pp

1.B; 2.D; 3.D; 4.C; 5.D; 6.B; 7.D; 8.C; 9.B; 10.C; 11.A; 12.C; 13.B; 14.D; 15.B

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