Download Practice Quiz for General Genetics

Biology: Practice Quiz for General Genetics
Mendel's Principles
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?
A. AABB x AABB
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-haired rabbit and a white-haired rabbit the offspring 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
10. 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
B. TTYY
C. ttyy
D. ttYY
11. 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
12. In a species of plant, a cross between a homozygous purple-flowered plant and a homozygous whiteflowered plant yields all lavender-flowered plants. The purple allele is
A. dominant
B. recessive
C. pleiotropic
D. incompletely dominant
13 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
1. P x G
2. P x P
3. P x G
4. P x G
offspring phenotypes
422 purple, 417 green
426 purple, 135 green
953 purple, 0 green
404 purple, 387 green
What is the phenotype of the purple parent in cross number 4?
A. PP
B. Pp
C. pp
D. pg
Genetics Problems
14. A brown mouse is mated with a white mouse. All of their offspring are brown. If two of these brown
offspring are mated, what fraction of their offspring will be white?
15. Suppose you wanted to know the genotype of one of the brown F2 mice in question 14. The easiest
way to do it would be to do it would be to do what?
16. Some dogs bark while trailing; others are silent. The barker gene is dominant, the silent gene
recessive. The gene for normal tail is dominant over the gene for curly tail. A barker dog with a
normal tail who is heterozygous for both characteristics is mated to another dog of the same genotype.
What fraction of their offspring will be barkers with curly tails?
17. A young unmarried woman had a baby and wished to collect child support from the father. Her blood
group is AB. The baby’s blood group is A. There are two possible fathers: Jim is group A, and
Michael is group O. Which man could be the father?
18. When two gray-bodied fruit flies are mated, their offspring total 86 gray-bodied males, 81 yellow
bodied males, and 165 gray-bodied females. The allele for yellow body is
a. sex-linked and dominant
b. not sex-linked and dominant
c. sex-linked and recessive
d. not sex-linked and recessive
e. impossible to say on the basis of this data
19. Red-green color blindness is a human recessive sex-linked trait. A man and a woman with normal
vision have a color-blind son. What is the probability that their next child will also be a color-blind
son?
20. Duchenne muscular dystrophy is caused by a sex-linked recessive allele. Its victims are almost
invariably boys, who usually die before the age of 20. Why is this disorder almost never seen in girls?