University of Tennessee

BIO 240

Quiz - 1 (Jan 18)

1)In a test cross, a pure-breeding plant is crossed with a plant suspected to be heterozygous (Aa). What is the genotype of the pure-breeding plant?

1. 1. Aa
   2. aa
   3. AA
   4. AA or Aa
   5. aa or Aa
2. Genetic crosses in which F₁ plants heterozygous for a given allele are crossed to generate a 3:1 phenotypic ratio in the F₂ generation are known as                                                              .
   1. monohybrid crosses
   2. dihybrid crosses
   3. replicate crosses
   4. test crosses
   5. reciprocal crosses
3. In peas, the smooth allele is dominant over the wrinkled allele. A plant with round peas was crossed to a plant with wrinkled peas and all of the resulting plants had smooth peas. What are the genotypes of the parents in this cross?
   1. Rr × Rr
   2. RR × rr
   3. rr × rr
   4. Rr × rr
   5. RR × Rr
4. You count 1000 F2 seeds from a monohybrid cross. How many do you expect to display the dominant phenotype?

a) 750

b) 0

c) 1000

d) 250

e)   500

5. Assuming independent assortment, what phenotypic ratio would you expect to see if an individual with the genotype RrGg is self-crossed?

a) 9:3:3:1

b) 1:3

c) 1:2:1

d) 1:3:2:1

e) 3:1

6. In peas, axial (A) flower position is dominant to terminal (a), tall (L) is dominant to short (l), and yellow (Y) is dominant to green (y). If a plant that is heterozygous for all three traits is allowed to self-fertilize, how many of the offspring would show the dominant phenotype for all three traits?

a)   32/64

b) 64/64

c)   27/64

d) 9/64

e)   3/64

7. The law of independent assortment predicts that crossing of dihybrid F₁ plants to one another would produce nine genotypes in a                                              ratio among the F₂progeny.

a) 9:3:3:1

b) 3:1

c)   1:2:1

d) 9:3:4

8. A couple has four children. What is the probability that they would have four boys?

a) 1/2

b) 1/16

c)   1/4

d) 1/8

e) 1/32

 

9. Which mode of inheritance for an allele on chromosome 15 does the pedigree suggest?

 

 

 

 

1. 1. X-linked recessive
   2. autosomal recessive
   3. autosomal dominant
   4. X-linked dominant

 

10. In mice, black coat color is dominant to white coat color. In the pedigree below, mice with a black coat are represented by darkened symbols, and those with white coats are shown as open symbols.

 

 

 

 

What is the genotype of III-1?

 

1. 1. heterozygous
   2. heterozygous or homozygous recessive
   3. homozygous recessive
   4. homozygous dominant
   5. homozygous dominant or heterozygous