University of Tennessee

BIO 240

Quiz 2 (Feb 1)

Q1)Crossing white-eyed male Drosophila to red-eyed females produces all red-eyed

F₁ offspring, but the one half of the males in the F₂ generation are white-eyed. What concept best explains this observation of eye color?

1. 1. 1. autosomal dominance
      2. random mutation
      3. X-linked inheritance
      4. independent assortment
      5. crossing over

Q2.      Chromosomal nondisjunction of the X chromosome in female gametes of humans means that live offspring can include                                                    .

1. females with XX or XO, and males with XY or OY
2. females with XX, and males with XY
3. females with XX or XXX, and males with XY or XO
4. females with XX or XXX, and males with XY or XXY
5. females with XX, and males with XY or XO

Q3.      The biological sex of birds and some other mammals can be explained by females containing                                               chromosomes and males containing                              chromosomes. (AMBIGUOUS)

1. X; Y
2. Z; W
3. ZW; ZZ
4. XY; XX
5. XX; XY

Q4.      What type of molecule is the gene product of the SRY gene in mammals?

1. A transcription factor protein
2. A regulatory RNA
3. A hormone
4. A hormone receptor

Q5.      If a trait is X-linked recessive, who would express the trait?

1. the same proportions of females and males
2. heterozygous females and males hemizygous for the dominant allele
3. females homozygous for the recessive allele and males hemizygous for the dominant allele
4. females homozygous for the recessive allele and males hemizygous for the recessive allele
5. females homozygous for the dominant allele and males hemizygous for the recessive allele

Q6.      Red-green color blindness is an X-linked recessive disorder. A woman with normal vision whose father was colorblind has children with a man with normal color vision. What is the probability that their first child will be colorblind?

a) 1/2

b) 0

c) 1/4

d) 3/4