AP Biology
Saturday Study Session 2
Information Transfer
Student Packet
Session 4 – Mendelian Genetics
Multiple Choice Questions
1) In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of
red (RR) and white (rr) homozygous cattle. When two roan cattle are crossed, the phenotypes of
the offspring are found to be in the ratio of 1 red: 2 roan: 1 white. Which of the following crosses
could produce the highest percentage of roan cattle?
A)
B)
C)
D)
Red X White
Roan X Roan
White x Roan
Red X Roan
2) A couple who are both carriers of the gene for cystic fibrosis, a recessive genetic condition, have
two children who suffer from cystic fibrosis. What is the probability that their next child will be
phenotypically normal?
A)
B)
C)
D)
0%
25%
50%
75%
3) Tallness (T) is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The
heterozygous condition results in pink (Rr) flower color. A F1 dwarf, homozygous red snapdragon
is crossed with a F1 plant homozygous for tallness and also possesses white flowers. What are the
genotype and phenotype of the F2 individuals?
A)
B)
C)
D)
ttRr – dwarf and pink
TtRr – tall and pink
TtRr – tall and red
TTRR – tall and red
4) Feather color in budgies, a bird, is determined by two different genes that affect the pigmentation
of the outer feather and its core. Y_ B_ produces green feathers; yyB_ produces blue feathers; Y_bb
produces yellow feathers; yybb produces white feathers. The inheritance of color in budgies is an
example of what genetic phenomenon?
A)
B)
C)
D)
pleiotropy
penetrance
polygenic inheritance
epistasis
5) A man is brought to court in a paternity case. He has blood type B, Rh positive. The mother has
blood type B, Rh negative. The child’s blood type is AB, Rh negative. What can you say about the
man’s chances of being the father?
A)
B)
C)
D)
He is the father.
He might be the father.
He is not the father.
There is not enough information to make a conclusive decision.
6) Sickle cell anemia is the result of inheriting two alleles, each having a mutation in the DNA
sequence of the sixth amino acid for the primary sequence of the hemoglobin protein. This gene
has several phenotypic effects that will be seen in the individual. The ability of a single gene to
have multiple phenotypic effects is referred to as:
A)
B)
C)
D)
Multiple Alleles
Pleiotropy
Epistasis
Penetrance
Math Grid In
What is the probability that parents with the genotype of the father being Aa Bb Cc Dd and the mother
being Aa BB cc Dd producing an offspring whose genotype is Aa BB Cc dd? (Assume independent
assortment ao all gene pairs.)
Perform calculations here:
Short Free Response
1) The above pedigree shows the descendants of Queen Victoria. The chart shows those afflicted with
the genetic disease of hemophilia. State the source of the genetic disease, using the pedigree, and
explain the pattern displayed above as it relates to this disease. Explain how a female would
display hemophilia.
2) In a series of mapping experiments, the recombination/crossover frequencies for four different
linked genes of Drosophila were determined as shown below. The numbers in the boxes are the
recombination frequencies shown in percents. State the order of these genes on a chromosome
map. A drawing can help support your answer. Explain how you arrived at your conclusion.
b
cn
rb
vg
0
9.0
3.5
19.0
b
0
6.5
9.0
cn
0
16.0
rb
0
vg
Long Free Response