BIO II: Mendelian/Human Genetics Test Review Sheet
1. A couple who are both carriers for the Cystic Fibrosis gene have two children
who have the disease. What is the probability that their next child will also
have the disease? What is the probability that the child will be phenotypically
normal? (CF is autosomal recessive)
2. What is Pleiotropy? Give an example of a disease which fits this description.
3. What type of cell would you typically be able to find a Barr Body in?
4. What is a test-cross? Why is it used?
5. Give an example of polygenic inheritance.
6. Explain Mendel’s Law of Independent Assortment. How was this observed
in Mendel's experiment with pea plants? Was each of the seven traits
followed by Mendel determined to be on the same or different
chromosomes? (circle one)
7. The closer the genes are on the chromosome, the ________________ the
likelihood of crossing over. Therefore the frequency of crossing over between
any two linked genes is proportional to the____________ between them.
8. What is a Locus?
9. Describe each of the following modes of inheritance:
10. What is gene linkage? Give an example.
11. What is an allele? Give an example of an allele using Mendel's experiments
with the pea plants and the traits that he followed.
12. In roses, heterozygotes have pink flowers while homozygotes have either red
or white flowers. When plants with red flowers are crossed with plants with
white flowers , what proportion of the offspring will have pink flowers?
13. A woman and her husband both show the normal phenotype for pigmentation,
but both had one parent who was albino. Albinism is an autosomal recessive
What is the probability that their first child will be an albino?
What is the probability that their third child will be an albino?
What is the chance that their fourth child will be homozygous dominant?
14. In cattle, roan coat color (mixed red and white hairs) occurs in the
heterozygous (Rr). (RR) individuals are red, (rr) individuals are white. What
cross would produce the largest percentage of roan cattle?
15. Answer the following questions based on the following pedigree.
The following pedigree shows the inheritance of red-green colorblindness.
What is the genotype of individual #10?
What is the phenotype of individual #10?
What is the genotype of individual # 7?
What is the phenotype of individual #7?
What is the genotype of individual #15?
What is the phenotype of individual #15?
16. Know how to solve a paternity case using blood typing inheritance!!! Ex. John
is blood type B, Martha is blood type AB. What is the chance that their child
will have blood type O? Blood type A? Blood type AB? Blood type B?
How many copies of each chromosome are found in every somatic cell in
Pairs of alleles separate during the formation of gametes during which
stage (division) of Meiosis?
The law of Independent Assortment does not apply to
Crossing over disrupts normal __________________ _________________.
The ABO blood groups, discovered by Dr. Karl Landsteiner, are based on
the presence or absence of specific _______________ on the surface of red
Give at least 3 current techniques used in screening for genetic disorders.
This is a question that will separate the “A” Bio II students from the
rest of the pack! Four genes: J, K, L, and M reside on the same
chromosome. Given that the crossover frequency between K and J is 3,
between K and L is 8, between J and M is 12, and between L and M is 7, what
is the order of the genes on the chromosome? I would suggest making a
There will also be some Punnett Square problems on this test. Be able to
solve problems like the following types.
In, snapdragons, the allele for tall plants (T) is dominant to the allele for
dwarf plants (t), and the allele for red flowers (R) is codominant with the allele
for white flowers (r) . The heterozygous condition for flower color is pink (Rr).
If a dwarf red snapdragon is crossed with a white snapdragon homozygous for
tall, what are the probable genotypes and phenotypes of the F1 generation?
If ttRr is crossed with TtRR, what would be the probable frequency for
offspring that are dwarf and white?
24. A woman and her husband both show the normal phenotype for
pigmentation, but both had one parent who was an albino, Albinism is an
autosomal recessive trait.
● What is the probability that their first child will be an albino?
● If their first two children have normal pigmentation, what is the chance that
their third child will be an albino?
● What is the chance that their fourth child will have a homozygous genotype?
Some people are able to roll their tongues into a U-shape. The ability to
do this is inherited as an autosomal dominant allele. What is the probability
that children descendent from parents both heterozygous for this trait will be
able to form a U-shape with their tongues?
In fruit flies, dumpy wings are shorter and broader than normal wings. The
allele for normal wings (D) is dominant to the allele for dumpy wings (d). Two
normal winged flies were mated and produced 300 normal winged and 100
dumpy winged flies. What genotypes did the parents probably have?
Suppose a person has the genotype Dd. What is true of the gametes
produced by an individual with this genotype? What percentage chance is
there of the parent giving the D vs. d to their offspring?
Suppose that in sheep, a dominant allele (B) produces black hair and a
recessive allele (b) produces white hair. If you saw a black sheep, you would
be able to identify for certain its __________________________.
Red-headed people frequently have freckles. What is the best
explanation for this?
Let A and a represent two alleles for one gene and B and b represent two
alleles for a second gene. If for a particular individual, A and B were on one
chromosome and a and b were on a second chromosome, answer the
Are the two genes linked?
Are the two chromosomes homologous?
What is the genotype of this individual?
Could an offspring of this individual have the genotype AABB?
A human genetic defect that is caused by nondisjunction of the sex
chromosomes is: __________________________. A disorder caused by
non-disjunction of the autosomes would be: __________________________.
What is Aneuploidy?
Give an example of a sex-limited trait seen in animals.
From which parent(s) did a male with red-green colorblindness inherit the
35. In snapdragons, heterozygotes have pink flowers, whereas homozygotes
have either red or white flowers. When plants with red flowers are crossed with
plants having white flowers, what proportion of the offspring will have pink