Grade 11 University Biology – Unit 2 Genetics
Practice Test #2
1. You have a black-paw rabbit. You want to breed more black-paw rabbits to make your millions.
You do NOT know if your rabbit is homozygous or heterozygous. What genotype of rabbit would
you cross with your “unknown genotype” to determine its genotype?
Using Punnett squares, explain your answer. HINT: You will need to make two Punnett squares.
2. Compare INCOMPLETE DOMINANCE and CO-DOMINANCE. Give an example of each
3. The eye colour of cats is determined by three alleles: red (ER), green (EG) and yellow (EY). If red
is dominant over green, and green is dominant over yellow, what will the eye colours be is a
heterozygous green-eyed cat is crossed with a yellow-eyed cat?
4. Brothers Chuck and Andy learn genetics in Grade 11 Biology. Like their mother, they both have
red hair. Bart is also in the class. Bart teases Chuck and Andy that they are not the biological
sons of Ned (their father) because Ned has brown hair. Ned is the only one in the family that
does not have red hair. Chuck knows his genetics and responds Bart is wrong. How does Chuck
know that Ned is his biological father? Use a Punnett square to help Chuck prove his point.
5. The illustration is the Pedigree for red
hair.
Is the pedigree an illustration of
autosomal dominant inheritance,
autosomal recessive inheritance OR
X-linked inheritance? Provide one reason
with your answer.
Identify the genotype of the following
individuals:
 I2
 II3
 III5
6. A father is Type O blood and a mother is Type AB blood. What percentage of their children will
have Type O blood?
7. Charlene and Chad have a baby. Chad is heterozygous for both brown hair and brown eyes.
Charlene is also heterozygous for brown hair, but she has blue eyes (a recessive trait).
Using “H” for hair and “E” for eyes, what are the genotypes for the parents?
Use a Punnett Square to determine the possible phenotypes of their baby.
8. Is this illustration an example of Anaphase in mitosis,
Anaphase I in meiosis or Anaphase II in meiosis?
Explain your answer.
9. Why can recessive traits skip generations? Draw a simple PEDIGREE that contains three
generations to explain your answer.
10. Newt is colour blind (X-linked). He want to have a baby with a Mary who has colour vision but
she is a carrier of the colour blind trait.
What are the chances Newt and Mary will have a colour blind son?
What are the chances Newt and Mary will have a colour blind daughter?
ANSWERS
1. You have a black-paw rabbit. You want to breed more black-paw rabbits to make your millions.
You do NOT know if your rabbit is homozygous or heterozygous. What genotype of rabbit would
you cross with your “unknown genotype” to determine its genotype?
Homozygous recessive (white paw = rr)
Using Punnett squares, explain your answer. HINT: You will need to make two Punnett squares.
R
R
r
R
r
Rr
Rr
r
Rr
rr
r
Rr
Rr
r
Rr
rr
100% black-paw = homozygous dominant
50% black-paw = heterozygous dominant
You will want to breed the homozygous dominant to get 100% black-paws
2. Compare INCOMPLETE DOMINANCE and CO-DOMINANCE. Give an example of each
Incomplete Dominance – mixing of traits (e.g., red X white = pink)
Co-dominance – blend – both traits are expressed (e.g., red X white = 50% red and 50%
white)
3. The eye colour of cats is determined by three alleles: red (ER), green (EG) and yellow (EY). If red
is dominant over green, and green is dominant over yellow, what will the eye colours be is a
heterozygous green-eyed cat is crossed with a yellow-eyed cat?
The yellow-eyed cat must be homozygous EYEY so the yellow eye trait is expressed. For
the green eye trait to be expressed, the heterozygous genotype must be EGEY
EG
EY
EY
EREY
EYEY
EY
EGEY
EYEY
You get 50% green-eyed cats and 50% yellow-eyed cats
4. Brothers Chuck and Andy learn genetics in Grade 11 Biology. Like their mother, they both have
red hair. Bart is also in the class. Bart teases Chuck and Andy that they are not the biological
sons of Ned (their father) because Ned has brown hair. Ned is the only one in the family that
does not have red hair. Chuck knows his genetics and responds Bart is wrong. How does Chuck
know that Ned is his biological father? Use a Punnett square to help Chuck prove his point.
r
r
R
Rr
Rr
r
rr
rr
Ned is heterozygous dominant for brown hair. That means, Ned carries a recessive allele
for red hair. His genotype is Rr. Thus, his kids have a 50% chance of having red hair (rr).
5. The illustration is the Pedigree for red
hair.
Is the pedigree an illustration of
autosomal dominant inheritance,
autosomal recessive inheritance OR
X-linked inheritance? Provide one reason
with your answer.
Autosomal Recessive – skips a
generation
Identify the genotype of the following
individuals:
 I2
hh
 II3
Hh
 III5
HH or Hh
6. A father is Type O blood and a mother is Type AB blood. What percentage of their children will
have Type O blood?
IB
IA
i
IAi
IBi
i
IAi
IBi
No children will have Type O blood
7. Charlene and Chad have a baby. Chad is heterozygous for both brown hair and brown eyes.
Charlene is also heterozygous for brown hair, but she has blue eyes (a recessive trait).
Using “H” for hair and “E” for eyes, what are the genotypes for the parents?
Charlene
Hhee = He He he he
Chad
HhEe = HE He hE he
Use a Punnett Square to determine the possible phenotypes of their baby.
HE
He
hE
he
He
HHEe
HHee
HhEe
Hhee
He
HHEe
HHee
HhEe
Hhee
he
HeHe
Hhee
hhEe
hhee
he
HeHe
Hhee
hhEe
hhee
3/8 brown hair and brown eyes
3/8 brown hair and blue eyes
2/8 non-brown hair and blue eyes
8. Is this illustration an example of Anaphase in mitosis, Anaphase I in
meiosis or Anaphase II in meiosis? Explain your answer.
Anaphase I because the sister chromatids are still together but
the homogolous chromosomes are moving toward the poles of
the cell.
9. Why can recessive traits skip generations? Draw a simple PEDIGREE that contains three
generations to explain your answer.
The recessive trait only expresses if both recessive alleles are present. A heterozygous
parent can carry the recessive trait but not express it. If that parent crosses with another
heterozygous parent, a genotype will have two recessive alleles and the recessive trait is
expressed in the phenotype
10. Newt is colour blind (X-linked). He want to have a baby with a Mary who has colour vision but
she is a carrier of the colour blind trait.
What are the chances Newt and Mary will have a colour blind son?
What are the chances Newt and Mary will have a colour blind daughter?
Newt’s genotype is XCY
Mary’s genotype is XXC
X
XC
XC
XXC
XCXC
Y
XY
XCY
50% chance of colour blind boy
50% chance of colour blind girl