Name: _______________________________
Score: _____/20
Self Assessment: Ch 11, so far
The hornless condition (H) in cattle is dominant to horned (h). A hornless bull was
mated to a hornless cow. The offspring was born with horns.
1. What are the parents genotypes ____________ x____________
2. Show the Punnett Square
3. List all possible genotypes and percentages (genotypic ratio)
4. List all possible phenotypes and percentages (phenotypic ratio)
5. What type of inheritance is this?______________________
A pure-bred red bull (R) is mated with a pure-bred white cow (r) and produce
offspring that is both red and white (Rr) or roan. What would the offspring look
like if two roan mated?
6. What are the parents Genotypes ____________ x____________
7. Show the Punnett Square
8. List all possible genotypes and percentages (genotypic ratio)
9. List all possible phenotypes and percentages (phenotypic ratio)
10. What type of inheritance is this?______________________
SpongeBob loves growing flowers for his pal Sandy! Her favorite flowers, Poofkins,
are found in red (R), blue(r), and purple (Rr).What would happen if SpongeBob
crossed a Poofkin with red flowers with one with blue flowers?
11. What are the parents Genotypes ____________ x____________
12. Show the Punnett Square
13. List all possible genotypes and percentages (genotypic ratio)
14. List all possible phenotypes and percentages (phenotypic ratio)
5. What type of inheritance is this?______________________
In pea plants, flowers in the middle (axial, A) is dominant to
flowers at the ends of stems (terminal, a). Use this
information to answer the following.
16. – 17. Can I tell the difference between a pure bred plant
with axial flowers and a hybrid plant with axial
flowers? Explain why/why not, in detail.
18. – 19. Two plants with axial flowers are crossed. The results are 412 plants with
axial flowers and 408 plants with terminal flowers. What are the original
genotypes of the parents? Explain how you know this.
20. If I have a plant with axial flowers, how can I determine whether it is pure bred or
a hybrid?
Answer Key__
Name: __
Score: _____/20
Self Assessment: Ch 11, so far
The hornless condition (H) in cattle is dominant to horned (h). A hornless bull was
mated to a hornless cow. The offspring was born with horns.
Hh_ x__ Hh __
1. What are the parents genotypes _
2. Show the Punnett Square
H h
H HH Hh
h Hh hh
3. List all possible genotypes and percentages (genotypic ratio)
HH
25%
Hh
50%
hh
25%
4. List all possible phenotypes and percentages (phenotypic ratio)
hornless
75%
horned
25%
simple dominance__
5. What type of inheritance is this? _
A pure-bred red bull (R) is mated with a pure-bred white cow (r) and produce
offspring that is both red and white (Rr) or roan. What would the offspring look
like if two roan mated?
6. What are the parents Genotypes __
7. Show the Punnett Square
Rr__ x__Rr__
R r
R RR Rr
r Rr rr
8. List all possible genotypes and percentages (genotypic ratio)
RR
25%
Rr
50%
rr
25%
9. List all possible phenotypes and percentages (phenotypic ratio)
red
25%
roan
50%
10. What type of inheritance is this?__
white
25%
codominance_
SpongeBob loves growing flowers for his pal Sandy! Her favorite flowers, Poofkins,
are found in red (R), blue(r), and purple (Rr).What would happen if SpongeBob
crossed a Poofkin with red flowers with one with blue flowers?
11. What are the parents Genotypes _
12. Show the Punnett Square
r
r
R
Rr
Rr
RR_ x__rr__
R
Rr
Rr
13. List all possible genotypes and percentages (genotypic ratio)
RR
0%
Rr
100%
rr
0%
14. List all possible phenotypes and percentages (phenotypic ratio)
red
0%
purple
100%
15. What type of inheritance is this?_
blue
0%
incomplete dominance_
In pea plants, flowers in the middle (axial, A) is dominant to
flowers at the ends of stems (terminal, a). Use this
information to answer the following.
16. – 17. Can I tell the difference between a pure bred plant
with axial flowers and a hybrid plant with axial
flowers? Explain why/why not, in detail.
No, they look exactly the same.
When the plant makes the protein that controls
“flower position” the axial allele is dominant
and is the one copied into mRNA (…). The
terminal allele is not copied at all, so it is not
like the plant is “just a little shorter.”
18. – 19. Two plants with axial flowers are crossed. The results are 412 plants with
axial flowers and 408 plants with terminal flowers. What are the original
genotypes of the parents? Explain how you know this.
Aa x aa
Because the recessive trait is present, each
parent must have at least one recessive allele
(both must be _a, but could be Aa or aa). That
leaves 3 possibilities: Aa x Aa, aa x aa or Aa x
aa. (AA is not a possibility, because there would
be no terminal plants, then.)
If the parents were both Aa, you’d get a 3:1
phenotypic ratio.
If the parents are both aa, you’d get 100%
terminal flowers.
If the parents were Aa and aa, you’d get a 50%
ratio. 
20. If I have a plant with axial flowers, how can I determine whether it is pure bred or
a hybrid?
Cross it with something that is known (usually
a purebred recessive) and look at the results.
Let’s say we know a plant is purebred terminal,
aa…there are two possibilities for our unknown:
AA and Aa.
If our unknown is AA, we will have this cross:
AA x aa and all the new plants will have axial
flowers (and be hybrids).
If our unknown is Aa, we will have this cross:
Aa x aa and ½ the plants will have axial flowers
(Aa) and ½ will have terminal flowers (aa).
This process is called a test cross.
4. Poofkins come with even numbered (E) or odd numbered (e) of flowers per plant.
What would happen if SpongeBob crossed a Poofkin with an odd number of red
flowers with one with with an even number (heterozygous) of purple flowers?
a. What are the parents Genotypes ____________ x____________
b. Show the Punnett Square
c. List all possible genotypes and
percentages (genotypic ratio)
d. List all possible phenotypes and
percentages (phenotypic ratio)
4. Poofkins come with even numbered (E) or odd numbered (e) of flowers per plant.
What would happen if SpongeBob crossed a Poofkin with an odd number of red
flowers with one with with an even number (heterozygous) of purple flowers?
a. What are the parents Genotypes _
b. Show the Punnett Square
c. List all possible genotypes and
percentages (genotypic ratio)
25%
25%
25%
25%
EeRR
EeRr
eeRR
eeRr
eeRR_ x _EeRr_
eR
ER
EeRR
Er
EeRr
eR
eeRR
er
eeRr
d. List all possible phenotypes and
percentages (phenotypic ratio)
25%
25%
25%
25%
even #, red
even #, purple
odd #, red
odd #, purple