SBI3U Genetics Quiz 2
Mark: _____/26
Name: ________________
PART A – MULTIPLE CHOICE
Circle the answer that is the most correct. [8 marks]
1. Gregor Mendel used this organism to study genetics:
a. pig
b. fruit fly
c. pea plant
d. loch ness monster
2. In pea plants, purple flowers are dominant over white flowers. If a heterozygous purple pea
plant is mated with a homozygous purple pea plant, what are the possible offspring?
a. 50% white, 50% purple
b. all white
c. all purple
d. impossible to tell from this information
3. In cows, the polled trait (hornless) is dominant over the horned trait. A single bull mates with
three different cows and produces offspring, as shown in the figure below. What are the
genotypes of the bull, cow A, and cow B? (I)
a. bull – Pp; cow A – pp; cow B – Pp
b. bull – PP; cow A – pp; cow B – Pp
c. bull – Pp; cow A – pp; cow B – pp
d. bull – PP; cow A – Pp; cow B – Pp
bull
(polled)
cow A
(horned)
bull
(polled)
calf D
(horned)
cow B
(polled)
calf E
(horned)
bull
(polled)
cow C
(polled)
calf F
(polled)
4. If a flower’s height demonstrates incomplete dominance, and a tall flower is crossed with a
short flower, what would their offspring look like?
a. 50% tall, 50% short
b. 100% tall
c. 100% medium height
d. None of the above
5. If a disorder is autosomal dominant, the following is true:
a. A heterozygous person will not have the disorder
b. It will only be seen in body cells
c. It can skip generations
d. The problem gene is on a non-sex chromosome
6. If drooling is a dominant trait in a certain breed of dog, and two dogs which are heterozygous
for drooling breed, what is the probability that the puppies will drool?
a. 100%
b. 75%
c. 50%
d. 25%
7. A blue bird mates with a yellow bird and gives birth to a green offspring. This is an example
of:
a. Simple dominance
b. Co-dominance
c. Incomplete dominance
d. None of the above
8. In unicorns, the gene for hair colour exhibits co-dominance. If a homozygous blue haired
unicorn mates with a homozygous yellow unicorn, what hair colour would their children have?
a. 100% of offspring will have green hair
b. 100% of offspring will have blue hair
c. 100% of offspring will have yellow hair
d. 100% of offspring will have a mixture of blue and yellow hair
e. None of the above
Part C: Short Answers [18 marks]
1. Explain what Mendel’s experiment with peas showed and how it advanced our knowledge
about genetics. Be sure to list all the steps he took, and explain the significance of each step.
[3 marks]
2. Using your knowledge of polygenic inheritance, explain how two parents with dark skin could
have a child with light skin. [2 marks]
3. Explain what sickle cell anemia is and why there is a higher incidence rate of the disease in
Africa than in North America. [3 marks]
4. Use the following pedigree to answer the questions.
a. What type of inheritance does this pedigree likely show? Explain. [2 marks]
b. Does this show a vertical or horizontal pattern of inheritance? [1 mark]
c. Fill in the genotypes of each of the individuals on the pedigree. [2 marks]
2
1
7
4
8
3
5
9
6
5. Use the following pedigree to answer the questions.
a. What type of inheritance does this pedigree likely show? Explain. [2 marks]
b. Does this show a vertical or horizontal pattern of inheritance? [1 mark]
c. If Jack had 4 children, what proportion of his children would be expected to inherit the
trait? Draw a punnet square to show this. [2 marks]
BONUS QUESTION
1. In humans, haemophilia is a sex-linked recessive disorder (the problem gene is on the X
chromosome). If a man who has haemophilia marries a woman with no history of
haemophilia in her family, show (using a punnet square) that there is no possibility of
having a child with haemophilia. [2 marks]