TCSS Biology Sample Assessment Items
Unit 2 – Concept 4 Mendelian Genetics
SB2C. Using Mendel’s laws, explain the role of meiosis in reproductive variability.
1.
Which statement describes the offspring that would result if individual 1 has children
with a woman that does not carry the allele for this disorder?
a.
b.
c.
d.
None of the daughters will inherit the allele for the disorder.
All of the sons will inherit the allele for the disorder.
All of the daughters will be affected by the disorder.
None of the sons will be affected by the disorder.
2. Round seeds (R) are the dominant seed shape for pea plants; wrinkled (r) is the recessive
seed shape for pea plants. A pea plant with round seeds is crossed with a pea plant with
wrinkled seeds and all the offspring have round seeds.
What are the genotypes of the two parent plants in this cross?
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3. What is the expected phenotypic ratio of seed shape in offspring if a heterozygous plant
is crossed with a homozygous recessive plant?
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4. A genetic cross was made between pure-breeding snapdragon plants with red flowers and
pure-breeding snapdragon plants with white flowers. The cross produced F1 offspring
that had only pink flowers. When the F1 plants were self-pollinated, the resulting F2
generation had some red, some white and some pink flowers.
(i)
Identify the relationship between the red and white alleles for flower color.
(ii)
Deduce the genotype of the F1 plants.
(iii)
Construct a Punnett grid to show the cross between two F1 plants.
(iv)
Deduce the proportion of the different phenotypes of the F2 offspring.
5. A genetic cross was made between pure-breeding snapdragon plants with red
flowers and pure-breeding snapdragon plants with white flowers. The cross
produced F1 offspring that had only pink flowers. When the F1 plants were selfpollinated, the resulting F2 generation had some red, some white and some pink
flowers.
(i)
Identify the relationship between the red and white alleles for flower color.
(ii)
Deduce the genotype of the F1 plants.
(iii)
Construct a Punnett grid to show the cross between two F1 plants.
(iv)
Deduce the proportion of the different phenotypes of the F2 offspring.
6. Which set of parents can most likely produce a child with type O blood?
a. one parent with type AB blood, and the other parent with type A blood
b. one parent with type AB blood, and the other parent with type O blood
c. one parent with heterozygous type A blood, and the other parent with type O
blood
d. one parent with homozygous type A blood, and the other parent with
homozygous type B blood