BIOD210 GENETICS | PORTAGE LEARNING | COMPLETE
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BIOD210 Exam 1: Mendelian Foundations
1. In a monohybrid cross between two heterozygous tall pea plants (Tt × Tt), what is
the expected phenotypic ratio in the F₁ generation?
A. 1:2:1
B. 3:1
C. 1:1
D. 2:1
Correct Answer: B
Rationale: 3 tall : 1 short. Genotypic ratio is 1 TT : 2 Tt : 1 tt, but phenotype shows
complete dominance.
2. A test-cross is performed to determine the genotype of a tall pea plant. If the
unknown plant is homozygous (TT), what will be the phenotypic ratio of its
offspring when crossed with a homozygous recessive (tt)?
A. All tall
B. 1 tall : 1 short
C. 3 tall : 1 short
D. All short
Correct Answer: A
Rationale: TT × tt → all Tt (tall). A 1:1 ratio would indicate the unknown was
heterozygous.
, 3. In humans, brown eyes (B) are dominant over blue (b). A brown-eyed man and a
blue-eyed woman produce a blue-eyed child. What is the man’s genotype?
A. BB
B. Bb
C. bb
D. Cannot be determined
Correct Answer: B
Rationale: Child is bb → must receive b from each parent. Man must be Bb (carrier).
4. Which of the following best describes Mendel’s Law of Independent Assortment?
A. Alleles separate during gamete formation
B. Genes on the same chromosome assort together
C. Genes for different traits segregate independently if on different
chromosomes
D. Dominant alleles always mask recessive ones
Correct Answer: C
Rationale: Independent assortment applies to genes on different chromosomes (or far
apart on the same chromosome).
5. In a dihybrid cross (AaBb × AaBb), how many different gamete genotypes can
each parent produce?
A. 2
B. 4
C. 6
D. 8
Correct Answer: B
Rationale: 2ⁿ where n = number of heterozygous gene pairs; here n = 2 → 4 gamete
types (AB, Ab, aB, ab).
6. What is the probability of obtaining an AaBb individual from a cross between
AaBb and AABB?
A. 1/16
EXAM PACKAGE 2026/2027 Exams | Actual Questions &
Verified Answers | Comprehensive Genetics Assessment |
Pass Guarantee
BIOD210 Exam 1: Mendelian Foundations
1. In a monohybrid cross between two heterozygous tall pea plants (Tt × Tt), what is
the expected phenotypic ratio in the F₁ generation?
A. 1:2:1
B. 3:1
C. 1:1
D. 2:1
Correct Answer: B
Rationale: 3 tall : 1 short. Genotypic ratio is 1 TT : 2 Tt : 1 tt, but phenotype shows
complete dominance.
2. A test-cross is performed to determine the genotype of a tall pea plant. If the
unknown plant is homozygous (TT), what will be the phenotypic ratio of its
offspring when crossed with a homozygous recessive (tt)?
A. All tall
B. 1 tall : 1 short
C. 3 tall : 1 short
D. All short
Correct Answer: A
Rationale: TT × tt → all Tt (tall). A 1:1 ratio would indicate the unknown was
heterozygous.
, 3. In humans, brown eyes (B) are dominant over blue (b). A brown-eyed man and a
blue-eyed woman produce a blue-eyed child. What is the man’s genotype?
A. BB
B. Bb
C. bb
D. Cannot be determined
Correct Answer: B
Rationale: Child is bb → must receive b from each parent. Man must be Bb (carrier).
4. Which of the following best describes Mendel’s Law of Independent Assortment?
A. Alleles separate during gamete formation
B. Genes on the same chromosome assort together
C. Genes for different traits segregate independently if on different
chromosomes
D. Dominant alleles always mask recessive ones
Correct Answer: C
Rationale: Independent assortment applies to genes on different chromosomes (or far
apart on the same chromosome).
5. In a dihybrid cross (AaBb × AaBb), how many different gamete genotypes can
each parent produce?
A. 2
B. 4
C. 6
D. 8
Correct Answer: B
Rationale: 2ⁿ where n = number of heterozygous gene pairs; here n = 2 → 4 gamete
types (AB, Ab, aB, ab).
6. What is the probability of obtaining an AaBb individual from a cross between
AaBb and AABB?
A. 1/16
