GRE Biology Mock Exam -Gene cs – Mendel, Linkage, Mapping
Sec on A: Mul ple Choice Ques ons (50)
Mendelian Principles (Q1–Q15)
1. In a Mendelian monohybrid cross, the F2 phenotypic ra o is:
A) 3:1
B) 1:2:1
C) 9:3:3:1
D) 2:1
2. Which of the following is an excep on to Mendel’s law of independent assortment?
A) Codominance
B) Linkage
C) Segrega on
D) Epistasis
3. In a dihybrid cross of two heterozygotes, the number of different gametes produced by each
parent is:
A) 2
B) 4
C) 8
D) 16
4. The law of segrega on occurs during:
A) Mitosis
B) Meiosis I
C) Meiosis II
D) Fer liza on
5. A test cross always involves crossing with a:
A) Homozygous dominant
B) Homozygous recessive
C) Heterozygous
D) Any of the above
6. If tall (T) is dominant over dwarf (t), a cross of Tt × Tt gives what genotypic ra o?
A) 1:2:1
B) 3:1
C) 2:1
D) 1:1
7. Which of the following describes incomplete dominance?
A) Both alleles expressed fully
B) One allele masks another
C) Blending of traits in heterozygotes
D) None
, 8. Codominance is best illustrated by:
A) Human skin color
B) ABO blood group system
C) Pea flower color
D) Height in humans
9. A cross of Aa × Aa gives what probability of producing aa offspring?
A) 1/2
B) 1/4
C) 3/4
D) 1/8
10. The dihybrid cross phenotypic ra o 9:3:3:1 can be explained by:
A) Gene linkage
B) Independent assortment
C) Segrega on only
D) Muta on
11. Which principle states that alleles separate into different gametes?
A) Law of dominance
B) Law of segrega on
C) Law of independent assortment
D) Law of purity
12. In Mendel’s pea experiments, yellow seed color was dominant to green. Crossing two
heterozygous yellow plants gives what propor on of green seeds?
A) 25%
B) 50%
C) 75%
D) 0%
13. If both parents are carriers of cys c fibrosis (autosomal recessive), the chance of an affected
child is:
A) 25%
B) 50%
C) 75%
D) 100%
14. Which of the following traits does not follow simple Mendelian inheritance?
A) Pea flower color
B) ABO blood groups
C) Sickle-cell trait
D) Tall/dwarf pea plants
15. Which of the following is an example of epistasis?
A) Albinism masking coat color
B) ABO codominance
C) Incomplete dominance in snapdragons
D) Hun ngton’s disease inheritance
Sec on A: Mul ple Choice Ques ons (50)
Mendelian Principles (Q1–Q15)
1. In a Mendelian monohybrid cross, the F2 phenotypic ra o is:
A) 3:1
B) 1:2:1
C) 9:3:3:1
D) 2:1
2. Which of the following is an excep on to Mendel’s law of independent assortment?
A) Codominance
B) Linkage
C) Segrega on
D) Epistasis
3. In a dihybrid cross of two heterozygotes, the number of different gametes produced by each
parent is:
A) 2
B) 4
C) 8
D) 16
4. The law of segrega on occurs during:
A) Mitosis
B) Meiosis I
C) Meiosis II
D) Fer liza on
5. A test cross always involves crossing with a:
A) Homozygous dominant
B) Homozygous recessive
C) Heterozygous
D) Any of the above
6. If tall (T) is dominant over dwarf (t), a cross of Tt × Tt gives what genotypic ra o?
A) 1:2:1
B) 3:1
C) 2:1
D) 1:1
7. Which of the following describes incomplete dominance?
A) Both alleles expressed fully
B) One allele masks another
C) Blending of traits in heterozygotes
D) None
, 8. Codominance is best illustrated by:
A) Human skin color
B) ABO blood group system
C) Pea flower color
D) Height in humans
9. A cross of Aa × Aa gives what probability of producing aa offspring?
A) 1/2
B) 1/4
C) 3/4
D) 1/8
10. The dihybrid cross phenotypic ra o 9:3:3:1 can be explained by:
A) Gene linkage
B) Independent assortment
C) Segrega on only
D) Muta on
11. Which principle states that alleles separate into different gametes?
A) Law of dominance
B) Law of segrega on
C) Law of independent assortment
D) Law of purity
12. In Mendel’s pea experiments, yellow seed color was dominant to green. Crossing two
heterozygous yellow plants gives what propor on of green seeds?
A) 25%
B) 50%
C) 75%
D) 0%
13. If both parents are carriers of cys c fibrosis (autosomal recessive), the chance of an affected
child is:
A) 25%
B) 50%
C) 75%
D) 100%
14. Which of the following traits does not follow simple Mendelian inheritance?
A) Pea flower color
B) ABO blood groups
C) Sickle-cell trait
D) Tall/dwarf pea plants
15. Which of the following is an example of epistasis?
A) Albinism masking coat color
B) ABO codominance
C) Incomplete dominance in snapdragons
D) Hun ngton’s disease inheritance
