BIOL 210 Module 2: Genetics Examination Updated and Latest Questions and Correct Answers with Rationale

BIOL 210 Module 2: Genetics Examination Updated
and Latest Questions and Correct Answers with
Rationale
1. Which of the following describes the fundamental law of segregation?
A. Alleles for different traits sort independently during gamete formation.

B. The phenotype of an organism is always a blend of the parental traits.

C. Offspring always inherit the dominant phenotype if one parent is homozygous dominant.
D. Each individual possesses two alleles for a trait, and these alleles separate during
gamete formation.
Correct Answer: D
Explanation: The Law of Segregation states that the two alleles for a heritable character
separate (segregate) during gamete formation and end up in different gametes.

2. What is the expected phenotypic ratio of a monohybrid cross between two individuals that
are heterozygous (Aa x Aa)?
A. 1:2:1

B. 9:3:3:1

C. 1:1

D. 3:1

Correct Answer: D
Explanation: In a monohybrid cross between two heterozygotes, the typical phenotypic
ratio is 3 (dominant phenotype) to 1 (recessive phenotype).

3. In a Punnett square, the letters on the outside of the square represent:
A. The possible gametes produced by the parents.

B. The possible genotypes of the offspring.

C. The physical appearance of the parents.

D. The total number of alleles in the population.

Correct Answer: A
Explanation: The outside of a Punnett square represents the alleles contained in the
gametes of each parent.

,4. An organism with two identical alleles for a specific gene is said to be:
A. Heterozygous

B. Homozygous

C. Hemizygous

D. Dihybrid
Correct Answer: B
Explanation: Homozygous refers to having two identical alleles (e.g., AA or aa) for a
particular gene.

5. If a plant with purple flowers (PP) is crossed with a plant with white flowers (pp), what will
the genotype of the F1 generation be?
A. PP

B. pp

C. 1/2 Pp and 1/2 pp

D. Pp

Correct Answer: D
Explanation: A cross between homozygous dominant (PP) and homozygous recessive (pp)
results in 100% heterozygous (Pp) offspring.

6. Which law states that the inheritance of one trait has no effect on the inheritance of
another?
A. Law of Dominance

B. Law of Segregation

C. Law of Linkage

D. Law of Independent Assortment
Correct Answer: D
Explanation: The Law of Independent Assortment states that genes for different traits can
segregate independently during the formation of gametes.

7. What is the genotypic ratio of the F2 generation in a standard Mendelian monohybrid cross
(Aa x Aa)?
A. 3:1

B. 1:1

C. 4:0

, D. 1:2:1

Correct Answer: D
Explanation: The genotypic ratio is 1 AA : 2 Aa : 1 aa.

8. A ‘test cross’ is performed by crossing an individual with a dominant phenotype but
unknown genotype with an individual that is:
A. Homozygous dominant

B. Heterozygous

C. Homozygous recessive

D. Phenotypically identical

Correct Answer: C
Explanation: A test cross involves breeding the mystery individual with a homozygous
recessive individual to reveal the unknown genotype.

9. Which of the following represents a dihybrid cross?
A. AaBb x AaBb

B. AA x aa

C. Aa x Aa

D. AABB x aabb
Correct Answer: A
Explanation: A dihybrid cross involves individuals that are heterozygous for two different
traits.
10. If ‘T’ represents tall plants and ‘t’ represents short plants, what is the phenotype of a
plant with the genotype ‘Tt’?
A. Short

B. Medium height

C. Tall

D. Intermediate

Correct Answer: C
Explanation: In complete dominance, the presence of one dominant allele (T) results in the
dominant phenotype (Tall).

11. Mendel’s ‘factors’ that are passed from parents to offspring are now known as:
A. Chromatids