Advanced Placement (AP) Biology Practice Exam

What does Mendel's Law of Segregation state?

1. Alleles segregate from one another during gamete formation

2. Non-linked genes assort independently in metaphase

3. All alleles are expressed equally in the phenotype

4. Only one allele is passed on during reproduction

The correct answer is: Alleles segregate from one another during gamete formation

Mendel's Law of Segregation states that during the formation of gametes, the two alleles for a trait separate from each other so that each gamete carries only one allele for each gene. This principle is fundamental in understanding how traits are inherited from parents to offspring, as it explains how the genetic variability arises in the offspring. When gametes are formed through the process of meiosis, each parent contributes one allele to their offspring, ensuring that the genetic information is randomly and independently distributed. This law highlights the idea that alleles for each gene are separated during gamete production and that the combination of these alleles in the offspring determines the inherited traits. The other options relate to different aspects of Mendelian genetics. While non-linked genes assort independently pertains to the Law of Independent Assortment, the assertion about all alleles being expressed equally addresses the concept of incomplete dominance or codominance but does not pertain to Mendel's segregation principle. Additionally, the idea that only one allele is passed on during reproduction is a simplification of the process and does not capture the complete mechanism described by the law.