Advanced Placement (AP) Biology Practice Exam

What does the term allele refer to?

1. Different forms of a gene

2. A specific protein coded by DNA

3. A visual representation of traits

4. The physical manifestation of traits

The correct answer is: Different forms of a gene

The term allele refers to different forms of a gene. Genes, which are segments of DNA, can exist in multiple variations, and these variations are what we refer to as alleles. For example, a gene that determines flower color in a plant might have an allele for red flowers and an allele for white flowers. Each individual inherits one allele from each parent, and the combination of these alleles determines the organism's genetic makeup for that particular trait. This concept is fundamental in genetics, as it helps explain variations within a population and the inheritance of traits across generations. The other options relate to genetic concepts but do not accurately define what an allele is. A specific protein coded by DNA pertains to the process of gene expression, while a visual representation of traits would refer to a phenogram or family tree diagram, and the physical manifestation of traits describes phenotype, which is the result of alleles expressed but does not define the term allele itself.