National League for Nursing (NLN PAX) Practice Exam

In genetics, what does the term phenotype refer to?

1. Genetic makeup

2. Physical appearance

3. Dominance pattern

4. Chromosomal structure

The correct answer is: Physical appearance

The term phenotype refers specifically to the observable physical characteristics or traits of an organism, which result from the interaction of its genetic makeup (genotype) and the environment. This can include traits such as height, color, shape, and behavior. The phenotype is essentially what you see, as opposed to the underlying genetic information that dictates those traits. In contrast, genetic makeup relates to the specific alleles or combinations of alleles that an organism possesses. Dominance patterns involve the relationships between different alleles at a gene locus and how they express themselves in the phenotype. Chromosomal structure refers to the organization and number of chromosomes within a cell but does not directly describe the observable traits of an organism. Thus, the correct understanding of phenotype is encapsulated in its definition as the physical appearance or observable traits resulting from genetic and environmental influences.