Humber Admissions Practice Test

What do we use to represent different forms of a gene?

1. Phenotypes

2. Genotypes

3. Alleles

4. Chromosomes

The correct answer is: Alleles

The correct answer is alleles, which are different forms of a gene that can arise through mutations or variations in the genetic material. Alleles occupy the same location on homologous chromosomes and can vary in their sequence, leading to different traits being expressed in the organism. For example, a gene for flower color in plants may have multiple alleles; one might code for red flowers, while another codes for white flowers. Phenotypes refer to the observable traits or characteristics of an organism, which result from the interaction of the genotype (the genetic makeup including the alleles) with the environment. Thus, while phenotypes are related to alleles, they do not specifically represent different forms of a gene. Genotypes describe the specific genetic constitution of an organism, particularly in terms of its alleles. For instance, if an organism has two different alleles for a gene (one from each parent), it would be considered heterozygous, but the term genotype encompasses the specific combination rather than just the alleles themselves. Chromosomes are the structures that organize and carry genetic information, including multiple genes and their alleles. However, chromosomes do not represent the different forms of a gene but rather serve as carriers of genetic material. Thus, alleles