Which term describes the set of alleles that an organism carries for a particular gene, regardless of whether they are expressed?

• A. Genotype
• B. Allele
• C. Phenotype
• D. Food web

Answer: (A)

The idea being tested is understanding what the genetic makeup for a gene means—the set of alleles an organism carries. In diploid organisms, you have two copies of each gene, one from each parent, and these two alleles together form the genotype. The genotype describes the actual alleles present, regardless of whether they are expressed as a trait. For a gene with alleles A and a, the possible genotypes are AA, Aa, or aa, reflecting the alleles inherited rather than what you see.

The observable trait, which can depend on dominance and environment, is the phenotype, not the complete set of alleles. An allele is a single variant of the gene, not the whole combination carried for that gene. A food web is unrelated to genetics.