Distinguish between the following paired terms: 
(b) heterozygous and homozygous, 

Verified step by step guidance

1. Step 1: Understand that both terms, heterozygous and homozygous, relate to the genetic makeup (genotype) of an organism at a specific gene locus.
2. Step 2: Define homozygous as having two identical alleles for a particular gene. This means both copies of the gene inherited from each parent are the same (e.g., AA or aa).
3. Step 3: Define heterozygous as having two different alleles for a particular gene. This means the two gene copies inherited from each parent differ (e.g., Aa).
4. Step 4: Recognize that these differences in alleles can affect the organism's traits (phenotype), depending on whether the alleles are dominant or recessive.
5. Step 5: Summarize by contrasting the two: homozygous means identical alleles at a gene locus, while heterozygous means different alleles at that locus.

Key Concepts

Homozygous

Homozygous refers to having two identical alleles for a specific gene on both homologous chromosomes. This means the organism inherits the same version of a gene from each parent, resulting in a uniform genetic expression for that trait.

Heterozygous

Heterozygous describes having two different alleles for a particular gene on homologous chromosomes. This genetic variation can lead to dominant-recessive interactions, where one allele may mask the expression of the other.

Alleles and Gene Expression

Alleles are different forms of a gene that determine specific traits. Understanding how alleles interact—whether identical or different—is essential to grasping the concepts of homozygosity and heterozygosity, as these interactions influence an organism's phenotype.