What is the primary distinction between autosomes and sex chromosomes?

The primary distinction between autosomes and sex chromosomes lies in the role that sex chromosomes play in determining an organism's sex. Sex chromosomes, which in humans are designated as X and Y, are specifically involved in sex determination and carry genes that influence sexual characteristics. In humans, typically females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

On the other hand, autosomes are the chromosomes that are not involved in determining sex; they are the remaining pairs of chromosomes that carry the majority of genetic information necessary for the organism's development, function, and traits. Humans have 22 pairs of autosomes and these chromosomes are present in both males and females, contributing equally to the individual's traits regardless of sex.

Both autosomes and sex chromosomes are inherited from parents to offspring, but the key differentiator is that sex chromosomes specifically dictate the biological sex of the organism, while autosomes are not linked to this function. The distinction is foundational in genetics, particularly in understanding inheritance patterns and sex-linked traits.