In haploid notation, what does n represent?

In haploid notation, what does n represent?

• A. The number of chromosomes in a somatic cell
• B. The number of chromosomes in a gamete
• C. The total number of genes
• D. The number of chromosome pairs

Answer: (B)

In haploid notation, n is the number of chromosomes in a gamete—the haploid chromosome set. This means gametes carry a single set of chromosomes, so in humans n = 23. Somatic cells are diploid (2n), containing two sets of chromosomes (46 in humans), so 2n, not n, describes them. The total number of genes isn’t given by n, and n refers to individual chromosomes in a haploid set rather than chromosome pairs (in humans, there are 23 pairs in a diploid cell, but the haploid number is 23).

In haploid notation, n is the number of chromosomes in a gamete—the haploid chromosome set. This means gametes carry a single set of chromosomes, so in humans n = 23. Somatic cells are diploid (2n), containing two sets of chromosomes (46 in humans), so 2n, not n, describes them. The total number of genes isn’t given by n, and n refers to individual chromosomes in a haploid set rather than chromosome pairs (in humans, there are 23 pairs in a diploid cell, but the haploid number is 23).