Question

what number and types of chromosomes are found in a human somatic cell?
○ 21 autosomes and 2 sex chromosomes
○ 44 autosomes and 2 sex chromosomes
○ n chromosomes
○ 22 autosomes and 1 sex chromosome
○ 45 autosomes and 1 sex chromosome

Explanation:

Human somatic cells are diploid (2n). Humans have 23 pairs of chromosomes in total. Out of these, 22 pairs are autosomes (non - sex chromosomes) and 1 pair is sex chromosomes (XX for females, XY for males). So the total number of autosomes is \(22\times2 = 44\) and the number of sex chromosomes is 2 (either XX or XY). Let's analyze each option:

• Option "21 autosomes and 2 sex chromosomes": Incorrect, as there are 22 pairs of autosomes.
• Option "44 autosomes and 2 sex chromosomes": Correct, as 22 pairs of autosomes give 44 autosomes and 1 pair of sex chromosomes gives 2 sex chromosomes.
• Option "\(n\) chromosomes": Incorrect, somatic cells are diploid (\(2n\)), and \(n\) is the haploid number (for gametes).
• Option "22 autosomes and 1 sex chromosome": Incorrect, this would be the number in a haploid cell (gamete) for autosomes and sex chromosome count is also wrong for somatic cells.
• Option "45 autosomes and 1 sex chromosome": Incorrect, the number of autosomes is 44 and sex chromosomes is 2.

Answer:

B. 44 autosomes and 2 sex chromosomes