What is a chromosome and how many chromosomes are in a typical human somatic cell?

• A. A chromosome is a DNA molecule with proteins; humans have 46 chromosomes in somatic cells (23 pairs).
• B. A chromosome is a lipid droplet; humans have 24 chromosomes.
• C. A chromosome is a protein strand; humans have 30 chromosomes.
• D. A chromosome is a vesicle; humans have 52 chromosomes.

Answer: (A)

A chromosome is a DNA molecule wrapped around proteins, forming a compact structure that carries genetic information. In humans, somatic (body) cells are diploid and contain 46 chromosomes, arranged as 23 pairs. This includes 22 autosomes and one pair of sex chromosomes. Gametes (sperm and egg) have 23 chromosomes, so fertilization restores the 46-chromosome count in the zygote. The other descriptions (lipid droplet, protein strand, vesicle) do not describe what a chromosome is, and their suggested numbers don’t match the human somatic chromosome count.