The egg cells of a horse contain 32 chromosomes. How many chromosomes are in the horse’s liver cells?
64
128
16
none
32
The correct answer and explanation is:
The correct answer is 64.
Explanation:
In most animals, including horses, the egg cells (or any gametes) contain half the number of chromosomes found in the somatic cells, which are the cells that make up the body tissues like liver, muscles, and skin. This reduction in chromosome number occurs through a type of cell division known as meiosis.
In this case, the egg cell of a horse has 32 chromosomes. This is because it is a gamete (reproductive cell) and only contains half of the horse’s full chromosome set. The liver cells, on the other hand, are somatic cells and contain the full set of chromosomes. Since the chromosome number in somatic cells is double that in the gametes, the horse’s liver cells will contain 64 chromosomes.
The process that restores the full chromosome number occurs when an egg cell (with 32 chromosomes) fertilizes a sperm cell (also with 32 chromosomes). The resulting zygote will have 64 chromosomes, with 32 coming from the egg and 32 coming from the sperm. As the zygote divides and grows into a horse, its somatic cells, including liver cells, will each contain the full set of chromosomes (64).
This consistent doubling in chromosome number ensures that each generation maintains the same genetic stability, which is crucial for the proper functioning of an organism.