Living Environment Regents Practice Test

How does the genetic makeup of skin cells differ from that of gametes?

1. Skin cells contain all chromosomes, gametes contain half

2. Skin cells are mutation-prone, gametes are not

3. Skin cells can easily reprogram, gametes cannot

4. Skin cells are uniform, gametes are diverse

The correct answer is: Skin cells contain all chromosomes, gametes contain half

The correct answer highlights a fundamental concept in genetics regarding the number of chromosomes contained within different types of cells. Skin cells, which are somatic cells, contain the full set of chromosomes found in an organism, which is characteristic of diploid cells. In humans, this means they possess 46 chromosomes, organized into 23 pairs. In contrast, gametes—specialized reproductive cells such as sperm and eggs—are haploid, which means they contain only half the number of chromosomes. In humans, this amounts to 23 individual chromosomes. This reduction in chromosome number during gamete formation is essential for sexual reproduction; when two gametes combine during fertilization, they restore the diploid number in the resulting zygote. Understanding this difference in chromosome number is crucial because it directly relates to processes like meiosis, where diploid cells undergo division to produce haploid gametes, allowing for genetic variation and integrity of chromosome numbers across generations. This foundational genetic principle underpins much of the study of inheritance and reproduction.