Somatic Cell Division: An Overview

Somatic Cell Division: An Overview

The classification of 'somatic cells' comprises all of the cells within the human body, with the exception of reproductive cells. The cell division cycle consists of two distinct periods: The first, known as interphase is when the cell is not dividing and is simply performing its essential life functions, including synthesizing the DNA that plays such a crucial role in the active reproductive phase. During the mitotic, or dividing phase, the cell nucleus divides and eventually creates two new daughter cells (Cell division, 2010, Ivy Rose UK).

Mitosis evolves over the course of several distinct phases. During prophase, the chromatin in the cell nucleus begins to condense and the nucleolus disappears. "Centrioles begin moving to opposite ends of the cell and fibers extend from the centromeres. Some fibers cross the cell to form the mitotic spindle" (Cell cycle, 1997, Bio project). When the cell enters protometophase, the nuclear membrane of the cell dissolves and "proteins attach to the centromeres creating the kinetochores. Microtubules attach at the kinetochores and the chromosomes begin moving," as the cell enters metaphase, when "spindle fibers align the chromosomes along the middle of the cell nucleus" (Cell cycle, 1997, Bio project).

During anaphase, the paired chromosomes within the cell separate at the kinetochores and move to opposite sides of the cell. "Motion results from a combination of kinetochore movement along the spindle microtubules and through the physical interaction of polar microtubules," and this stage followed by telophase, where new membranes form around the two newly developed nuclei (Cell cycle, 1997, Bio project). The chromosomes and spindle fibers are no longer visible and cytokinesis begins. During cytokinesis two new cells are finally formed as "a fiber ring composed of a protein called actin around the center of the cell contracts, pinching the cell into two daughter cells, each with one nucleus. In plant cells, the rigid wall requires that a cell plate be synthesized between the two daughter cells" (Cell cycle, 1997, Bio project).

Comparing and contrasting the male and female human skeletons

Although it is said we are 'all the same under the skin,' there are often appreciable differences in male and female skeletons. On average, male skeletons are larger than female skeletons, but just as some women are larger than some males, this distinction does not hold firm in all instances. Female pelvic regions tend to be wider than male pelvic regions, an evolutionary feature that has made childbirth easier. Female bones tend to be thinner and less dense than male bones, and thus the female skeleton tends to be lighter than male skeletons.