Ch. 10: Cell Growth and Division

10.1 Cell Growth, Division, and Reproduction

The larger a cell becomes, the more demands the cell places on its DNA. In addition, a larger cell is less efficient in moving nutrients and waste materials across the cell membrane. Asexual reproduction is the production of genetically identical offspring from a single parent. Offspring produced by sexual reproduction inherit some of their genetic information from each parent.

10.2 The Process of Cell Division

Chromosomes make it possible to separate DNA precisely during cell division. During the cell cycle, a cell grows, prepares for division, and divides to form two daughter cells. During prophase, the genetic material inside the nucleus condenses. During metaphase, the chromosomes line up across the center of the cell. During anaphase, the chromosomes separate and move along spindle fibers to opposite ends of the cell. During telophase, the chromosomes, which were distinct and condensed, begin to spread out into a tangle of chromatin. Cytokinesis completes the process of cell division—it splits one cell into two.

10.3 Regulating the Cell Cycle

The cell cycle is controlled by regulatory proteins both inside and outside the cell. Cancer cells do not respond to the signals that regulate the growth of most cells. As a result, the cells divide uncontrollably.

10.4 Cell Differentiation

During the development of an organism, cells differentiate into many types of cells.

The unspecialized cells from which differentiated cells develop are known as stem cells. Stem cells offer the potential benefit of using undifferentiated cells to repair or replace badly damaged cells and tissues. Human embryonic stem cell research is controversial because the arguments for it and against it both involve ethical issues of life and death.