cell population proliferation

Definition

Target type: biologicalprocess

The multiplication or reproduction of cells, resulting in the expansion of a cell population. [GOC:mah, GOC:mb]

Cell population proliferation is a fundamental biological process that drives the growth and development of organisms. It involves a series of tightly regulated events that ensure the accurate duplication of cellular components and the creation of new, functional cells. This process is essential for maintaining tissue homeostasis, replacing damaged cells, and promoting organismal growth.

The proliferation process can be broadly divided into two main phases:

**1. Interphase:** This is the longest phase of the cell cycle and is characterized by significant cellular growth, DNA replication, and preparation for cell division. It is further subdivided into three stages:

**a. G1 Phase (Gap 1):** The cell grows in size, synthesizes proteins, and accumulates energy. This is a period of intense metabolic activity, with the cell preparing for DNA replication. During this phase, the cell assesses its environment and internal state to determine if conditions are suitable for cell division. If conditions are favorable, the cell will progress through the G1 checkpoint, a critical point of no return, committing it to the cell cycle.

**b. S Phase (Synthesis):** This is the stage where DNA replication occurs. Each chromosome is duplicated, ensuring that each daughter cell will receive a complete set of genetic material. This process is highly regulated, with multiple checkpoints to ensure accuracy and prevent errors.

**c. G2 Phase (Gap 2):** The cell continues to grow and produce proteins, particularly those involved in cell division. It also undergoes a final checkpoint to ensure that DNA replication is complete and the cell is ready to enter mitosis.

**2. M Phase (Mitosis):** This is the stage where the cell divides into two daughter cells. It consists of four distinct phases:

**a. Prophase:** The replicated chromosomes condense, becoming visible under a microscope. The nuclear envelope breaks down, and the spindle fibers, composed of microtubules, begin to form.

**b. Metaphase:** The chromosomes line up along the equator of the cell, attached to the spindle fibers at their centromeres. This arrangement ensures that each daughter cell receives an equal number of chromosomes.

**c. Anaphase:** The sister chromatids, which are the two identical copies of each chromosome, separate and move towards opposite poles of the cell, pulled by the spindle fibers.

**d. Telophase:** The chromosomes reach the poles of the cell and begin to decondense. New nuclear envelopes form around each set of chromosomes, and the cytoplasm divides, forming two distinct daughter cells. This process, called cytokinesis, involves the formation of a cleavage furrow in animal cells or a cell plate in plant cells.

The entire process of cell proliferation is tightly regulated by a complex network of signaling pathways, including growth factors, cyclins, and cyclin-dependent kinases (CDKs). These signaling molecules ensure that cells divide only when necessary and that the process occurs accurately. Disruption of these pathways can lead to uncontrolled cell proliferation, a hallmark of cancer.

Furthermore, the proliferation process is influenced by external factors such as nutrients, oxygen availability, and contact with other cells. This interplay between internal and external signals ensures that cell proliferation occurs in a controlled and coordinated manner, contributing to the overall health and development of the organism.'
"

Proteins (40)

Compounds (1,336)