Cells need to grow primarily so that organisms can grow, develop, and maintain their tissues, while also optimizing efficiency.
Why Cellular Growth is Essential
Here's a more detailed breakdown:
-
Organismal Growth: The most straightforward reason cells grow is to enable the growth of the organism as a whole. In multicellular organisms, more cells are needed for the organism to increase in size. As stated in the reference material, in order for organisms to grow, body cells either have to increase their size or divide.
-
Tissue Repair and Maintenance: Cells are constantly being damaged or dying. To maintain the integrity of tissues and organs, new cells must be generated through growth and division to replace the old or damaged ones.
-
Development: During embryonic development and later stages of growth, cells grow and differentiate to form specialized tissues and organs. This process is tightly regulated to ensure proper form and function.
-
Optimizing Surface Area to Volume Ratio: As a cell grows, its volume increases faster than its surface area. This becomes a problem because the cell relies on its surface area (the cell membrane) to take in nutrients and expel waste. If the cell becomes too large, the surface area becomes insufficient to support the volume, impairing efficiency and ultimately requiring cell division to restore a more favorable ratio. Smaller cells are generally more efficient.
-
Avoiding DNA Overload: Similar to the surface area to volume ratio, the cell's DNA can only manage a certain volume effectively. As the cell grows, the demand on the DNA increases. If the cell becomes too large, the DNA can't provide enough instructions for the cell's functions, necessitating cell division to create new cells with their own DNA.
In summary, cellular growth is essential for the survival and proper functioning of all living organisms, playing a crucial role in development, repair, and overall maintenance.
