Question
Why do animal cells burst when placed in pure water?
Answer
Animal cells burst when placed in pure water due to osmotic pressure differences. This phenomenon occurs because animal cells lack rigid cell walls, making them susceptible to changes in their surrounding environment.
Osmotic Pressure and Cell Bursting
Osmosis and Water Influx: When animal cells are placed in pure water, the water concentration outside the cell is higher than inside. Water moves into the cell through osmosis, leading to swelling and eventual bursting due to the lack of a protective cell wall (Beadle, 1934; Boulton-Stone and Blake, 1993; Tran and Hwang, 2014).
Absence of Cell Wall: Unlike plant cells, animal cells do not have a cell wall to provide structural support and resist osmotic pressure. This absence makes them more vulnerable to bursting when exposed to hypotonic solutions like pure water (Boulton-Stone and Blake, 1993; Tran and Hwang, 2014).
Mechanisms and Effects
Cell Membrane Permeability: The cell membrane’s permeability allows water to enter the cell rapidly, increasing internal pressure until the membrane can no longer contain it, resulting in cell lysis (Beadle, 1934; Boulton-Stone and Blake, 1993).
Stress and Damage: In bioreactor systems, the presence of bubbles can also cause mechanical stress on animal cells, contributing to cell damage and bursting. The stress from bubble bursting can exceed the cell’s tolerance, leading to cell death (Boulton-Stone and Blake, 1993; Tran and Hwang, 2014).
Conclusion
Animal cells burst in pure water primarily due to osmotic pressure differences, as water influx causes the cells to swell and eventually rupture. The lack of a cell wall in animal cells makes them particularly susceptible to this osmotic imbalance, leading to cell lysis. Additionally, mechanical stresses, such as those from bubble bursting, can exacerbate cell damage in certain environments.
References
Beadle, L., 1934. Osmotic Regulation in Gunda ulvae. The Journal of Experimental Biology, 11, pp. 382-396.
Boulton-Stone, J., & Blake, J., 1993. Gas bubbles bursting at a free surface. Journal of Fluid Mechanics, 254, pp. 437 – 466. https://doi.org/10.1017/S0022112093002216
Tran, T., & Hwang, W., 2014. Bubble bursting in bioreactor for animal cell culture. **, pp. 229-233.
