Question #c4023
1 Answer
In order to sustain basic processes required to support life.
Explanation:
Sugar & other food molecules, amino acids, nucleotides - all rare in the environment but necessary for normal cell activities. Cells will spend energy to move molecules in the environment against a concentration gradient into their bodies and maintain this imbalance (wrt environment) because it gives them increased likelihood of survival.
In response to this imbalance, often water will diffuse into the cell via osmosis in order to achieve equilibrium - if this is not dealt with the cell will quickly lyse as the swelling bursts the cell membrane.
Paramecium (for example) have adapted to this with their contractile vacuole which actively pumps water out of the cell (via bulk transport) to sustain itself in the face of heavy osmotic pressure.
