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How does water move in and out of cells?

Last updated date: 14th Jul 2024
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Hint: Most molecules, but not all, are blocked by cell membranes. The creation of a cell membrane capable of allowing some materials to pass while restricting the movement of other molecules was a significant step in the evolution of the cell. Cell membranes are permeable barriers that separate the inner cellular environment from the outer cellular (or external) environment.

Complete answer:
Plant cells have a rigid cell wall in addition to the plasma membrane. Only certain particles can pass through the plasma membrane because it is selectively permeable. Because the membrane is made of lipids, charged or polar particles cannot pass through the uncharged lipid barrier without the assistance of carriers. Neutral particles with no charge will easily pass.

There are two modes of transportation:
• Active transport: Active transport uses energy in the form of ATP to move molecules and ions from low concentration to high concentration. Active transport necessitates the use of energy, such as a sodium channel.

• Passive transport: Without using any energy, passive transport moves molecules and ions from a higher concentration to a lower concentration. Osmosis and diffusion are examples of passive transport because they do not require energy.

Osmosis allows water to pass through the membrane. The process is carried out by aquaporins (channels) in the cell membrane. Water, like diffusion, follows the concentration gradient. If the concentration outside the cell exceeds the inside, water will flow. Osmosis exhibits selective permeability of the membrane.

Note: Simple diffusion and osmosis are similar in that the solute particles move in simple diffusion. The solvent (usually water) moves across a membrane to dilute the solute particles in osmosis.