What is osmosis?

Osmosis is defined as the movement of water across a semipermeable membrane from a region of low solute concentration to a region of high solute concentration. This process is vital for maintaining the balance of fluids in biological systems, as it helps regulate the internal environment of cells. In an aqueous solution, when solute concentration varies, water will naturally move towards the area where there is a higher concentration of solute to equalize the solute concentrations on both sides of the membrane.

This characteristic of osmosis is crucial for various biological functions, such as nutrient absorption in root cells of plants and the regulation of cellular hydration. Understanding osmosis is fundamental in fields such as biology and chemistry, as it illustrates how substances move across membranes, which is essential for life processes.

In contrast, the other options refer to different biological processes. The transport of proteins across cell membranes relates to facilitated diffusion or active transport, the movement of nutrients within plants pertains to translocation through vascular tissues (xylem and phloem), and gas exchange during photosynthesis describes the uptake of carbon dioxide and release of oxygen, which is unrelated to the movement of water across membranes.