IMG_20240406_0014.pdf - Biology: Water Movement Across Cell Membranes - PDF

While water molecules are free to pass across the plasma membrane in both directions, more water will enter the cell than leave. The net (over all) result is that water enters the celi. In such a situation, cell is likely to swe1l up, i.e., becortie inflated or turgid (Figure 18A). Such swollen RBCs...

While water molecules are free to pass across the plasma membrane in both directions, more water will enter the cell than leave. The net (over all) result is that water enters the celi. In such a situation, cell is likely to swe1l up, i.e., becortie inflated or turgid (Figure 18A). Such swollen RBCs may ultimately burst, 1.e,, A haemolysed. (Figure 198). 2. If the medium surrounding the cell is of exactly the same of no net movement ceil, there will be concentration as the water water across the plasma membrane (Figure 1BB and Figure 19A). Such a solution is called isotonic solution (e.g., Ringers solution is an isotonic solution for the animal cells). B Hypotonic solution case, water crosses the plasma membrane in both directions, but the amount going in is the same as the amount going out, so there is no overall movement of water. In such a situation, the cell rt ill maintain the same size. In this 3. If the medium has a lower concentration of water than the cell, i.e., if it is very concentrated solution, the cell wiil lose water bv osmosis. Such a concentrated solution is called hypertonic solution. In this case too, water crosses the piasma membrane in both directions, but this time more water ieaves the cell than enters it. Therefore, the cell will shrink. In this situation, plant cell is said to be plasmolysed (Figure 18C and Figure 26D) and animal ceils I c lsotonic solution (Red blood cells) is said to crenated (Figure 19C). Hypertonic solution ure tr 8, Effect of different solutions on plant cells..1 B Blooc + Ringers salulron :^ Y P-aia=- --\. 22 B l.-i...'j"_.:.:..-..- 1..' i Slidesho,,'. Elood + conc" sall Blood + water ^l -:'"', :: -, - ".:tl,:ii.:i.,.:llenandhaemolysedRBCs(B) andshrunkenorcrenatedRBCs(C). The Fundomentol Unit of Life: Cell J