Q- How do substances like CO2 and water move in and out of the cell? Discuss.
Answer- Substances like CO2 and water move in and out of the cell through different processes. The carbon dioxide always moves out of the cells into blood in tissue respiration because the partial pressure of carbon dioxide is higher in the cells (Pco2 = 52 mm Hg) than that of blood (Pco2 = 40 mm Hg). This occurs by the process of diffusion whereas water moves into the root hair from the soil solution on the principle of osmosis because the soil solution is less concentrated while cell sap of root hair is more concentrated.