Biol Formal Report 1

2526 WordsFeb 11, 201511 Pages
Carleton University BIOL 1003 Formal Lab Report: Lab #2 Cell Membranes: Diffusion and Osmosis Name: Shibani Choudhry Student Number: 100990428 Lab Partner: Tryston Charlton Lab section: Thursday AM Introduction Cells are comprised of a semi-permeable membrane surrounding a liquid cytoplasm wherein all process and organelles necessary for the cell’s survival are housed. For a cell to remain healthy, the movement of substances in and out of the cell is important. This can be achieved through a variety of processes but the simplest are osmosis and diffusion. Osmosis is the movement of free water molecules down a concentration gradient. Essentially, free water molecules will move to the side of the membrane where more solute is dissolved and less free water molecules are present. The movement of water depends on the difference between the internal and external environments of the cell. When cells are in an external environment concentration that is less than the internal, a hypotonic solution, free water molecules will move into the cell through osmosis and the cell will expand. Animal cells left in a hypotonic solutions for an extended period of time will burst because the cell membrane is not strong enough to contain the large amount of incoming water (Reece et. al. 2014). Conversely, plant cells will not lyse due to the strong cell wall that contains the cytoplasm. Plant cells will experience a high turgor pressure due to the expansion of the central, water-storing vacuole in the cytoplasm; this allows the leaf to remain upright when in a hypotonic solution. The ideal environment for animal cells is an isotonic solution where the concentration of their internal environment is similar to their external environment; this allows them to remain in a balanced state (Hoffman et. al. 2009). However, plant

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