Biology Eei Essay examples

3504 WordsJan 18, 201315 Pages
| 2012 | | Toby Rheinberger Lab Partner: Jeremy Saba | [The Effect of surface area to volume ratio and solute concentration on osmosis.] | The aim of this experiment was to test the effect of surface area on osmosis and the effect of solute concentration on osmosis. To test this aim to hypotheses were devised. 1) If potato pieces are immersed in various salt solutions, then the pieces with the greatest surface area to volume ratio will experience the greatest weight change, because more water can move by osmosis across the potato cell’s semi permeable membrane. 2) If potato pieces are immersed in various salt solutions, then the pieces immersed in the most concentrated solution will experience he greatest weight change,…show more content…
A semi permeable membrane. (Biology at Aveson , 2007) Figure 2. A semi permeable membrane. (Biology at Aveson , 2007) pass through the membrane and into the cell. Despite its importance osmosis may also damage cells by causing them to; a) shrink from water loss or b) burst from too much water gain. Plant cells [fig 3] have adapted themselves to ensure that these factors do not affect them, by forming a ridged wall, known as the cell wall, around their cells. The cell wall maintains the shape of the cell, and prevents the cell from bursting in a hypotonic medium by resisting water pressure. Plant cells have also adapted a larger vacuole, which occupies 80% or more of the cells cytoplasm (Davidson, 2004); allowing plants to store more water and nutrients per cell. Vacuoles also play a structural role in plant cells; by swelling when liquids contact them, plant vacuoles are able to control turgor pressure within the cell. This helps maintain the structural integrity of the cell as well as providing the plant with suitable amounts of water and nutrients; however the cell will never burst because the vacuole is contained within the cell wall. If plant cells are deprived of water their vacuole will begin to shrink, yet due to the cell the wall, the plant cell will be able to maintain its shape. [fig.4] Animal cells [fig 5] on the other hand do not have this
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