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Factors affecting the permeability of the Cell Membrane Temperature and ethanol You should be able to: Outline the effects of changing temperature on membrane structure and permeability Effect of temperature on Beetroot Betalain is the pigment that gives beetroot its dark red colour. Q:Where is the pigment is found in the living beetroot cells? vacuole Q:What structures does the pigment pass through to get out of the cells? Tonoplast and cell surface membrane Effect of temperature on Beetroot If you soak pieces of beetroot in water of different temperatures the following results are obtained. 20oC Room 45oC 50oC 55oC 60oC 65oC ethanol Effect of temperature on Beetroot Q:Why is the pigment likely to leak out at higher temperatures? Increasing temperatures gives molecules more KINETIC ENERGY Phospholipids move more quickly at high temperatures, making the membrane more fluid, leading to its breakdown and the leakage of the pigment Proteins (channel and carrier) are denatured by the heat so no longer effectively control what enters and leaves through the membrane. Effect of temperature on Beetroot What happens if you use ethanol? Does this cause the pigments to leak out at lower temperatures than water? Does ethanol have any chemical properties that are different from water that might affect the "waterproofing" of the cell membrane? Ethanol can dissolve phospholipids, and so can act like a detergent - punching holes in membranes.