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Factors that effect membrane permeability
1) The nature of substance : size / polar non polar
2) presence of transport proteins : Channel + Carrier protein → allow water to pass through
3) temperature effect + Solvents + Cholesterol levels
Temperature ( increase )
Increase in temp = give more kinetic energy to the molecules to move around + faster
The phospholipid acquires more energy = move around more , which increases the membrane fluidity.
→ affect the unfolding of plasma membrane during phagocytosis.
Change the ability of cellls to signal to other cells by releasing chemical.
Temperature ( decreasing)
Decrease in temp = decrease in kinetic energy → causing the molecules to slow down
Saturated fatty acids —> compressed
However : Unsaturated fatty acids make up the cell membrane phospholipid bilayer as they become compressed, the kinks in their tails will push the adjacent phospholipid molecules away. = to maintain the membrane fluidity.
At cold temp : the proportion of unsaturated + saturated fatty acid will determine the membrane’s fluidity.
Cholesterol
Cholesterol acts as a buffers the effect of lowered temp, to prevent a reduction in the membrane’s fluidity
By preventing the phospholipid molecules from packing together too closely, cuz cholesterol molecules are in between groups of phospholipid molecules.
Effects of solvents on phospholipid
Eg : Acetone & Ethanol will damage cell membrane as they dissolve lipids.
