Factors affecting membrane permeability

how do solvents affect membrane permeability

• some solvents such as ethanol dissolve the lipids in the cell membrane and so the cell membrane loses it structure

• some solvents increase membrane permeability more than others

• increasing the conc of solvent will also increase membrane permeability

• any solvent less polar than water or non polar will disrupt the membrane

how do temperatures below 0’C affect membrane permeability

• the phospholipids dont have much kinetic energy so they can’t move very much, so they’re packed closely together and the cell membrane is rigid.

• channel proteins and carrier proteins in the membrane denature ( losing their structure and function) increasing the permeability of the membrane

• ice crystals may form and pierce the membrane making it highly permeable when it thaws

how do temperatures between 0 and 45 degrees affect membrane permeability

• the phospholipids can move around and aren’t packed as tightly together, the membrane is partially permeable

• as the temp increases the phospholipids move more because they have more kinetic energy and this increases the permeability of the membrane

how do temperatures above 45 degrees affect membrane permeability

• the phospholipid bilayer starts to melt and the membrane becomes more permeable

• water inside the cell expands putting pressure on the membrane

• channel proteins and carrier proteins in the membrane denature so they can’t control what enters or leaves the cell increasing the permeability of the membrane