biol 107 (2)

Phospholipid membranes exposed to heat 

become too fluid

Proteins embedded in membranes exposed to heat

can denature

Phospholipid membranes exposed to cold

can solidify

If the cell's internal water gets too cold

the water can expand and rupture the cell or an ice crystal can form

Detergents can cause membranes to 

buckle or break

what are the functions of membranes?

separation of the cell contents from external enviroment, organization of chemicals , reactions into specific organelles, and transport of certain molecules in/ out if the cell

what is the structure of a cell membrane?

phospholipid bilayer with embedded proteins and sometimes other molecules

how does cholesterol affect membrane stability

cholesterol helps increase membrane stability

how can detergents disrupt membranes

detergents are amphipathic molecules; like phospholipids they have both hydrophobic and hydrophobic portions. the difference is their overall shape: phospholipids have a cylindrical shape and detergents can be con shaped. by ‘wedging’ cones into a double plane of cylinders, you can cause the plane to buckle or break