Re: What effect do alkalis have on the cell membrane?

Hi Rosie,

There are a lot of things that happen with a cell when placed in an
alkaline environment. If we are talking about a really strong base, then we
expect to see a denaturing (unwinding, braking) of the proteins in and
around the membranes and also a disruption of the fat layers of the
membranes. As you might know the fatty acids in a cell membrane are mostly
in the form of so-called diacyl glycerols (DAG): these guys have two fatty
tails pointing into the membrane and a more water soluble “head” pointing
out. An effect of a strong base would be to detach the fatty tails from the
head. The membrane would brake up and the process would go even faster due
to the fact that the now free fatty acids will act like detergents and
pretty well dissolve the membrane. If you happen to get some alkali on your
fingers, you will notice that they get slippery, just like soap. Don’t try
this on purpose though, as the next step is a really itchy, ugly and
long-lasting sore.

Now, if we would be less drastic and add a weaker base to the outside of a
cell, we would disturb the proteins transferring molecules across it. One
way some of these so-called transporters work is to use an electric charge
across the membrane to drive the transfer. The outside of the membrane is
positively charged and the inside negative. By adding a base, you add
negative charges to the outer side which destroys this effect. From this it
follows that the cell will then work like mad to try to compensate and thus
deplete itself of all its chemical energy. And die. Of starvation.

I hope this answers your question!
Kind regards,
Erik